Mill Tramming Query

I have read that a milling machine should be trammed before each project and even before starting work each day.

What I do not understand is why this becomes necessary. Assuming only the one person ever uses a milling machine, and that it is not abused, why once the mill has been trammed to an acceptable degree of trueness should it go out of true?

If a mill is of robust and solid construction what moves to send it out? I am thinking heavy vertical round column mill here, with solid base securely fastened down with four strong bolts.

Would be grateful for illumination on this please.

ChrisH

Well it would be good practice to check alignment daily but you would never have time to make anything.

I think I would call tramming a mill 'work' so be hard to do before you start work!

Seriously, I think what you read fall into the same category as, (for example)

Checking Tyre pressures and engine oil level, screenwasher fluid before 'every' car journey!

Ian P

Hi CrisH

In industry we never trammed for the sake of it.

Normally you would notice if a mill was not cutting square.

Tramming was usually down after roughing down a job with a tipped cutter where you were taking heavy cuts and when you had tilted the head.

Tramming does not take very long anyway, 10 minutes at most.

regards David

A lot will depend on if you have a fixed head or one that can tilt side to side. I trammed my X3 when I got it by shimming the column to the base and have not touched it again in 5years.

A tilt head mill even a bridgeport can go out of tram a lot quicker, take too heavy a cut or have some sort of snatch or jam up particularly on the smaller machines and things can move. On a machine like this its best to check before you do any majorly critical parts at least that way you get some work done rather than spending all day tweaking the last 0.00001"

J

Doesn't the fact that heavy cuts or a snatch can disturb the settings of a milling machine indicate poor machine design or construction?

My Emco mill has a tilting head, no matter how tight I clamp the bolts I know it will move if I take heavy cuts, I'm referring to cuts that are well within the capability limit of every other part of the machine.

I am sure that at the design stage the head clamping arrangement could have been done better. As it is I have to be very careful using the machine as tramming (the head) can take an hour (Its a trial and error process as there is no fine adjustment other than changing the size of hammer!)

Ian P

It would be too late if you noticed it after you had ruined a job that had had a lot of time invested in it!

Ian P

My old Dore Westbury has a round column. Tramming on the X axis is easy. because the head can be tilted, but tramming on Y involves shims.

If precision is essential, I check the tram. I'm not sure if the column is dead straight, so while it might be perfectly trammed at one height, that might not be true when the height is changed.

If shimming is needed, there's a nice way of finding what thickness is need on page 6 of this PDF.

Andy

A quick way of "checking" the alignment is to take a cut on a flat metal sample with a known sharp cutter and observe on the second clear pass how the cut is, leading edge only, trailing edge as well or heaven forbid, trailing edge only. Both axes. If clean cutting OK, if not, you have some idea as to the extent of "out of tram". Bear in mind that an out of tram head cuts a curved hollow along the direction of movement. Similarly if you cut a parallel 2nd pass then you can feel/see the "step" if you are out of tram.

Hi Bog Standard2

How about an article for MEW?

regards David

Hi DC1,

Remember the fun and games the last time Bog's words were in your magazine? His words and deeds but someone else's name appeared as the author, with the true author's permission, which upset a few people who knew who had written it.

christephens

EDIT. I do hope you can persuade John to write for you, his words of true wisdom are sadly missing laterly.

Edited By chris stephens on 17/10/2012 12:53:17

Hi Guys
At work we only checked alignment /tramming if we had tilted the head for putiing angle dowels etc.
Nobby

Hi Bogstandard2

I thought it deserved to be more widely shown. Not all Model Engineers' Workshop readers have access to the internet.

You copuld always donate fees to REMAP.

regards David

Hi There

Was that the marcher engine rebuild?

I had no idea it was written by someone else.

regards David

I am sorry about this John

He said he had permission.

Not sure what I can do about it now.

regards David

Emails as received.

Regards David

David,
Thanks for your e-mail I have transfered all pics to CD with a Word doc which you can edit as you please .in the post to you Tues.

Extra notes

the engine size is 7/16 twin by 7/16 bore and stroke.

The engineeer who did the refurb is John ******, John is not in the best of health at the present, and his wife is very ill.

Regards Roy

Hi Roy
Who should I be paying?
regards David


Hi David.,

Its OK to send payment to me, its been agreed,

Regards,

Roy

Hi John, (Bogstandard2),

My mill/drill is the Warco 'Economy', just about the same as the Axminster ZX25, the Chester Eagle 25, and a few others I guess besides. My view was that it could only be trammed by shimming between base and column and that should last for ages, but, I am indebted to you for attaching the link to your dual gauge tramming tool. What a well written thread! As it happens, I have a couple of gauges going spare, looks like another project to put on the "must do" list!

Cheers,

Chris