Lathe tailstock drill attatchment

[RCDesign]

Made a tailstock modification today that I would like to share with you !

I have been using a home made drilling runner on my Boley/Leinen 8mm Reform lathe which I mainly use for making watchparts.

The runner was made from 8mm stainless steel rod which I turned down to the 7.5mm in the tailstock. A small 3-jaw China made chuck held the drill bits in place. I used the supplied adapter that came with the chuck - a Morse taper to straight 5mm hole. The chuck was not perfectly centered but I usually solved this by finding center with a graver and loosening the bolt on the tailstock for some extra play.

Last couple of weeks I made some parts that needed holes that where 0.4 and 0.2mm wide. The larger hole was no problem but when I drilled  a 0.2mm hole in brass and then in plexi - it was obvious that the setup had reached its limit!

So - what to do? First of all I needed better precision. So I removed  the adapter from the chuck and cut a matching Morse taper directly on my 7.5mm rod. Tests where very promising - I easily hit center with drillbits down to 0.3-0.2mm. Tests where then made with a 2 flute 100µm drill in brass and.......yes It worked! 

I wanted to have control of the depth as I need to make some parts with a 1mm  deep 100µm hole, this is hard with the lever operated versions that you usually see.

I first taught of making a downsized version of a "standard" tailstock  found on larger lathes but I had trouble making a good "custom" fit to the original Reform tailstock. 

Ended up with this first version:

The parts made:

Used M6 as it has a 1mm/turn pitch and a matching scale is easy to make. The taper on the outside of the tailstock took some experimenting to get right - but 3deg fits well!

The final result:'

'

Cut my "runner" a bit to much, so I only have 8mm travel - but it's enough for most work-will make a longer one if I need to!

Drilling a 100µm hole on a flat surface worked like a charm! 

So - that's my take on easy to make drill adaptors!

[Geo]

Excellent conversion, I do like quality innovation!

[StuartBaker104]

I need one of these!

Penny Farthing tools sells a ground shaft with a taper fit chuck that I bought a year or so ago for about £30, It works pretty well down to 0.5mm, but I crashed and burned recently trying to drill a 0.2 hole

I can’t quite see how this goes together. Have you welded the runner and winding bushes together?

Thinking about it, I have a cross slide and may be able to use that to control the feed - will have to play tomorrow.

Where do you get your drill bits?

[RCDesign]

I'll try to explain how it is made.

Edited October 28, 2018 by RCDesign
Hit post by mistake

[RCDesign]

Red: Inside taper that matches the original tailstock with stop screw - welded smaller part with a threaded M6 hole

Green: Drilled part that fits on runner (black) with stop screw-welded to small part that has a 4mm hole to seat the "leadscrew"

Orange/yellow: M6 "leadscrew"  turned down at the end to match 4mm hole in green part - welded to the knob (purple)

I made everything frron stainless so I could use my small TIG-welder, but it could be made (probably better) from brass so it would be easy to solder together instead!

Get most drills from Cousins (Dormer) but their smallest versions are very blunt - so I had to sharpen them under a microscope with i diamond hone. The 100µm ones I got from Amazon/Ebay? Sold as PCB-drills!

The setup works somewhat like i vice! 

Edited October 28, 2018 by RCDesign
Typo

[StuartBaker104]

Awesome inspiration. Cross slide re-purposed... 

Only 1/2 inch of travel before it hits the tailstock, but that should be plenty.

Wouldn’t have got here without you!

Thanks

 

 

[RCDesign]

19 hours ago, StuartBaker104 said:

Awesome inspiration. Cross slide re-purposed... 

Only 1/2 inch of travel before it hits the tailstock, but that should be plenty.

Wouldn’t have got here without you!

Thanks

 

 

Clever!

I was thinking somewhat in the same way at first but use my crosslide to part of the surface ´to be drilled!

You could make a simple attachment with a screw if you need more travel!