Hands

[RichardHarris123]

Hello all 

I need a second hand for a AS1220 according to budfun it's 0.22 mm. I can only find 0.21 mm. Will they fit  

[nickelsilver]

It's common to broach hands a bit to fit, especially small ones like this- usually easier to open a hole than close it. So that hand should be fine. Cousins has a wide selection of broaches in the right size range https://www.cousinsuk.com/category/broaches-cutting.

[LittleWatchShop]

9 minutes ago, RichardHarris123 said:

Hello all 

I need a second hand for a AS1220 according to budfun it's 0.22 mm. I can only find 0.21 mm. Will they fit  

Buy it and broach it. If you have never done that, buy two.

[RichardHarris123]

1 minute ago, LittleWatchShop said:

Buy it and broach it. If you have never done that, buy two.

I take it I will need a broach.

[LittleWatchShop]

3 hours ago, RichardHarris123 said:

I take it I will need a broach.

Yup. When I said "two" I meant two hands in case you get a little too aggressive. 

Edited April 14, 2022 by LittleWatchShop

[Shane]

On 4/14/2022 at 6:07 PM, LittleWatchShop said:

Yup. When I said "two" I meant two hands in case you get a little too aggressive. 

Too aggressive... I know there are dedicated tools for this but are you guys talking about using tapered broaches by hand?

The difference is .01 mm, .0004 in, 10 microns.

Potable water filters and automotive oil filters filter out 10 micron particles.  Gust thinking about a cutting tool should remove more than that in a softer material.

I have had some luck just burnishing small amounts from the back side with a tapered steel pin that I have.  I can't say what it was supposed to be or for what purpose it was made but I modified it to fit in my jeweling tool.  It has a fine semi satin finish and is held perpendicular to the table.  It is a bit slower than cutting but that gives back some extra control over turning a tapered broach by hand to an uncontrolled depth.  The jeweling tool gives fine adjustment of the finished depth and diameter achieved.  It should also produce a rounder hole than a tapered cutting broach.  Just protect the front surface from any damage, put some pressure against it and gently swivel the hand about the pin (if you can't swivel the hand you're pushing to hard).  I wouldn't try changing sizes by drastic amounts this way but for small discrepancies or the last little bit after cutting it's fine.  Just keep going until it fits.

Shane

[spectre6000]

What I've done in similar applications is get the broach that's the correct range, then find the spot that it's the right diameter with a micrometer. Mark it somehow; a tiny piece of masking tape for instance, or some graphite pencil lead. For larger format analogs (thinking a set of carburetor jet reams), I use paint pen marks that are semi-permanent, and do the full set in appropriate increments with alternating colors on whole numbers or fives/quarters. Then broach up to, or right before the mark, test fit, and go a up to/past the mark as needed.