Tiny Drill chuck

[Susquatch]

My "Indian" Micro Drill arrived yesterday. $60 plus 20 for UPS shipping & no tax. 80 all in to the door. (NB - Amazon has raised the price to 67)

Micro Drill Adapter Miniature Quill 1/2" Shank with JT0 Drill Chuck 0.3-4 mm-Manual Feed Control Avoids Drill Breakage Milling Tools (With Chuck) : Amazon.ca: Industrial & Scientific

Micro Drill Adapter Miniature Quill 1/2" Shank with JT0 Drill Chuck 0.3-4 mm-Manual Feed Control Avoids Drill Breakage Milling Tools (With Chuck) : Amazon.ca: Industrial & Scientific

www.amazon.ca

It came with the JT0 chuck and key. I'm not disappointed. It's a clean little chuck that closes much smaller than 0.3mm. No idea how small, but prolly under 0.1

There is a certain rough feel to the drive slip fit but that is probably the internal spring rubbing when it is extended and retracted.

The shaft fits my 1/2" R8 collet perfectly.

As I hoped, the unit will work on my mill, my drill press, my mill/drill, and on my lathe. I spun it up on my Hartford Mill and it is as smooth as glass and doesn't wobble visibly at all. It drilled a perfect little hole in the mild steel plate I tried it on.

It may not have the quality of an Albrecht but it will be just fine for my needs.

Great value. No regrets.

 

[Mcgyver]

if you get a chance, chuck and pin and see what the runout is.

 

[Susquatch]

if you get a chance, chuck and pin and see what the runout is.

It was in the plan.

Might have to wait a while for me to do it though. My thinking is to do it right if I'm gunna do it. So I'll need to get a baseline on the 1/2" collet first or make a custom holder for the lathe.

If you have thoughts on how best to do that, I'm open to suggestions.

 

[Mcgyver]

that sounds right. All I've ever done is like you suggest, indicate each stage so you can get a sense of where the run out is

 

[gerritv]

While perusing back issues of Horological Journal, I came across an article on drilling small holes (as in 0.1mm to 1mm). To quote the summary:
"The essence of success with drilling small holes is to use a sharp drill with a light touch and a slow speed. Though not mentioned in standard instruction books, I find that using R.T.D. oil helps cutting a very great deal and would not drill steel without it. The two main difficulties met are the formation of the devil in the hole which may become hardened by un-intentional burnishing and the burnishing formed at the end of the hole by a blunt drill or too great a speed."
Many of the watchmaking drills in that size are not twist drills, rather they are arrow head. Which are quite easy to make yourself. One benefit is that they don't corkscrew themselves into brass, and snapping off.

Gerrit

 

[PeterT]

A somewhat more independent way to measure your drill chuck runout is position the shank in V block(s). It kind of needs 2.5 hands but its not difficult. Jaw grip the most accurate dowel pin you have in your inventory. Measure radial runout at different positions down the pin with a tenths indicator by rotating the shank pressed lightly in the Vee crotch. You can also measure down the length of the pin which is related & might help explain readings depending what they are. Repeat with different size pin. Repeat with a slightly different grip. This collectively is assuming the shank is the datum surface & you are getting a sense of how the chuck body/jaws are behaving relative to that. Introducing the chuck assembly into the mill is more convenient to measure TIR but now you have baked in a few other variables which may stack better or worse depending on the combination (collet inner & outer surface, mill seat surface, mill bearings...)