tramming mill drill

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umahunter

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Well I have purchased a brake rotar and am going to attempt to get my jet jmd 18 square .what I'm wondering is which indicator I should choose I have a .001 and a interapid .0005 I planned to use the .0005 but am wondering if this level of accuracy is attainable on the mill drill ???

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It may not be attainable, but it should make it easier getting as close as you can. Mike
 
If you are going to use the setup in your pic, position the indicator needle about 11 degrees (or less) off the horizontal so it will read correctly.

I just use a piece of bent rod and whatever ground block that's the right height to clear what's on the table. The longer the swing the more accurate the tram:

milltram003.jpg

milltram001.jpg

milltram003.jpg

milltram001.jpg

milltram003.jpg

milltram001.jpg
 
A NEW Brake Rotor may not be a good surface to reference off.

When I was working as a mechanic we ALWAYS resurfaced ALL New Rotors BEFORE installing them and when taking a touch cut for Zero reference they were almost always off.

You may want to have that surfaced before you use it and have them take a dial indicator to it and provide the actual run-out. There is a very good chance you will be surprised at the run-out.

ALL Brake Rotors MUST have run-out to function properly.

The run-out is what gently pushes the piston back to provide operational clearance for running. Without that the brake pads would be in constant contact with the rotor surface and drag creating problems.​
 
ALL Brake Rotors MUST have run-out to function properly.

When I worked at Kelsey Hayes, making brake rotors if they ran out .003 they went to rework.
 
Holescreek said:
If you are going to use the setup in your pic, position the indicator needle about 11 degrees (or less) off the horizontal so it will read correctly.

I just use a piece of bent rod and whatever ground block that's the right height to clear what's on the table. The longer the swing the more accurate the tram:
Click to expand...

Thanks Holescreek! Never thought of moving a block around like that... Great option for mid-setup tramming


Bernie
 
yendor said:
A NEW Brake Rotor may not be a good surface to reference off.

When I was working as a mechanic we ALWAYS resurfaced ALL New Rotors BEFORE installing them and when taking a touch cut for Zero reference they were almost always off.

You may want to have that surfaced before you use it and have them take a dial indicator to it and provide the actual run-out. There is a very good chance you will be surprised at the run-out.

ALL Brake Rotors MUST have run-out to function properly.

The run-out is what gently pushes the piston back to provide operational clearance for running. Without that the brake pads would be in constant contact with the rotor surface and drag creating problems.​
Click to expand...

Yendor-
I had no idea about that mechanism for pushing the rotor back, wow, no kidding.

Makes sense, as long as the runout occurs more than once per rev, otherwise you would feel it, right?

Bernie
 
T Bredthoft would be correct that more then .003 of run-out would be cause to resurface a rotor but .003 is way more than you want when trying to tram a mill.

If you start with .003 of run-out how would you ever get it correct. If you got it to tram out to Zero you will have most likely built in an error that is unacceptable.
 
I agree, don't use a rotor, unless you know it's very true. Most people tram directly off the table, If you are going to tram off something other than the table, use something like a well matched pair of 1-2-3 blocks.

use the 0.0005" indicator, as you want to tram as accurately as you can. You should be able to adjust any mill to perfect. What machine does under working conditions is a different story.
 
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