Sensitive Drill Attachment

[Mcgyver]

I have a sensitive drill press with a stationary spindle.

That created a mental image of drill press with a spinning head, column, work and table.

Jason, the key to small holes is a good drill, good material concentric drill and sensitivity.  As Dave points out, speed doesn't much matter.  (watchmakers make the smallest holes and rarely would go more than 1500-2000)  Those attachments are ok and hopefully JAcobs is still putting out high quality chucks (I've a 0 and it is very good), not as a good as a balance table like below, but certainly better than a large heavy quill and unless going really small, may be all you will need.

Dave, I've got one of the Levin drilling tailstocks, a mechanical marvel.



Also a few shots of a simple table that appeared in Home Shop Machinist magazine ages ago.  Its counter balanced and works very well. Highly recommended.

[steamer]

Sweeeeeet rig McGyver!    I would love to try that out and see what all the talk is about.'


Dave

[Krypto]

This isn't an equipment attachment, but here's a quick video of my Dumore sensitive drill press drilling a 0.3mm hole in a 3D printer nozzle.

<a href="https://www.youtube.com/watch?v=tCnfdj-l_yM" target="_blank">http://www.youtube.com/watch?v=tCnfdj-l_yM</a>

I also own a Cameron sensitive drill press.

Below should be a scope picture of a factory nozzle beside one I drilled (0.2mm->0.3mm).  Looks close and it worked great.

[Roger B]

At the more basic end of the scale this is a 0.3mm hole drilled in 2mm thick brass with my Proxxon TBM220. The chuck would not hold a 0.2mm drill.

https://www.proxxon.com/en/micromot/28128.php

[Admiral_dk]

All the smallest sizes I do ( so far 0.6mm ~24mil = 0.024") - is on the Table CNC @ Work. My experince here is that the higher the RPM the smaller the chance of a broken Drill-Bit (not that it happens very often anyway).
The slower the RPM or Feed -> the more the Bit wanders before starting the Hole (@ the surface).
But as mentioned - it is not required to be fast ....

Roger - I do not know how small you can get them (I see 0.1mm ~3.9mil=0.0039") - but have a look after 1/8" / 3.175mm shank VHM Drill-Bits for PCB manufacturing. The cheapest are from AliExpress, are ok - the Best are from a few German Manufactors (that I can't find right now) ....   

Per

[steamer]

All the smallest sizes I do ( so far 0.6mm ~24mil = 0.024") - is on the Table CNC @ Work. My experince here is that the higher the RPM the smaller the chance of a broken Drill-Bit (not that it happens very often anyway).
The slower the RPM or Feed -> the more the Bit wanders before starting the Hole (@ the surface).
But as mentioned - it is not required to be fast ....

Roger - I do not know how small you can get them (I see 0.1mm ~3.9mil=0.0039") - but have a look after 1/8" / 3.175mm shank VHM Drill-Bits for PCB manufacturing. The cheapest are from AliExpress, are ok - the Best are from a few German Manufactors (that I can't find right now) ....   

Per

Per    those are the style I run in the Levin    AS long as you don't mind the country of origin, they're cheap as chips...\

Dave

[Roger B]

I do have some reinforced shank 0.2mm drills that I used for the injection nozzles as standard 0.2mm drills were not rigid enough. These were used at 2000rpm with a lever feed tailstock on my Hobbymat.

[Admiral_dk]

Man - those are Very Long Shafts 

.... but other than that - that is the style I meant ....   

Per

[mikehinz]

Just a few comments to add to the information. 

Some time back I purchased a Royal sensitive drill attachment and put a Cushman 1/8" keyless chuck on it.  It turned out to be a very handy, very accurate device for the small holes that I drill. 

Most of the comments above are exactly correct, particularly when drilling really small holes, smaller than #80 / .0135".

My experience is only with drills #80 and larger.  What I've found is that down to #60 / .040" I can almost always successfully drill holes using my Bridgeport quill with a small Albrecht keyless chuck. And I use a small Albrecht chuck in my lathe (a 13" x 40" import) tail-stock and can successfully drill down to #60 without using the sensitive drill attachment.  I think the key(s) to the process are 1) high rpm, 2) new or perfectly sharp drills, 3) A small dimple made with a small center drill 4) backing out and clearing chips very often and 5) Use some good quality cutting fluid and apply it frequently.

Smaller than #60 I always use the sensitive drill attachment secured in a .50" collet and I recently drilled several .020" holes using the sensitive drill attachment.  All the above rules apply when using the attachment.  I find that drilling with the Bridgeport is extremely nice as work holding is easy with the vise, or with a fixture plate or with whatever jigs are necessary.  Accurate positioning of the hole is so much easier vs any other method I've tried.

Hopefully this is information is useful.  If I ever have to drill anything smaller than #80 I think I'd look seriously at the various watchmaker techniques mentioned above.

Mike

[Chipswitheverything]

The Pillar Tool sensitive drilling attachment, as per my example here, has been made by many, of course, and it works extremely well.  When Geo. H. Thomas designed it, he opted for speeds of 1200 and 2200, not that fast, but he states that the very high theoretical speeds for tiny drills are not really achievable in such a machine made in the home workshop, nor very necessary. 
 I have used my drill to make many hundreds of holes at 10 thou diameter ,0.25 mm., for drilling pitot holes in stainless steel and cupro nickel hypodermic tube , which was laid under the carbon fibre top skin of small propellor blades ( made by an aerospace company ) used for research into high speed airflow at my place of work.   A CO2 cylinder was coupled to the tubes as the drilling was done, and the swarf ejected by a burst of positive pressure as the hole was drilled.   I have also used the drill head rigged up with a temporary scheme of bracket and motor, attached to the fixed spindle of a very large radial arm drilling machine, to work over the surface of much larger aerofoil test wings.   The sensitivity of the action on the GHT drilling head is a very great help in controlling the feed of these small drills.  Dave

[JasonP]

The drill attachment arrived. The Chuck is a Jacobs #0, made in the USA, and very nice quality. The drill attachment itself doesn't have any markings on it. The vendor claimed it was a Jacobs #55, but I can't find any reference to it on the internet. The tool seems to be very well made, with a round edge plastic disk that may have been knurled at some point but is now mostly smooth. There is a brass coloured end cap as seen in the pic, and the mechanism is a very precise fit with no play. The bearing tiny bit rough in the hand, but I'll stick in on the mill today and see how it feels. I'm trying to resist the temptation to disassemble, clean and lube, 'cos that's another rabbit hole.
Oh, and it didn't come with a chuck key, so it's a trip to Grainger on Monday to pick one up 

[Admiral_dk]

Looks good and as long as you can get another Key -> All is Well     

Per

[JasonP]

Well, not so good. I put it in a collet on the mill and clocked it to make sure it's concentric. Nope. TIR is 0.01, which on this is horrible. I popped the chuck off the taper and took a series of measurements and the shaft that engages with the chuck is bent. The 1/2 shaft in the collet has less than 2 tenths runout, the end of the morse taper shaft has 10 thou runout. With the chuck installed this is magnified the further from the chuck the drill bit is, the worse it gets.

The vendor has "no returns" on the ebay listing, so I may end up doomed. I think the chuck is good, so now I'll have to buy one of the Chinese SDA's. 

 <a href="https://www.youtube.com/watch?v=2xECLshgRQ4" target="_blank">http://www.youtube.com/watch?v=2xECLshgRQ4</a>

[steamer]

I'd take a shot at making a new shaft.   I suspect you can do better

Dave

[steamer]

Scored some German made  ( Gunter?) 0.1mm 1/8 shank drills.....

I might burn one to play  ( I have 6 in a ity bity plastic box)

Dave