Project: Dial Indicator Holder

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Tuesday, Oct 31 2017

When I need to measure lathe Z axis travel I’ve been using a dial indicator on a magnet. Keeping the magnet free of chips is a pain. I used a holder with a cam mechanism that locked it to the ways on my previous lathe. It’s time to build something similar for my current lathe.

I didn’t take any pictures of the build. The steps were

2" Dial indicater on holder

2" Dial indicater on holder

2" Dial indicater on holder

1 square up some aluminum stock
2 cut a slot in the stock the width and depth of the rear lathe way
3 turn a cam out of some brass
4 drill a hole for the cam
5 drill and tap a hole to hold the meter
6 make a handle out of some aluminum plate
7 assemble

Rear side of holder

Rear side of holder

Rear side of holder
Close up of cam mechanism

Close up of cam mechanism

Close up of cam mechanism

The cam was made by offsetting some 8 mm brass rod about 2 mm in 4-jaw chuck then turning the rod down to a 6 mm diameter. The 6 mm section is the axis of the cam with the offset 8 mm section providing the cam action.

I also ordered a dial indicator with 2" of travel. When the tail stock gets in the way I can mount a 1" indicator on the holder instead of the 2" indicator pictured. For most of the work I do the 2" will work fine.

When cleaning up part of the brass cam mechanism I mounted my collet chuck on the lathe. I noticed a bad out-of-balance condition when running at higher RPM. No wonder. The chuck was made from a heavy backing plate that was drilled to mount with either a 3 or 4 screws. That meant two extra holes on one half of the disk.

Balanced chuck

Balanced chuck

Balanced chuck
No more heavy spot

No more heavy spot

No more heavy spot

I mounted a rod through the chuck and gave it a rough balance check. Yup, the half of the disk with the extra holes was the light side. I drilled two new holes to offset the extra holes on the light side. I guestimated the location. Since I wasn’t going to counter sink the new holes I wasn’t going to remove as much material, so I moved the holes closer to the heaviest spot of the assembly.

My guestimate was fine. The chuck no longer had any noticable heavy spot when tested on my improvised balance stand. It is balanced enough to run at the highest lathe speed without causing vibrations, something I could not do before.

Wednesday, Nov 15 2017

Well, that wasn’t very smart. The indicator arm was blocking access to the carriage lock cap screw. I could use the indicator or lock the carriage, but not both at the same time.

I added a spacer to move the indicator about 20 mm closer to the operator. That gives me access to the carriage lock with a hex wrench as shown when the indicator is being used. The second picture shows that the spacer just clears the flat part of the way nearest the operator.

 

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