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Drilling a 0.0015"/40 µm diameter hole in a 0.005"/120 µm thick plastic

ksaisiva

Plastic
Joined
Jan 6, 2022
Hi I am using a Sherline 5400 Tabletop 12" Vertical Milling Machine to drill a 0.0015"/40 µm diameter hole in a plastic piece that is 0.005"/120 µm thick. The drill press has a three jaw self centering chuck. The runout on the chuck and the drill bit is between 0.0015" to 0.002". Is there a way to decrease this runout?

Thanks
 
The powers that be on the forum will not like the mention of a Sherline mill, so fair warning if the thread gets locked.

That being said, you will probably find it is nearly impossible to get less runnout than that with a Jacobs or similar type chuck. Best bet would probably be some sort of collet system, but you still may be limited by the concentricity of the spindle itself on that sort of machine. You could just try tapping the chuck lightly with a mallet and see if it changes the runnout.

Hope this helps.
 
Tapping the chuck to get it to center cannot hurt that machine and might be one of the nicer things to do to it.

Ed
 
You might put a larger drill of the same length as your to-size drill and spot the hole point and position , a center drill can be good for this.
Same length because the tram of your mill can offset a hole from the desired position.

Drill normale run close to the size if the point is well centered.

To make a more exact drill size one pre drills the hold with a smaller drill, then drill with the to-size drill.

For a hole in a plastic piece, all bets are off because plastic can melt and is not solid enough to hold a drill from windering.

A .0015 drill will be very tricky to not break it with overfeeding, I'm not experienced in such small drills.
 
For .005 plastic stock, I wonder if you might grind a drill flat bottom. set up a guide bushing over and a die under and then punch the holes.

This would be a good test if you break a drill or two...use/try one as a punch
 
Punching sounds like a good idea to try. I think [brand that can't be mentioned] makes a good hobby/jeweler's lathe, but IMO their mill is a flimsy thing. A proper setup for tiny holes runs the drill directly in V-blocks with a small belt, no chuck at all, so just the inherent runout of the drill bit itself. It's rare to see this and I don't know if anything is commercially available.
 
3xd is way to deep for a punch. Agree collet or tool holder would be better than a chuck. The mill is plenty stout for a .00 anything bit/cutter. The drill should self straighten as it goes through. It is a 3xd hole, just a small d. Might freeze the plastic first to give a little support to the drill.
 
I's sorry, you're calling this stout?

12″ Deluxe Vertical Milling Machine – Sherline Products

I know a tool of that size exerts almost zero force, but I would expect the motor vibrations to cause it to move a thou or two on it's aluminum dovetail gibbs.

there is a reason they are used in jewelry and chronograph world. Not stout, but very well built with minimal vibration. A 1/8" is a rougher/facing mill at this scale.
 
I have a [unmentionable] mill at work. There are many words I could use to describe it but "stout" would be last on the list. At the scale we're talking about you need a total lack of vibration and, though the job may be doable, that column acts too much like a spring. I will give the thing credit for having a very low vibration motor and belt drive.
 








 
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