A quick alternative to mill tramming

[Crusty]

Do you find yourself using less than optimum approaches to remove metal because you don't want to tram your mill in again afterwards? I know I did until I adopted this procedure that Keith Rucker uses instead of tramming his mill. He uses a cylindrical square directly against the quill of his mill to set it exactly square to the table (the objective of tramming) but those are really expensive.

I used a precision shaft chucked in the spindle (I think highly of Thompson QS precision shafting) and one of a pair of 2-4-6 blocks that I bought for this purpose (as well as other setup uses) and my mill was trammed better in 5 minutes than I had previously done with an indicator on a bar in the spindle. The 2-4-6 block is eased against the chucked shaft with a bright flashlight directed from behind and you can easily see .001" out of square like this, and this method when completed is close enough to perfectly square that a surfacing cutter leaves cross marks in the milled surface. Use a portion of the block where the surface is continuous and not interrupted by the holes in the block.

All in I think I've got less than $100 in this method as well as some more useful items for setup.

[Crusty]

Coincidentally, Keith posted a video where he performed his tram procedure and then tested it with a new tramming tool he was evaluating and his manual method was off by 3 ten-thousandths over 6 inches in the nod axis and 3½ thousandths over 6 inches in the X axis, and I think he could have gone through his procedure without a camera recording and done better. Either way is close enough for me because I always design for wide tolerances.

[metric_taper]

This seems like a faster way then spinning an indicator around and having to jump over the slots. I think I can use a piece of drill rod, that has always seemed very straight.
Thanks Crusty

[Crusty]

Drill rod should work fine and I recommend a 2-4-6 block to judge against because then you'll have a full 6" of reference surface when it's stood upright which will give you better resolution. They're precision ground and heavy which helps too. Judge your drill rod against the block on the bench before you start and that'll tell you whether it's straight enough to use. I used 1/2" precision shafting and that size seemed rigid enough.

Seriously, it took me all of 5 minutes to adjust my mill better than I've ever been able to do tramming with an indicator in several hours.

[JoeH]

Always glad to learn new ways. This sounds very interesting. I didn't know 2-4-6 blocks existed. Thanks.

[Crusty]

Yup and they're useful for supporting odd things too. I found affordable ones on Amazon, as well as a pair of 1-2-3 blocks that I already had.

[DIYer]

Thanks Crusty! We've added your Mill Tramming Method to our Measuring and Marking category,
as well as to your builder page: Crusty's Homemade Tools. Your receipt:

Mill Tramming Method by Crusty

tags: mill, measurement, tramming

[stillldoinit]

Back in my machine repair days before retiring I quite often had to align spindle in CNC machining centers and also precision vertical double disc grinders. I had a 1" plate 12" diameter of 4140 hardened and ground parallel to 2 tenth tolerance. I used that for tramming everything after slot beds were stoned and all burrs removed. That eliminated slot jump. The bridgeport I have at home is really beat but does metal butchering just fine for what I do now. It was a parts machine to keep others running if a part replacement was needed quicker than ordering. Everytime I took something off, I would make sure the old part went with it. After we moved, I brought it with and cleaned it up and put back together. The 3 phase motor was locked up from sitting in unheated building for 20 years. It now has a 2.75hp treadmill motor with harbor freight speed control going through full wave bridge rectifier. Rarely have to change belt position. It is basically a very solid drill press and metal carving hog. So like someone's idea here, it isn't precision but is very adjustable.

[rjitreeman0909]

Good method Crusty. If you get it to better than .001 over 6 inches, that is better than .015 degrees. Depending on the fine adjustment capability of any given head it should be possible to get it even better. Added suggestion. To eliminate any run out error of the spindle/collet system, rotate the spindle 1/2 turn and confirm. Any difference is an indication of a spindle system not running true. Remove cooler, clean spindle bore, ID and OD of collet and the bar stock, reassemble and recheck. Thanks. Bob the Treeman

[Wildwilly]

Nice to learn something to save time.....on the night before Christmas! Merry Christmas y'all!