# In Praise of the Centre Bit.



## Cheshirechappie (29 Oct 2014)

Some months ago, I 'invested' about £16 on a certain internet auction site, and in two seperate lots acquired a vintage 'sixpenny' brace and a selection of 32 brace bits. I've been doing a bit of cleaning and sharpening, and having a play about with them.

The bits consisted of several centre bits ranging from about 1/4" to 1", a handful of shell and nose bits, and a few countersinks (which I haven't really tested yet).

I can't say I'm all that impressed with the shell and nose bits. They cut a nice, clean hole, and work just as well if turned clockwise or anti-clockwise, but that hole's diameter may not relate to the bit size, nor might it be where you wanted the hole to start. My conclusion is that if you need smallish holes for (say) screw pilots or screw-shank clearance, a modern lip and spur bit, or even a jobber's twist drill, in an egg-beater hand drill will do a better job.

However, the centre bits were something of a revelation. For donkey's years, I've been using Jennings twist augers in the handbrace, and for holes up to about 3/4" they do a very fine job, but pushing one much bigger than that into hardwood is asking for a lot of grunt. Not so with the centre bits - a 1" centre bit will take out a nice, clean hole in beech without much strain in a 10" sweep brace. In softwood, it flies through. Even a 3/4" hole can be drilled through beech using the (7" sweep) sixpenny brace; with a Jennings auger, you need the 10" brace to turn it. One thing that helps with the centre bits is that you can control the rate of cut by how much you lean on the brace - the screw pitch of the twist auger pilots dictate their rate of feed, and all mine are a rather coarse pitch.

Hole quality is remarkably good. I think cleanliness of cut depends a bit on careful sharpening of the side spur, but all my centre bits cut pretty well dead on nominal size. I gather some can cut a bit oversize - maybe if the centre pilot is sharpened a bit off, they don't quite drill true.

Where a twist auger will score is in drilling deep holes. The centre bit can be made to go a little off-line if the brace is tilted a bit.

Another thing to note, in passing as it were, is how impressed I am with the sixpenny brace. It's such a simple little tool, but very effective. The bit holder is just a square tapered hole with a little thumbscrew to pinch the bit's taper and hold it, so changing bits is very quick indeed - much quicker than with the two-jaw screw chuck of the bigger brace. That said, it doesn't have the sweep or solidity of build to cope with bigger bits, but up to about 3/4" centre bits, I actually prefer it to the Stanley 10" ratchet brace.

So - if you have a brace, but haven't acquired any centre bits yet, go forth and grab a few. They can be picked up for very little on Ebay, and I'd imagine for virtually nothing at carboots. Sharpened up, a selection to hand in the workshop would be well worth while!


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## Eric The Viking (1 Nov 2014)

Got a few from grandfather-in-law. Will experiment. 

Thanks.


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## Cheshirechappie (1 Nov 2014)

Since the original post, I've found this blogpost by Shannon Rodgers (The Renaissance Woodworker) which has an embedded video mostly about centre bits, but with some reference to other brace bits. It's about 23 minutes long, so it's quite comrehensive and informative. He details the sharpening of centre bits from about 13 minutes in.

http://www.renaissancewoodworker.com/center-bits/

I found that if I sharpened with a file, it helped a bit to finish with a fine slipstone. (The other thing I've discovered is that sharpening the larger bits is easy, but doing the tiny ones is like watchmaking!)


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## marcros (9 Nov 2014)

On the strength of this thread, I have just treated myself to a set of 9 centre bits on eBay so that I can try them out. 1/4" up to 1 1/4" should cover most of what I will need!


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## Cheshirechappie (10 Nov 2014)

Marcros - would you be kind enough to post your impressions and experiences with them, once you've had a chance to give them a reasonable workout? It would be useful to know if my findings were reasonably typical or a lucky one-off!


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## marcros (10 Nov 2014)

yes, certainly.


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## bugbear (10 Nov 2014)

Cheshirechappie":1jwt1fp0 said:


> However, the centre bits were something of a revelation. For donkey's years, I've been using Jennings twist augers in the handbrace, and for holes up to about 3/4" they do a very fine job, but pushing one much bigger than that into hardwood is asking for a lot of grunt. Not so with the centre bits - a 1" centre bit will take out a nice, clean hole in beech without much strain in a 10" sweep brace. In softwood, it flies through. Even a 3/4" hole can be drilled through beech using the (7" sweep) sixpenny brace; with a Jennings auger, you need the 10" brace to turn it. One thing that helps with the centre bits is that you can control the rate of cut by how much you lean on the brace - the screw pitch of the twist auger pilots dictate their rate of feed, and all mine are a rather coarse pitch.
> 
> Hole quality is remarkably good. I think cleanliness of cut depends a bit on careful sharpening of the side spur, but all my centre bits cut pretty well dead on nominal size. I gather some can cut a bit oversize - maybe if the centre pilot is sharpened a bit off, they don't quite drill true.



The rate control is key - it also means you can take a fine "final cut" when drilling to excavate a cavity; it's very difficult to take "just a bit more" with a bit with a lead screw.

The other key point is the ease of access for proper sharpening, so (as you say) the side spur can be truly-polished-sharp (not just filed-sharp), leading to good hole quality. 

BugBear


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## Andy Kev. (10 Nov 2014)

bugbear":1i49qd76 said:


> Cheshirechappie":1i49qd76 said:
> 
> 
> > However, the centre bits were something of a revelation. For donkey's years, I've been using Jennings twist augers in the handbrace, and for holes up to about 3/4" they do a very fine job, but pushing one much bigger than that into hardwood is asking for a lot of grunt. Not so with the centre bits - a 1" centre bit will take out a nice, clean hole in beech without much strain in a 10" sweep brace. In softwood, it flies through. Even a 3/4" hole can be drilled through beech using the (7" sweep) sixpenny brace; with a Jennings auger, you need the 10" brace to turn it. One thing that helps with the centre bits is that you can control the rate of cut by how much you lean on the brace - the screw pitch of the twist auger pilots dictate their rate of feed, and all mine are a rather coarse pitch.
> ...



How do you go about achieving that level of sharpness? I noticed on the link to the Renaiscance Woodworker (provided above) that he justs uses a file. I guess that you have some specialist bit of sharpening kit in mind.


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## bugbear (10 Nov 2014)

Andy Kev.":392apzga said:


> How do you go about achieving that level of sharpness? I noticed on the link to the Renaiscance Woodworker (provided above) that he justs uses a file. I guess that you have some specialist bit of sharpening kit in mind.



Slip stones and/or SiC wrapped round dowels etc. Not (very) specialist, although not a 2x8 stone,I grant you.

BugBear


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## Andy Kev. (10 Nov 2014)

I suppose it's obvious, now that you say it! Particularly for the bigger sizes.


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## bugbear (10 Nov 2014)

Andy Kev.":2zj402so said:


> I suppose it's obvious, now that you say it! Particularly for the bigger sizes.



I find centre bits at their best around 3/8" - 1", so not too fiddly a job.

BugBear


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## Andy Kev. (18 Nov 2014)

Inspired by this thread and in particular by Cheshire Chappie's link to the Renaiscance Woodworker on the subject, I have just taken delivery of five new (new old stock) centre bits from these chaps:

http://www.oldtools.co.uk/tools/Wm_Ridg ... e_Bit.html

Not cheap but not ruinous either and they are in good order. So now I've just got to order some slip stones as per Bugbear's advice and I should be in business.


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## Cheshirechappie (18 Nov 2014)

Andy Kev.":2rxtxwyw said:


> Inspired by this thread and in particular by Cheshire Chappie's link to the Renaiscance Woodworker on the subject, I have just taken delivery of five new (new old stock) centre bits from these chaps:
> 
> http://www.oldtools.co.uk/tools/Wm_Ridg ... e_Bit.html
> 
> Not cheap but not ruinous either and they are in good order. So now I've just got to order some slip stones as per Bugbear's advice and I should be in business.




I have to admit that my only experience is with the old-type centre bits as shown by Shannon Rodgers on the Renaissance Woodworker video. I do have one of the newer sort as the Oldtools link, one of a batch of assorted bits from Ebay, but it's a poor rusty thing that I haven't cleaned up or tried out yet. It'll be interesting to hear impressions and experiences of the 'new' type centre bits.


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## bugbear (18 Nov 2014)

Andy Kev.":20z8fcs2 said:


> Inspired by this thread and in particular by Cheshire Chappie's link to the Renaiscance Woodworker on the subject, I have just taken delivery of five new (new old stock) centre bits from these chaps:
> 
> http://www.oldtools.co.uk/tools/Wm_Ridg ... e_Bit.html
> 
> Not cheap but not ruinous either and they are in good order. So now I've just got to order some slip stones as per Bugbear's advice and I should be in business.



Hmm. Those are really very different; the spur is very different (and harder to sharpen) and they *do* have a leadscrew.

BugBear


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## marcros (19 Nov 2014)

Those are the same as the ones that I bought- some were ridgeway some another pattern. 

Are the ones by the OP and subsequently described by others more like a forstner bit? I have seen these on a blog for a brace but never seen any for sale or in person.


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## AndyT (19 Nov 2014)

I have quite a 'selection' of bits including the centre bits CC described so well. I also have a set of bits as bought by Andy Kev and Marcros, made by Wm Ridgway. They are newer than the others; I'd guess at 1950s.
Maybe they were offered as more sophisticated than the old style but cheaper than full length auger bits?

Edit: Buck and Hickman listed them as 'new type centre bits' in 1935 and were still calling them that in 1953.
A couple of 1950s catalogues (Gardiner, Tyzack) call them 'fast cut' centre bits.


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## Cheshirechappie (19 Nov 2014)

The bits I was referring to are like these, illustrated on Chris Schwarz's blog - http://blog.lostartpress.com/2010/09/07 ... d-1-rimer/ - and are the sort covered by the 'Renaissance Woodworker' video mentioned earlier in the thread.

I found all mine on Ebay, using the search term 'brace bits'. They don't seem to come up as graduated sets of old-type centre bits very often (though I have seen the occasional offering), but the odd larger one does crop up for sale individually. Mine were accumulated by buying vintage assortments; they come up quite frequently, often consisting of a few 'old' centre bits, a few shell and nose bits, a few countersinks and sometimes screwdriver bits (well worth having a few sizes, especially the larger ones!) and the odd rimer. You sometimes see a brace and a roll of bits; it's worth scrutinising the bits carefully, since such sets rarely sell for big money, so you can put together a useful assortment of bits (plus some less useful) for not very much, with the bonus that you get a storage roll and a couple of spare braces, too.


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## bugbear (20 Nov 2014)

Cheshirechappie":2d2vo27b said:


> The bits I was referring to are like these, illustrated on Chris Schwarz's blog - http://blog.lostartpress.com/2010/09/07 ... d-1-rimer/ - and are the sort covered by the 'Renaissance Woodworker' video mentioned earlier in the thread.
> 
> I found all mine on Ebay, using the search term 'brace bits'. They don't seem to come up as graduated sets of old-type centre bits very often (though I have seen the occasional offering), but the odd larger one does crop up for sale individually. Mine were accumulated by buying vintage assortments; they come up quite frequently, often consisting of a few 'old' centre bits, a few shell and nose bits, a few countersinks and sometimes screwdriver bits (well worth having a few sizes, especially the larger ones!) and the odd rimer. You sometimes see a brace and a roll of bits; it's worth scrutinising the bits carefully, since such sets rarely sell for big money, so you can put together a useful assortment of bits (plus some less useful) for not very much, with the bonus that you get a storage roll and a couple of spare braces, too.



I think it is noteworthy that (prior to the dominance of auger bits) sets of brace bits are invariably (IME) mixed in type, as you say. It implies that the buyers knew, understood and exploited the strengths and weaknesses of each type, and used them appropriately.

BugBear


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## Jacob (20 Nov 2014)

The Ridgeway type (Oldtools) was standard issue in everybody's kit at 32mm (1 1/4") for Yale locks, so there are a lot of them about. It's still the fastest and easiest way to do it, hard or softwood makes no difference.


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## Jacob (20 Nov 2014)

bugbear":23ng9b6r said:


> ......
> 
> I think it is noteworthy that (prior to the dominance of auger bits) sets of brace bits are invariably (IME) mixed in type, as you say. It implies that the buyers knew, understood and exploited the strengths and weaknesses of each type, and used them appropriately.
> 
> BugBear


More likely that they simply didn't throw away the redundant ones on the off chance that they might come in handy. When they come up for sale it is likely to be after the previous owner's lifetime of not throwing stuff away often enough!
I've got drawers full of screwdrivers, never thrown one away and every now and then it proves to be a good idea - sometimes using an old one in a sacrificial way - hitting it with a lump hammer etc.


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## AndyT (20 Nov 2014)

It's maybe worth noting too that the older type of centre bit was still listed in catalogues in the 50s (which I feel isn't really very long ago) - and was cheaper than the 'fast cutting' sort. I guess it was the rise since then of the small electric drill, as the first power tool for any diy-er, that killed off the demand for braces in general and the bits to go with them. Hence compromises like the cheap flatbit, burning its way through anything in its path...


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## Jacob (20 Nov 2014)

Flat bits are excellent but they can't do what a centre bit can do (with or without lead screw) - which is to reverse the hole i.e. to wait for the point to just show and then drill from the other side.


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## Andy Kev. (20 Nov 2014)

Jacob":2dduk9un said:


> Flat bits are excellent but they can't do what a centre bit can do (with or without lead screw) - which is to reverse the hole i.e. to wait for the point to just show and then drill from the other side.


What I'm looking forward to finding out, once I've got them sharpened up, is whether or not the fact that they have lead screws means that they will split thinnish pieces of wood (as my normal augur bits do).


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## Cheshirechappie (20 Nov 2014)

Andy Kev.":1cwgyc73 said:


> Jacob":1cwgyc73 said:
> 
> 
> > Flat bits are excellent but they can't do what a centre bit can do (with or without lead screw) - which is to reverse the hole i.e. to wait for the point to just show and then drill from the other side.
> ...



Must admit, I don't know the answer to that one, either. The 'Renaissance Woodworker' video matches my experience with the older sort, in that they are much less prone to splitting thinner stock than twist augers (I wouldn't go so far as to say that they totally eliminate any possibility of splitting). It'll be interesting to hear any reports of performance of the newer type of centre bit with leadscrews.


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## Cheshirechappie (20 Nov 2014)

bugbear":27iy289e said:


> I think it is noteworthy that (prior to the dominance of auger bits) sets of brace bits are invariably (IME) mixed in type, as you say. It implies that the buyers knew, understood and exploited the strengths and weaknesses of each type, and used them appropriately.
> 
> BugBear



The Lost Art Press publication of 'The Joiner and Cabinetmaker' illustrates a Melhuish catalogue entry from 1912, showing a set of 36 bits. It consists of:

12 old-type centre bits, 3/16" to 1 1/4"
2 turnscrew bits, one forked
6 countersinks (2 each flat, rose an snail, 1 off 1/2" and 5/8" of each)
5 shell bits, 1/8" to 3/8"
5 nose bits, 1/8" to 3/8"
2 sash bits, 3/16" and 1/4"
3 rimers, 1 each square, half-round and hollow
1 Jennings pattern twist auger, 1/2"

Available in Black, price 10/6, Bright price 12/-, or Straw Coloured price 13/6. [That's shillings and pence - today those prices would be 52 1/2p, 60p and 67 1/2p. I wish!]

Interestingly, no bit roll is mentioned. Was the purchaser expected to make their own storage arrangements, or stung for the roll as an extra, one wonders?

I think that would be a fairly typical general joiner's kit; cabinetmakers and other specialist trades would have slightly different requirements. The Jennings auger is for dowelling, the rimers and countersinks for fitting screws to ironmongery and brassware (in the days before better standardisation of sizes), and the other bits for general drilling. Interesting that the sizes of shell bits and nose bits duplicate each other - it may be that one type or the other was preferred for different tasks, such as through holes, long-grain drilling etc. The sash bits are clearly for one main purpose. The centre bits are for larger, shallower holes, and the fact that the range of sizes is more comprehensive suggests that they were expected to do the bulk of drilling work. Also worth a mention is that very small holes would be produced by bradawls or gimlets, both non-brace tools. Most craftsmen would have at least two or three, and perhaps several sizes of both.

You don't come across many intact sets; hardly surprising, really. Most kits suffer wear and tear, losses and breakages over time (especially the smaller sizes of bit), and subsequent additions. I suspect also that most craftsmen would not have bought sets, but would have spread the cost by purchasing individual bits as the need arose, and made up their sets that way. That seems reflected in the contents of kits that come up for sale today, anyway.

The 1938 Marples catalogue uploaded to Toolemera by AndyT also lists sets of 24, 36 and 48 bits. I suspect they were available long before 1912, and some while after 1938.


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## AndyT (20 Nov 2014)

Cheshirechappie":3242ibcs said:


> It'll be interesting to hear any reports of performance of the newer type of centre bit with leadscrews.



Here we are then. One manky bit of thin softwood from the scrap box, held down to a backing board, and a 3/4" flatbit in a sixpenny brace:







Even right by the end, there is no splitting effect. (A bit of short grain has detached, but the wood is not split.)






Let's cut the end off and try again, using a bit with a leadscrew.

Going once:






Going twice: 






Gone!






I think the difference is clear. For an encore, a 1 1/4" centre bit in just enough wood:






Despite the wood already being split, a tidy hole is made.

To be fair, I also tried drilling into a stronger bit of 2x4, away from the edge, and found that the fast cut bit worked well, and was easier to use, as I did not need to press down. Indeed, the old style bit tended to choke up when it was about 3/4" down and I needed to remove it and pick resinous residues off the centre spike. I'd say that using the fast cut bit was much like using an auger bit, but potentially easier to manage than something 9" long and cheaper to buy (if bought new, back when they were easily available).


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## Cheshirechappie (20 Nov 2014)

Interesting! Thanks for that, Andy.

The conclusion is that neither 'older' nor 'newer' centre bits could definitely be said to be better. Both have pros and cons. In fairness, the need for large holes near the end of thin stock is not an everyday problem, though if the occasion did arise, having some older bits to hand would be a decided advantage. I suppose the best answer is to have some of each, especially if you drop on a few bargain assortments on Ebay or carboots!

PS - Nice little braces, those sixpenny jobs, aren't they? For smaller work that doesn't need too much grunt, I rather prefer mine to the heavier Stanley 10" ratchet job. Changing bits is faster, too.


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## Andy Kev. (21 Nov 2014)

Cheshirechappie":245gb2nj said:


> Interesting! Thanks for that, Andy.
> 
> The conclusion is that neither 'older' nor 'newer' centre bits could definitely be said to be better. Both have pros and cons. *In fairness, the need for large holes near the end of thin stock is not an everyday problem*, though if the occasion did arise, having some older bits to hand would be a decided advantage. I suppose the best answer is to have some of each, especially if you drop on a few bargain assortments on Ebay or carboots!
> 
> PS - Nice little braces, those sixpenny jobs, aren't they? For smaller work that doesn't need too much grunt, I rather prefer mine to the heavier Stanley 10" ratchet job. Changing bits is faster, too.


I had to laugh when I read that because it suddenly is an everyday problem when you decide to make a spaghetti measurer. I bought a book of ideas for making things from offcuts (name of author escapes at the moment and I'm not at home as I type) and therein is a spaghetti measurer. I decided to make one using only hand tools and the Augur for the biggest hole split some 3/8" American Walnut. So I ended up cutting some 1" walnut without problems and resawed it. Hence my new-found interest in centre bits.

Thanks to AndyT for the experiment. I have a cunning plan for eliminating the split with the screw type which I've just bought. Once my slip stones arrive and everything is sharp, I shall report.

Incidentally, for those who may be interested, here's a link to a German bloke's website where he talks about bits:

http://www.holzwerken.de/werkzeug/bohre ... eler.phtml

If there are any parts of it which are of particular interest, let me know and I will translate.


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## undergroundhunter (21 Nov 2014)

Would it not help to start the hole for the lead screw with a birdcage awl? This would possibly remove some of the wedging action caused by the lead screw. I haven't tried it, its just a thought.

Matt


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## nanscombe (21 Nov 2014)

You're almost getting to the point of having to drill a pilot hole for the lead screw, like a normal woodscrew :lol:


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## Sheffield Tony (21 Nov 2014)

When chairmaking it is not at all uncommon to need to drill a hole near the top of a leg, with a drill bit up to 1/2 the size of the wood itself. A pilot hole - I used 3mm for a 5/8 Irwin pattern auger - makes splitting caused by the leadscrew a lot less likely.


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## Cheshirechappie (21 Nov 2014)

Andy Kev.":afhje6ih said:


> I had to laugh when I read that because it suddenly is an everyday problem when you decide to make a spaghetti measurer. I bought a book of ideas for making things from offcuts (name of author escapes at the moment and I'm not at home as I type) and therein is a spaghetti measurer. I decided to make one using only hand tools and the Augur for the biggest hole split some 3/8" American Walnut. So I ended up cutting some 1" walnut without problems and resawed it. Hence my new-found interest in centre bits.
> 
> Thanks to AndyT for the experiment. I have a cunning plan for eliminating the split with the screw type which I've just bought. Once my slip stones arrive and everything is sharp, I shall report.
> 
> ...



Laugh? Well - yes - you can't do anything else, can you really! Absolute proof that in general, it's not a good idea to generalise!

Good luck with the spaghetti measurer. Let us know how you get on; it's bound to add to the general stock of knowledge.

Thanks for the link, too - Google Translate did a pretty fair job, except for the technical terms, but it was fairly easy to spot the dodgy translation and sustitute the proper word.

--------

Just a thought about using a pilot hole to prevent the leadscrew of a twist auger (or new-style centre bit) splitting stock - that will stop the screw pulling the bit into the work, so there will have to be a bit of axial force applied to the brace to get it to cut. That may not be such a bad thing, since the operator can determine the rate of cut, rather than having it set by the lead of the screw. For larger holes, which take quite a bit of grunt to drive at the rate set by the screw, that could be a definite advantage, especially in harder woods.


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## nanscombe (21 Nov 2014)

When drilling a pilot hole for a woodscrew you make it smaller than the actual screw so although there is less material to act as a wedge, and split the wood, there is still enough for the thread to bite into otherwise the screw wouldn't hold.

I would imagine that the lead screw would be the same.


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## Corneel (22 Nov 2014)

This thread was the inspiration for me to finally sort my small collection of centerbits. Mine really only fit in my sixpenny brace (lovely name), because they don't have a square taper but a flat one. I had to file some of them to make them fit better, but that's sorted now. All bits sharpened and I even made some holes in a block of wood for storage. 

Nice bits, but they are slow! But it is fun to be able to run that large 1 5/8" one with such a small brace.





No idea really if I will ever use them...


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## Andy Kev. (28 Nov 2014)

I had three goes with my newly sharpened 1 1/2" bit and split three bits of wood and that despite having drilled pilot holes. I reckon two things: a. the pilot holes were'nt quite big enough i.e. they might be need to be as big as the core of the thread where it is thickest at the top and while I got the cutting part of the bit to be seriously sharp, I couldn't get the scoring element more than routinely sharp. That's obviously a weakness of technique on my part but I wonder if inadequate scoring could contribut to splitting. The wood was very dry American cherry about 3/8" thick.


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## Jacob (28 Nov 2014)

I blame the wood - too thin. These bits are for bigger stuff. If you want 1 1/2" holes in thin stuff it'd be better to do it through a thick piece and then slice it up. And you shouldn't need pilot holes.


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## Phil Pascoe (28 Nov 2014)

As an aside - a spaghetti measure is pointless, every time you find the right sized measure, someone will buy spaghetti of a different length.


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## Cheshirechappie (28 Nov 2014)

Andy Kev.":2y9hxjw1 said:


> I had three goes with my newly sharpened 1 1/2" bit and split three bits of wood and that despite having drilled pilot holes. I reckon two things: a. the pilot holes were'nt quite big enough i.e. they might be need to be as big as the core of the thread where it is thickest at the top and while I got the cutting part of the bit to be seriously sharp, I couldn't get the scoring element more than routinely sharp. That's obviously a weakness of technique on my part but I wonder if inadequate scoring could contribut to splitting. The wood was very dry American cherry about 3/8" thick.



I think I'd try a pilot hole virtually the same as the largest diameter of the centre point. That would eliminate the wedging effect of the taper point. The problem would be holding the drill steady enough to get the outer spur to start cutting a true circle; if that circle could be marked out and 'started' (dividers with a sort of cutting gauge knife filed on, maybe, or a sort of very short trammel made up from a scalpel blade and a panel pin), you'd stand a chance.

Sadly, this is one instance when the 'old sort' centre bits would be in their element - the centre pin working like a birdcage awl cutting the fibres rather than wedging through them.


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## Jacob (28 Nov 2014)

Cheshirechappie":3bgmgey0 said:


> Andy Kev.":3bgmgey0 said:
> 
> 
> > I had three goes with my newly sharpened 1 1/2" bit and split three bits of wood and that despite having drilled pilot holes. I reckon two things: a. the pilot holes were'nt quite big enough i.e. they might be need to be as big as the core of the thread where it is thickest at the top and while I got the cutting part of the bit to be seriously sharp, I couldn't get the scoring element more than routinely sharp. That's obviously a weakness of technique on my part but I wonder if inadequate scoring could contribut to splitting. The wood was very dry American cherry about 3/8" thick.
> ...


If you are having to do all that it's simply the wrong tool for the job. Unless you are desperate and have no choice then you have to struggle!


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## Phil Pascoe (28 Nov 2014)

Yes. Just use a forstner and have done.


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## Andy Kev. (29 Nov 2014)

I agree with Jacob and phil.p in practical terms. It's pretty obvious from the results that I've been getting that I'm using this bit at the limit of its sensible applications. I also agree with Cheshire Chappie in that I bet there would be far less difficulty with the older style with its simple spike which as far as I can see (correct me if I'm wrong) has the function of simply holding the bit in place whiile the two cutting elements get to work.

I did start wondering yesterday why it had been thought necessary to introduce the threaded element.

All that said, it's fun experimenting and trying to identify what the limits of those sensible applications are. It's not as if I haven't got enough scraps of wood.

As an aside, all this fiddling about led me to a table of information which could be very useful (although it is not strictly related to hand tools; more to pillar drills). If you google Drill Press Speed Chart you should get to it.


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## Jacob (29 Nov 2014)

Andy Kev.":1dcctp9w said:


> ...
> I did start wondering yesterday why it had been thought necessary to introduce the threaded element........


It's just a simple improvement - it pulls the bit more positively into the work and makes it easier/faster. Earlier versions wouldn't have it as it would be too technically difficult to manufacture by a small workshop or blacksmith.


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## Andy Kev. (29 Nov 2014)

Jacob":2eurzw2e said:


> Andy Kev.":2eurzw2e said:
> 
> 
> > ...
> ...


That makes sense. Once I've got the scoring blade fully sharpened I should get the benefit of the thread being better able to do its job properly.


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## Andy Kev. (29 Nov 2014)

The bit went through 3/4" walnut like a hot knife through butter and with no pilot hole. So maybe the thickness of the wood is the limiting factor.


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## Cheshirechappie (29 Nov 2014)

Andy Kev.":2wmp37rd said:


> The bit went through 3/4" walnut like a hot knife through butter and with no pilot hole. So maybe the thickness of the wood is the limiting factor.




I think that's the case. The 'new type' centre bits are more than adequate performers in thicker stock where the pilot's wedging action won't split the wood, and the 'old type' cope with thinner stock better.

One question that does still hang a bit is how the 'new type' and 'old type' compare when hole size gets bigger. My Jennings pattern augers become hard work above about 3/4" in hardwoods, but the 'old type' centre bits perform quite well in larger sizes. It would be interesting to know if the same applies to the two types of centre bit, if anybody has both types in a range of sizes and would be kind enough to experiment a bit.


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## Jacob (29 Nov 2014)

My 32mm ridgeway type is like a hot knife etc. Fast and easy even in hardwood. Commonly used for Yale locks in doors 44 to 56mm. 
The big advantage of a ratchet brace is not only in cramped corners but also allows you to get max leverage - a to and fro push/pull with the brace at 90º to the arm, rather than having to go round the full circle. Could this be your prob - 3/4 bit and a brace without ratchet?


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## Andy Kev. (30 Nov 2014)

Jacob":7bj5x394 said:


> My 32mm ridgeway type is like a hot knife etc. Fast and easy even in hardwood. Commonly used for Yale locks in doors 44 to 56mm.
> The big advantage of a ratchet brace is not only in cramped corners but also allows you to get max leverage - a to and fro push/pull with the brace at 90º to the arm, rather than having to go round the full circle. Could this be your prob - 3/4 bit and a brace without ratchet?


No, it was a 1 1/2" bit and the brace has a ratchet. I think I'm content that too thin wood was doomed to split.


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## Andy Kev. (30 Nov 2014)

Cheshirechappie":3k0xg4if said:


> Andy Kev.":3k0xg4if said:
> 
> 
> > The bit went through 3/4" walnut like a hot knife through butter and with no pilot hole. So maybe the thickness of the wood is the limiting factor.
> ...


Experiments would be interesting. It could possibly lead to the ideal set of bits - by type and according to whether one is working with hard or soft wood - from 1/4" right up to say 3" plus.

For instance, what is the best point to stop with one type of bit and switch to another? 3/4" for hardwoods might well be a sensible point. I've got the 1/4" centre bit on the laptop as I type and I'm wondering what the justification for its existence is and then there's the matter of how fiddly it's going to be to sharpen it.


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## bugbear (30 Nov 2014)

Andy Kev.":1u7vftgf said:


> Experiments would be interesting. It could possibly lead to the ideal set of bits - by type and according to whether one is working with hard or soft wood - from 1/4" right up to say 3" plus.
> 
> For instance, what is the best point to stop with one type of bit and switch to another? 3/4" for hardwoods might well be a sensible point.



Returning, sort of, to the beginners tool kit thread, Hayward recommends (in the Junior Woodworker, 1953)

3/8" auger (for dowelling, I think)
snail counter sink
3/4 centre (the old style without leadscrew)
medium spoon or shell

His "The Complete book of Woodwork", 1955 has a slightly larger list; (*) means essential.

*1/4, *3/8, 1/2, 3/4 auger
*1/8 - *1/4 shell or twists bits for screw holes
Countersink *snail, rose
1/2, *3/4, 1" Centre bit
Turnscrew bit
Expansion bit

It looks like Hayward is very conscious of the importance of bit design w.r.t. hole size.

BugBear


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## Cheshirechappie (30 Nov 2014)

I only have one 'new-type' centre bit, a 5/8", so I've done a (rather limited!) comparison between a 5/8"Jennings twist auger and the two types of centre bit, both 5/8". All three bits were sharpened up and cleaned before trying them, the test piece was beech, and two braces were used, a 10" Stanley ratchet brace, and a 6" Skinner ratchet brace (I didn't use the old sixpenny brace for this one - the Skinner has a smaller sweep).

The Jennings auger was tried first, in the 6" brace. This proved too hard to turn comfortably, so a change was made to the 10" brace. This worked quickly, but needed a fair bit of turning power, though very little down-force. The bit was quite hot to the touch immediately after drilling.

The 'new-type' centre bit was tried, and needed a bit less force to turn using the 10" brace. A little down-force was needed, and a stop had to be made to clear clogging before resuming. Speed of cutting was marginally less than the Jennings auger. Again, the bit was hot to the touch on finishing.

The 'old-type' centre bit was very easy to turn in comparison with either of the others; it was even easy with the 6" brace. However, it needed significantly more down-force to keep it cutting, and was slower to complete the hole - about twice the time of the other two. The bit was warm on completion, but not as hot as the other two.

All three holes were clean and untorn on the diameter when finished, and all three measured accurately 5/8".

Conclusion - the newer centre bits and Jennings augers work faster, with less downforce, but need far more turning force than the older centre bits. All are capable of giving clean holes across grain in hardwood (beech).

Has anybody got any selections of larger bits, so as to add more data as it were?


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## bugbear (30 Nov 2014)

Cheshirechappie":2g6rxe2v said:


> Conclusion - the newer centre bits and Jennings augers work faster, with less downforce, but need far more turning force than the older centre bits. All are capable of giving clean holes across grain in hardwood (beech).



Interesting; those properties might fit very well with the small sweep braces that were
dominant before the widespread introduction of "American" (i.e. steel, not wood)
braces.

BugBear


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## nanscombe (30 Nov 2014)

Of course, if the lead screw were longer than the stock in question was thick, it might be possible to drill a pilot hole larger than the lead screw and allow it to bite into a piece of scrap wood beneath the stock and pull the drill through.


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## Billy Flitch (30 Nov 2014)

I don't know whether this will add to the groups knowledge on center bit or not but I`LL add it any way.
I`ve never heard of the leading screw I`m not saying the term is wrong just I`v never heard of it I`v always known this part of the bit as the worm and it is the worms job to pull the bit through the piece.
Things to note about a center bit it only has one spur and only cuts on one side of the bit the opposite side to the spur, its easy to see if you are drilling square on to the piece as when the spur comes into contact it should form a complete circle if it does not the you are not drilling square on.
I do confirm what Jacob said that most Carpenters carried a 1 1/4" center bit for boring for a yale lock in a front door. The yale locks are usually fitted at chest height on a door and this does not lend its self to a good purchase on the bit but no problem as the worm is there to pull the bit through the door, wait for the worm to show then come at it from the other side.

As an apprentice I worked with Shipwright loftsmen and they would use the old style center bits for boring through 1/4" thick battens without splitting the piece the would refare to the center point of the bit as s brad or sprig bit point.

Shipwrights fitting wooden decks on boats would also use old style center bits but they would have the center point ground off and a short dowel about 3/8" dia and 1" long welded on to the center point, fist a 3/8" hole would be drilled in the plank and through a frame and then the center bit would be used to drill a counter sunk hole to allow the plank fitting to be sealed latter with a dowel.
I have often seen these bits included in sets over on e-bay and wondered if people knew what they where for, the brad point and the dowel where both being used for the same purpose to keep the bit centered in use.
I don't know whether this adds any thing to any ones knowledge on center bits but that's it.


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## Andy Kev. (30 Nov 2014)

Here's some wholly unscientific data from a bit of fiddling around I've just done (all bits newly sharpened and used in a 10" brace):

Bit Size 1/4 Wood Thickness 1/8 Distance centre of hole to edge of wood 1/4 Result: Split EC

Bit Size 1/4 Wood Thickness 1/8 Distance centre of hole to edge of wood 1/2 Result: OK EC

Bit Size 3/4 Wood Thickness 1/8 Distance centre of hole to edge of wood 1 1/2 Result: Split EC 

Bit Size 3/4 Wood Thickness 1/8 Distance centre of hole to edge of wood 2 1/2 Result: OK EC

Bit Size 3/4 Wood Thickness 3/8 Distance centre of hole to edge of wood 1 3/8 Result: OK ABW

Bit Size 7/8 Wood Thickness 5/8 Distance centre of hole to edge of wood 1 Result: OK ABW

Bit Size 1 1/2 Wood Thickness 3/4 Distance centre of hole to edge of wood 1 5/8 Result: OK ABW

EC = European Cherry ABW = American Black Walnut

There are no conclusions which can be made from this but it would appear that you can get reasonably close to an edge with a largish bit provided that the wood is thick enough. That is hardly news. I was a bit surprised though at the 1/4" bit causing a split and needing to be relatively far from the edge of the 1/8" wood to deliver good results. I got identical results with a colt 6 mm HSS twist bit used in an eggbeater drill.


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## Cheshirechappie (2 Dec 2014)

Billy Flitch":u4u0yb2m said:


> I don't know whether this will add to the groups knowledge on center bit or not but I`LL add it any way.
> I`ve never heard of the leading screw I`m not saying the term is wrong just I`v never heard of it I`v always known this part of the bit as the worm and it is the worms job to pull the bit through the piece.
> Things to note about a center bit it only has one spur and only cuts on one side of the bit the opposite side to the spur, its easy to see if you are drilling square on to the piece as when the spur comes into contact it should form a complete circle if it does not the you are not drilling square on.
> I do confirm what Jacob said that most Carpenters carried a 1 1/4" center bit for boring for a yale lock in a front door. The yale locks are usually fitted at chest height on a door and this does not lend its self to a good purchase on the bit but no problem as the worm is there to pull the bit through the door, wait for the worm to show then come at it from the other side.
> ...



I've seen the occasional 'pilotted' centre bit on Ebay, though they're fairly rare, I think. The 1938 Marples catalogue on Toolemera lists them in a range of sizes, but they could only be ordered by the dozen, and the purchaser had to specify the pilot diameter, which suggests they were only made to order. Nobody really needs a dozen of them, so it's understandable that people made up their own to the sizes they needed.


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