Making hollowing tools

[Phil Pascoe]

I've been trawling evil bay, looking for ideas for when I come to make my own hollowing tools. Is there any merit in using hexagonal bar? I can see the theory, but has anyone tried this?

 

[Vic Perrin]

Personally I have always used Square Section bar which gives you that extra stability on the tool rest particularly when you are doing a deep hollow form.

Vic

 

[Phil Pascoe]

Thanks Vic, I can see this but is there any point in going for hexagonal bar - you've still got a flat underside, the downside being that pressure is slightly off centre if the tip is skewed, the upside being that the tip can be skewed and still have support. For the cost of making them I might make both, the main cost being the tips.

 

[Vic Perrin]

Thanks Vic, I can see this but is there any point in going for hexagonal bar - you've still got a flat underside, the downside being that pressure is slightly off centre if the tip is skewed, the upside being that the tip can be skewed and still have support. For the cost of making them I might make both, the main cost being the tips.

As you say Phil the tools cost very little to produce and an hexagonal bar might prove to be ok.

I don't know whether or not you have made any yet but I can assure you that if you haven't you will be well impressed on how they cut.

God knows how many different turning tools I have, but since making these carbide tipped tools they seem to have become my first choice especially for roughing out and end grain hollowing.

I have also made some carbide tipped tools for my Lyle Jamieson Hollowing Rig and have really improved how that system cuts.

Vic

 

[duncanh]

Every tool I've made has been round bar except one which was square. I always use the round ones for hollowing. They give me far more control and allow me to rotate the bar and ease into the cut. More often than not I will rotate the tool during use to ensure the most efficient cut.

The square tool I made is useful for roughing down the outside of logs but that's about it.

 

[Phil Pascoe]

I can see the beauty of the solidity of a square bar when roughing and maybe a square bar with an angled tip for taking the final light cut, but I can see that the manoeuvrability of the round bar would be advantageous in other situations. Anyone going to disillusion me?
I think when the time comes I'll just make and try everything.

 

[chipmunk]

Hi Phil,
I have made my own tools in both round and square, as well as having a Big Brother with a round shaft.
I like HSS cutters rather than TCT ones - they're easier to make and sharpen IMHO - but each to his own.

Provided the square shafts have rounded corners it really makes little difference in use. However, it does help with reminding you of the orientation of the cutter when it's lost inside a vessel out of sight.

These are all mild steel and bending the swan necked tools is pretty straight forward if you heat the point of bend to dull red and then tweak it round - remeber to have the cutter in line with the shaft to prevent big turning moments in use.

I also have some square shafted tools with the cutters mounted at 45 degrees to the edges for shearing cuts like the Sorby tool here...

HTH
Jon

 

[Phil Pascoe]

Brilliant! Thank you. How do you find the angled tipped one to use?

 

[chipmunk]

Phil,
The angle tipped tool is very good for finishing cuts but it's not a heavy-duty hollower.

For bulk hollowing you don't want too broad a cutter as it can be grabby. The Sorby No 8 cutter style are my favourites for real hollowing scrapers in smaller sizes and the No 4 bullet cutter in larger sizes. http://www.stilesandbates.co.uk/browse.php/section/6541/level/4

I used to buy these but I now make them from 1/8"x5/8"x4" HSS toolbits from ArcEuroTrade... http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/High-Speed-Steel-Toolbits

Cut with Dremel cut-off tool, drill a 5mm hole with a high quality spade TCT tile drill and shape flat on benchgrinder platform. As an alternative to drilling you can cut a 5mm slot in the back with a Dremel or an angle grinder.

HTH
Jon

 

[Phil Pascoe]

Thanks - I've stored those links. It'll be a while yet before I get to making them, but I like to get the thinking done first. It's cheaper that way. I'll post them when I'm done.
Phil

 

[robinthebevel]

Hi Jon... and everyone else...

New to turning and brand new to this forum.

Just wanted to say a quick thank you for the link to the tool steel supplier! Been trawling the internet for ages before I found your post.

Cheers!

 

[Melinda_dd]

As someone who hasn't used a hollowing tool, what is the difference between a hollowing tool and a Robert sorby multi tip scraper tool...

Please dont laugh
..never even touched a hollowing tool

 

[Random Orbital Bob]

If the Sorby tool in question has a long and robust stem then not necessarily anything other than perhaps a swan/goose neck for the difficult access in the upper "corners".

Hollowing tools come in a variety of shapes but the access and long hang over the toolrest are two unavoidable problems that usually drive the design in the direction of chunk (handles often as well as stems) and swan necks.

The tips include quite a range.

 

[bogmonster]

First off, yes, certainly have a go at making your own. Simple hollowing tools can be very easy to make. Hexagonal bar is almost always tool steel of some variety. Unless you are going to incorporate the cutting edge into the same steel as the shaft then I would avoid unless you really know what you are doing and even then I would still avoid.

New tool steel stock is supplied annealed. Unless it is an exotic such as an air hardening steel then it is reasonably easy to work but there will be limited advantage to it over mild steel in its annealed form. You would need to harden and then temper the steel to get any real benefit from the tool steel. This is difficult to achieve in the home workshop for anything other than ends of tools or small pieces. Certainly very difficult for a 2 foot tool shaft. The implications of screwing up can be dangerous if you end up with hardened sections that you have not tempered as they can shatter (this is why you should never sharpen files and use them as chisels on a lathe as they are too hard and brittle).

By all means have a go at making your own cutting tips. A piece of ground flat stock (usually O1 or similar steel) is a good place to start. Can be worked with hacksaw, file and good HSS drill bits. Can be hardened with fire bricks and a good propane torch or better still a MAPP gas torch. Quench to harden in oil for GFS or O1. You can temper in your kitchen oven but make sure you use an accurate oven thermometer and I recommend you quench in veg oil if this is your plan. There is loads of info on the internet on this topic.

This link has some tooling I made from GFS (only the dies, the frame s MS, and in these pics pre-hardening and tempering) - use the back and forward arrows to see a couple of other pics. These are 1" x 2" x 4" so too big for most people to tackle at home without special equipment.

https://www.flickr.com/photos/33795885@N04/14175729906/in/photostream/

BM

 

[Walney Col]

There's some great pointers in this thread, thanks everyone.

 

[chipmunk]

Hexagonal bar is almost always tool steel of some variety.

That's a bit misleading IMHO. Mild steel hex bar is very readily available for making nuts and bolts.

Jon

 

[bogmonster]

Yes, I'm sure you are right Jon. Appologies for any confussion caused.

 

[finneyb]

The easy way is use a piece of 6mm Square tool steel http://www.rdgtools.co.uk/acatalog/Squa ... -hss-.html
Put in the end of a 20mm carbon steel rod - mine's about 2ft long - with an extension handle for deep hollowing.

Snap the tool steel to length - score with a file and snap with pliers - use eye protection
Grind the end that's going into carbon steel approx. round.
Drill end of carbon steel and fix tool steel with superglue - if you need to change the tool steel heat breaks the glue bond.
Grind the cutting edge as you desire.

Brian

 

[duncanh]

I still don't see the need for hex or square bar. Round is much more controllable for getting a better finish. Almost every hollowing tool on the market is round.

 

[xraymtb]

Would square bar not give better control in circumstances where the cut is being made to one side? For example if the cutting tip projects at an angle sideways this will exert a rotational force on the bar which the square bar counters better?

I have some DIY carbide tools and square bar makes keeping the cutters level easy (although makes a shear cut with the cutter at 45 degrees much harder)