Drill press for cutting 16mm holes

[user 42626]

Good evening everyone, I'm normally actively supporting Hegner scroll saw users elsewhere on this site but I'm here seeking some advice with equipment and tools for a specific metalworking task.
Early next year i plan to make a number of linkages from aluminium flat, approx 6 or 7mm thick 25mm wide, 80mm long.
Thats the easy bit.

I need to drill 2x 16mm holes in each one so i can press fit 2x 16mm bearings. I'll obviously measure these more accurately with digital verniers or similar.
The holes need to be a snug fit.
Is it possible to do this with a good drill press such as a meddings, fobco, tauco etc. if it has a good quill and little float then can i attempt it with something like a 15mm or 15.5mm bit.
I don't mind buying the drill as its a good tool for many of my normal straight forward jobs anyway and i appreciate the quality of old ones.
Also I can't justify a mill drill as they're pretty big and expensive.
I've tried all my local engineering firms for the work but as usual a lot of air gets sucked in and big prices mentioned including £50 to £80 upwards just for set up. I've even been attempting this task with a small privateer for over 3 months and still no results.
I could need more than a hundred long-term but at this stage just knowing if its possible will help
Many thanks

 

[ChaiLatte]

I need to drill 2 x 16mm holes in each one so i can press fit 2 x 16mm bearings.

Is the distance between the two holes important? If so, how will you assure that distance is correct if using a drill press?

Do you have a drawing of what you are trying to produce? A £50-80 set up charge is reasonable. What is the cost per piece after that?

You will not press a 16mm diameter bearing into a 15.5mm hole in aluminium.

A 16mm-ish diameter standard twist drill is not suitable for making a bearing-quality hole in 6mm thick aluminium. With care, and a few smaller pilot drills in advance of its use, it might make a barely acceptable hole in circa. 25mm thick alminium.

If I were forced to do this on a drill press instead of a mill, I would invest in a hardened drill guide maybe 20mm thick that has two 16mm diameter holes in it the correct distance apart. For the most accurate 16mm hole, I would use a Rotabroach cutter in conjunction with that guide.

Loctite make a 'bearing fit' retaining compound. You might do well to read the datasheet as it will tell you the amount of oversize it can accommodate.

 

[Chief Sawdust Maker]

I would suggest it would be a good job for a small CNC shop
I make a similar project out of 12.5mm oak with 20mm holes bored through., using a roughing cut and finishing cut
Most CNC's even low end should be able to hold a tolerance, but would agree with a previous post ref Loctite and tolerance regarding the hole size.
Small jig with a locator and clamp would speed up the process and ensure consistency

Drop me a pm if you like happy to discuss further

D

 

[user 42626]

As an experiment i took the original link I'm wanting to replicate. Its nylon but i drilled a new hole with a 16mm step drill using my makita hand drill, yes don't laugh.
The bearing was an amazingly perfect fit, i ran the drill very very slow and had to stop half way and drill from the other side but yes it was a very acceptable first attempt without any specific tools.
Yes i know I'm entering the realm of accuracy and precision but I'm happy just experimenting with this heath robinson approach. I get that metalworking can be a very concise and accurate business.
Forgive my somewhat blaise approach, i guess i was hoping for a simple "try one of these and do this type thing"
I'll be buying the drill anyway as its useful enough.

 

[user 42626]

Yes its not in the centre, i just drilled to see what would happen. I imagine the aluminium will be somewhat less forgiving

 

[Inspector]

If you have a solid drill press (not a dinky thing one person can pick up) and drill in a few steps without moving the part until about 0.3mm under the bearing size and then use a reamer with lubricant you might get a decent hole to press the bearing into. You should also be using a micrometer and at least some telescoping hole gauges to do your measurements with. A calliper, even digital, is not accurate and repeatable enough for the task.

Pete

 

[user 42626]

If you have a solid drill press (not a dinky thing one person can pick up) and drill in a few steps without moving the part until about 0.3mm under the bearing size and then use a reamer with lubricant you might get a decent hole to press the bearing into. You should also be using a micrometer and at least some telescoping hole gauges to do your measurements with. A calliper, even digital, is not accurate and repeatable enough for the task.

Pete

Thanks Pete, I'm possibly picking up a 1940s proper drill press, its meant to be in excellent condition with no play at the quill. Definitely a nice old thing even if just for mediocre tasks most of the time. Its very rare i would need to operate on such precise tasks often but it's interesting to see if i can do it without having serious amounts of specific equipment

 

[ChaiLatte]

...I drilled a new hole with a 16mm step drill...

You might have hit a winner there. If the length of the 16mm diameter bit of the step drill is enough to go through the full thickness of the aluminium, it should work.

If the 16mm part is too short to go through, it might not cost all that much to have the bigger diameters above the 16mm portion ground down to 16mm so you achieve the depth you need.

The smaller steps of the drill that go through ahead of the 16mm finishing diameter do a good job of creeping up the size, and being all joined together, they are surely concentric.

The difficulty with a large twist drill on thin material is that the point/centre will exit the material almost before the outside of the drill enters the material. That is not good for accuracy or assuring diameter. The step drill bypasses this issue, so you have done well by your experiment.

 

[user 42626]

You might have hit a winner there. If the length of the 16mm diameter bit of the step drill is enough to go through the full thickness of the aluminium, it should work.

If the 16mm part is too short to go through, it might not cost all that much to have the bigger diameters above the 16mm portion ground down to 16mm so you achieve the depth you need.

The smaller steps of the drill that go through ahead of the 16mm finishing diameter do a good job of creeping up the size, and being all joined together, they are surely concentric.

The difficulty with a large twist drill on thin material is that the point/centre will exit the material almost before the outside of the drill enters the material. That is not good for accuracy or assuring diameter. The step drill bypasses this issue, so you have done well by your experiment.

Thankyou for the support.

 

[Inspector]

You might want to read through Ttrees thread about boring holes. He went through a lot to stiffen up a drill press. You won't be working it as hard but might have to deal with repositioning if the bits and reamers you need are not all the same length.

https://www.ukworkshop.co.uk/thread...ce-for-boring-what-angle-to-make-jaws.135568/
Pete

 

[user 43593]

The holes need to be a snug fit.

What sort of tolerance will you work to? I have cut many things in aluminium up to T 6061 at 20mm thick. What you want done is relatively trivial on a CNC machine. I have a hobby machine that I have worked on and fettled to give me tolerances of ± 0.001". I have an example image that is 6mm thick 6061 and I was using a relatively poor grade of endmill. I now have a supplier of decent 0 flute aluminium cutters so the edges look far better than in the image.

 

[Spectric]

I need to drill 2x 16mm holes in each one so i can press fit 2x 16mm bearings.

You say two bearings and it is a linkage, what sort of operational speed? Is this driven or just a linkage for control, ie a lever ?

The direction I am thinking of would be much simpler and offer self alignment, have you ever used Rose bearings (rod end bearings) ? These come in many sizes and load ratings, using ones with a female thread would allow you to just use a threaded rod to connect the two together to form a linkage, depending on the required length I have used one with a long male thread that I just screwed into the female with a lock nut to produce a linkage for a machine repair.

 

[user 42626]

An interesting idea but the link is for use on a scroll saw and will be exposed to constant wood dust. Rose joints don't seal well enough to prevent dust entering when compared with the standard roller bearings.
Thanks for the suggestion though

 

[bp122]

Not sure how many you need and if you need to make changes in between, but I'd suggest a different direction.

We use this company for laser cut metal parts called Laser master for work (AI robotics). I think they are based somewhere in the far south east of UK. Quality is great and prices are actually decent.

If you put all your bits into one order and ask them for a quote, they might give you a price which, considering your time, cost of materials, cost of a drill press, frustration and uncertainty of accuracy (or lack thereof), might be reasonable.

If you already have the material and want to do it yourself, no worries.

You can also try a waterjetting service but their finish is not great for bearing fits.

 

[Phil Pascoe]

https://www.lasermaster.co.uk/
Just up the road from me?

 

[chaoticbob]

Hi galvernisednuts. I've done a fair bit of this sort of thing (home workshop, not pro) so I'll contribute my 2p worth.

Bearings are (in my experience) either spot on in their external diameter or slightly under, by which I mean plus nothing to minus maybe 3 microns at this sort of diameter. I'm not sure what you mean by a press fit (I suspect you may mean what I'd call a push fit, ie doable by hand rather than needing a press), but whichever you need to make the hole somewhere between 5 and 25 microns smaller on diameter than the bearing. These are ballpark figures from my own experience.
That sort of accuracy isn't achievable by drilling. Well not by me for sure! I think that the reason you got away with it in nylon is that nylon tends to expand as you drill it and when you remove the drill the hole 'relaxes' somewhat giving an undersize hole.
Reamers normally cut slightly oversize, so what I'd do in your circs is to drill slightly undersize (say 15.7mm), ream 16mm then use a bearing retainer compound.
Bob.

 

[AES]

Well, I'm with Inspector (Pete) on this one (and his suggested thread by Ttrees).

We're miles (almost measured in thousands galv nu!) away from each other, and anyway it's sold now, but for a drill press, unless you find a GOOD S/H Meddings, etc, it does NOT have to be an old machine.

The Rexon drill press I've just sold was a very respectable machine (bench mounted) sold a short while back as I need to move house and give up my shop (health).

Made in Taiwan it cost about 450 Euros about 20+ years ago. I fitted a better chuck (Rohm, about 100 Euros then) and run out was less than half a thou (Imp). It had a standard capacity of up to 13mm but being MT, it could also handle MT twist drills up to 20mm (no chuck). It had 10 or 12 speeds (I forget) and the only downside was changing belts to change speeds (no geared head), but it did have rack & pinion lowering/raising table. No idea what that set up would cost now, but there must be some decently-made and decently-priced stuff of similar capability out there somewhere, surely!?

For the job described by galv nu, I think CNC would be much too expensive unless many hundreds off of the same linkage are needed.

Myself I'd use a decent quality MT twist drill straight into the quill (no chuck) of about 15.5 mm dia or a little larger if you can find it. The final fitting of the hole to suit the bearing would be by means of reamer - hand reamer, again unless many hundreds off are required. Final fitting would be by hand anyway - to achieve a fit where the bearing CANNOT be pushed in by hand but "eased in" by means of a suitably sized drift lightly tapping with a hide or plastic mallet. Part of that hand fitting would also use Loctite bearing retainer - I use No. 603. NOTE: The above drift is sized to fit the OUTER cage of the bearing. Could be hardwood but flat-faced copper preferred.

The only "problem" is the lateral distance between the two bearings (AND getting them both on the same centre line)!

Not as difficult as you probably think if you have a surface plate and a height gauge (digital or vernier) plus a Vee block. If you don't have/can't afford a surface plate (I never could!), then a marble slab or a piece of thick plate glass will be good (kitchen fitters or shopfitters - offcuts). I got my bit of glass shelving from a shopfitter and dropped "a few quid" extra for him to bevel off the edges. Mine's about 10 inches wide by about 15 inches long. Again just sold it.

For a drilling template choose a piece of steel (preferably - could be HARD ali if you must) of at least 5 or 6 mm thick and decide the size of hole you'll need - less than the web width of the above MT 15.5 mm drill you'll be using. Saw and file one dead straight edge and one end at exactly 90 degree (also dead straight).

Set up the template vertically on the glass (that's what the Vee block is for), set out the centre line of the two holes, then stand the template vertically on it's square end and mark out the position of the two holes where they cross that centre line.

Off the surface plate (if it's glass!) centre MARK the template (NOT yet centre punch!) using a magnifying glass/jeweller's loupe/similar (if you're half dead like me)! Follow up with a light indent from a FRESHLY GROUND centre punch.

Taken carefully there will be no realistic/important difference in accuracy between your hole positions made as above and CNC. Yours will - maybe - take longer but WILL also be cheaper!

The only worry now is to ensure drilling template lines up EXACTLY on the actual job. If you need to produce several of these linkages at one go, I'd recommend the use of clock makers taper pins (as used for hold two or more plates of a clock frame together for initial hole drilling). Accuracy there is even more important than for scroll saw linkages.

HTH and hope none of it is teaching granny to suck eggs. The method/s described above are certainly old-fashioned but taken carefully, they definitely DO work and though taking longer than CNC, are also cheaper than CNC!

Cheers

 

[Chief Sawdust Maker]

Have you got a target price in mind for the item?

I often do small run jobs on my CNC for people at very competitive prices particularly during periods when my usual work is short, its better for the machine to be running and covering costs than sitting idle.
The cheapest job are those where I receive raw material or a part finished part and just carry out the CNC operation and return to the customer for example it adds to my time and therefore the cost if I have to cut stock to rough length or carry out a complicated or in depth deburring process
I agree with a lot of the previous posts that it could be done on a drill press using a combination of drills reamer and bearing lock and yea its very satisfying to do things the manual way and to fettle to get the items right
A lot of British industry feel away in the 80's due to doing things in the old way. I remember watching a TV documentary where a very successful and respected business man Sir John Harvey Jones spent time with a manufacturing company, the company wanted to increase production, reduce wasted time and improve quality, they seemed happy to spend a short time making the part using dated processes and then spend variable amounts of time fettling and sometimes scraping parts to get them within tolerance.
Once the scrappage and fettle time was costed into the parts it was clear that the existing methods and costs were both inaccurate and by using the most modern method available for production they were actually saving money and time over the previous method.

Hope you get sorted and my offer of helping still sands, (time for breakfast ramblings of an insomniac)

 

[user 43593]

Found an image of the endplates that I cut. The large hole was cut helically. The second image shows the lead screw endplate in situ on friend's CNC machine which had hard plastic endplates.

 

[Fergie 307]

Undoubtedly the correct way to do this is on a mill and with a proper boring tool. You might well be able to use a boring tool in a suitable heavy duty pillar drill. You really should use a boring tool for repeatable accuracy to the tolerance required for a good bearing fit.Things to bear in mind are the rigidity of the table on the machine. People rightly emphasise the importance of a good quill with no slop. The table is equally important, no point in a rigidly mounted tool if the work itself can move about. And for aluminium you will definitely need a lubricant. Paraffin is probably the best, and easily obtainable.