Milling Rite

[Larry$]

I need to adjust the contact on the indicator to better index the inside surface of the fixed jaw, but I'm not sure exactly how to do that,

The contact arm can just be pushed back with you fingers.

 

[Dave Bonzo]

The contact arm can just be pushed back with you fingers.

That's what I thought, but when I gave it a gentle shove it didn't move. So, I did a quick loosen/tighten on the screws like I was going to change the contact, and shoved a bit harder; amazingly, now the contact moves. Maybe it was just a bit stiff or I was being too careful; either way, thanks.

Also, you know what would probably help? Locking the Y axis when I do this, is what. I bet that's at least a few ten-thousandths of movement, and I can't imagine that the movable jaw of the vise is any less.

 

[Larry$]

Also, you know what would probably help? Locking the Y axis when I do this, is what.

Maybe, but I doubt it. Easy to find out, do some tests.
You will find that the needle bobbles as it slides along the jaw face even though the face feels smooth. Ignore it.
No idea if I tram correctly or not... But, I'll get the vice snugged pretty tight on one side. Locate the indicator arm close to the opposite side, start the X feed running slow. Use a mallet to tap the vice as the indicator traces across the jaw. By the time it reaches the opposite side you will be very close. One more pass to tweak the last bit out. Always take your readings with the indicator moving in the same direction. Doesn't matter which. The friction on the tip will affect readings. When you are ready for the final check do it by moving the Y axis in & out to avoid any errors from the twisting action on the indicator. Is it worth the time to do that?? If you think you can maintain 10ths Maybe. There are an awful lot of points of potential movement on an inexpensive setup that may negativize the usefulness of a lot of tail chasing.
Best thing is to design for tolerances. There is no such thing as "perfect!"

 

[Dave Bonzo]

Maybe, but I doubt it. Easy to find out, do some tests.

It helped. I think I need to tighten that gib just a bit.

You will find that the needle bobbles as it slides along the jaw face even though the face feels smooth. Ignore it.

It really didn't move much; barely trembled a bit, but that's all. I wasn't too worried about it.

No idea if I tram correctly or not... But, I'll get the vice snugged pretty tight on one side. Locate the indicator arm close to the opposite side, start the X feed running slow. Use a mallet to tap the vice as the indicator traces across the jaw. By the time it reaches the opposite side you will be very close. One more pass to tweak the last bit out.

That's very close to what I did, but I was reading from the snugged side and working towards the other, correcting a bit as I went; basically, I moved away from the pivot point.

Always take your readings with the indicator moving in the same direction. Doesn't matter which. The friction on the tip will affect readings. When you are ready for the final check do it by moving the Y axis in & out to avoid any errors from the twisting action on the indicator.

Didn't think of that. I checked in both directions because I kept getting erroneous readings one way or another.

Is it worth the time to do that?? If you think you can maintain 10ths Maybe.

Tenths of an inch? Yes, I can do that. Anything else is asking a lot of me, right now.

There are an awful lot of points of potential movement on an inexpensive setup that may negativize the usefulness of a lot of tail chasing.

You are incredibly right about that; things just kind of wobble a bit, here and there. That's making it difficult.

Best thing is to design for tolerances. There is no such thing as "perfect!"

That is the absolute truth, right there. Right now I'm trying to learn how to do this as much as I'm trying to get it as close as I can, and hopefully that'll allow me to do the best job possible...and for my "best" to improve over time.

 

[Larry$]

Tenths of an inch?

0.0001" = tenths! A tenth of a thousandth!

 

[Dave Bonzo]

0.0001" = tenths! A tenth of a thousandth!

I know; I was just messing with you. Couldn't insert the winking emoji.

But for seriously: I can do tenths of an inch.

 

[Larry$]

But for seriously: I can do tenths of an inch.

Me too, It just might not be the tenths I wanted.
There are some fits that need tenths but not many. Press fits. I've under shot them often enough that I now use a file for the last bit.