Mill Traming

richz

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Question on mill traming. Awhile ago I was reading about someone who used treaded rods to tram their mill. There was talk about a loss of rigidity and someone else also stated that if it was done this way it should be grouted. When I tramed my PM932 I have one side shimmed with 0.020 thousands. Technically the two surfaces would not be touching. Should this be grouted?
 
I have a Bridgeport. And no grout. And no treaded rods.
There must be something about tramming this PM932 mill that’s way different?
 
You don’t need grout or shims to tram the PM-932 mill side to side. You adjust the head tilt toget the side to side tram, and a long pieces of shim stock to adjust nod front to back tilt. I have my 932m PDF so close it cuts mirror facing cuts no ridges. It stays in tram too.
Good luck.
CH
 
I had an RF45 clone a while back and shims under the column did not effect rigidity. I had the column shimmed for tilt and nod.

I also replaced the 4.6 column bolts with 12.9 and added additional torque to the bolts.

You need to tram the column in both X and Y. If you only tram nod and the column is leaning (as mine was) it will effect X axis positional accuracy when you move the head up and down. You can check this by boring a hole with the head down as far as possible, raise the head as high as it will go and use a centre finder to check if it is still centred in the hole.
 
warrjon do you think replacing the column mounting bolts with threaded studs and using nuts under the column would affect rigidity?
 
Yes using threaded rod will effect rigidity, it has to. Although to what extent I do not know. A bolt (or rod) will stretch. When the bolt is torqued down correctly the stretch is reduced. This is why I used shims, I used 12.9 bolts and torqued them to spec. Shimming takes longer but IMO is the better way to go.
 
The Threaded Rod option works pretty well for the Mini Mill type units.
But on those units we typically tke light cuts and the work effort isn't as demanding.
 
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