Machinists Corner

[arny]

Some Industrial PVC machining
https://www.youtube.com/watch?v=W1KqsSFgWgc

[XSRCdesign]

I know this thread hasn't had any activity in a while, but I figured its a good place to look.

I have a sherline lathe and mill. And have been using Jacobs chucks for smaller drill bits, but runout seems to be an issue. From what I'm reading a collet set is needed? Am I gathering that correctly?

[Duuuuuuuude]

Yup. Or a pin vice that will fit in a collet. I found one on ebay with a 1/4" shank on it. Runout is so-so, but it gets the job done and is way less obtrusive than a drill chuck.

[XSRCdesign]

So i guess I'll start looking then. Right now runout is bad enough I can see it.. I need to do something

[Duuuuuuuude]

Search "mill pin vice", you should get plenty of options. I think I paid $10 for mine...came with three different inserts for drill bits.

[JeepinDoug]

Check the run out on the spindle first.
I don't know if it's a common issue with a Sherline but when you add more tooling into the mix, you're adding more opurtunity for variables.
A good quality chuck is typically ground as a single unit with good tolerances.
When you add a collet to hold a different chuck, you start adding tolerances.
Make sure your spindle is clean and indicating well, then check to see if the chuck is bent. Also check the chuck jaws for chips or dents. Most good chucks have replaceable jaws.

[XSRCdesign]

Originally Posted by JeepinDoug

Check the run out on the spindle first.
I don't know if it's a common issue with a Sherline but when you add more tooling into the mix, you're adding more opurtunity for variables.
A good quality chuck is typically ground as a single unit with good tolerances.
When you add a collet to hold a different chuck, you start adding tolerances.
Make sure your spindle is clean and indicating well, then check to see if the chuck is bent. Also check the chuck jaws for chips or dents. Most good chucks have replaceable jaws.

They are both brand new machines.. Doesn't do it on my end mill or my live center. Only seems to be when I mount a chuck into the spindle on the mill or
The tail stock on the lathe. I have three different chucks and they all seem to do it. Maybe my setup is wrong?

[Duuuuuuuude]

How much runout are you getting?

[XSRCdesign]

Originally Posted by Duuuuuuuude

How much runout are you getting?

Well thats a good question.. guess id have to measure that?

enough that I thought my bits were bent and I got new ones..

[Duuuuuuuude]

Yeah, better measure. My chuck has about .002 runout, which doesn't really amount to much when you're using tiny bits because they'll flex and run fairly true once they've started cutting. But the very tips do look like they are bent when spinning.

[XSRCdesign]

Originally Posted by Duuuuuuuude

Yeah, better measure. My chuck has about .002 runout, which doesn't really amount to much when you're using tiny bits because they'll flex and run fairly true once they've started cutting. But the very tips do look like they are bent when spinning.

So I could be making my own issues.. Sounds about right hah

[Duuuuuuuude]

As long as it isn't throwing the hole too far out of spec there shouldn't be any worries. If I'm drilling soft materials (plastic) it'll start the hole a bit large, but once it settles in it's fine.

Sometimes you can also clock the tool runout to offset the collet or quill runout.

[XSRCdesign]

So I also learned you can chip a live center today... Ugh

[MonkeyFist]

Originally Posted by XSRCdesign

So I also learned you can chip a live center today... Ugh

If you try hard enough anything is possible.

[Hotrodblder]

If a person needed to switch thread count from metric to standard because that's the only hardware available, would you just try to go the next standard size up or try the standard "equivalent" so as to try and just recut the threads?

Sent from my AQT80 using Tapatalk

[Duuuuuuuude]

Unless it was something truly exotic, I would just get the proper hardware.

If you can't do that, drill large enough to remove the existing threads and retap.

Forcing the "standard equivalent" usually results in stripped out threads.

[Hotrodblder]

Originally Posted by Duuuuuuuude

Unless it was something truly exotic, I would just get the proper hardware.

If you can't do that, drill large enough to remove the existing threads and retap.

Forcing the "standard equivalent" usually results in stripped out threads.

Well, DUUUUUUUUde,
I ordered a set of wheels similar to locked ups wheel that uses the type of wheel stud as Locked Up. Locked Up uses 4/40 and these new wheels have M3 screws. For what I paid for the new wheels, I'm just wanting to make sure I can get replacement hardware if something happens since their so small.

Sent from my AQT80 using Tapatalk

[Duuuuuuuude]

So hunt down someone that sells hardware and buy extras. I can almost guarantee that whatever you need won't be that hard to find.

[XSRCdesign]

M3 hardware is pretty standard stuff

[BigSki]

Looking at my Starrett drill chart, the drill for a 4-40 tap hole is a #43 (.089) and the drill for a tap hole with M3 is a #40 (.098 ), so the 4-40 is already smaller than the metric hardware. You would need to get into a #6 machine screw size in order to re-tap the holes and get enough clean material to do it.

Like DUUUUUUUde and XSRC said, make life easier for yourself and just use the M3 hardware. It's a very easy to find size. You can even find a decent selection of it at any ACE Hardware store.