Unimat DB200 Milling Question

[mvagusta]

I am a new Unimat user and need to mill a small part. I would appreciate tips on how to accurately measure changes in the tool height when a precision depth is required. It is easy enough to move the carriage and cross feed in precision increments using the markings on the handwheels but there is no equivalent for the vertical axis when set up for milling. Any hints would be appreciated. Thanks.

 

[markba633csi]

Very true there is no vernier adjustment for vertical axis, only the pinion lever and rack on the headstock quill. You could perhaps
make up some type of screw feed for this- It's a very simple machine as designed

 

[Ulma Doctor]

I use a DTI and indicate the spindle protrusion for tool height

 

[markba633csi]

The milling column is not very secure on these- ok for soft metals but not rigid enough for steel; the headstock moves with hi cutting forces

 

[mvagusta]

Very true there is no vernier adjustment for vertical axis, only the pinion lever and rack on the headstock quill. You could perhaps
make up some type of screw feed for this- It's a very simple machine as designed

Yeah, I figured that out when I made a plan for machining a dial clamp for my Mitutoyo dial calipers (I broke the original) and realized I had no feedback on the quill position.

I use a DTI and indicate the spindle protrusion for tool height

Do you have any photos? There don't appear to be any convenient places from which to take a measurement. I assume by DTI you mean something like this:



I did find a mention of a clever setup for measuring the quill travel in the Unimat section of Groups.io. The YouTube video showing it is here.

It just occurred to me that I might be able to set a telescoping hole gauge to a specific height to measure this distance:



I could then set it to a different height when I wanted to go deeper or shallower. The part is quite small and I would not need to acquire a new gauge or gauge mount in order to make the part now.

 

[Ulma Doctor]

I use this type of DTI

 

[mvagusta]

I use a DTI and indicate the spindle protrusion for tool height

Thanks for the photo of the test indicator. I am a little confused, though. The one in the photo looks like it has a total range of travel of +/-0.015" = 0.030" but the range of travel on the quill is more like 16 or 17 mm, which is around 0.66". I have never seen a test indicator with that kind of range. I can't figure out how one could be used to measure the quill position. How do you do it?