Hello, I have recently obtained a bench type column/dovetail mill. While checking out tram/alignment etc, I was surprised to find out how 'springy' the column is. With an indicator in the spindle that is touching the table (measuring in Z direction), With one finger worth of push on the very top of the column (not pushing on the head) I can get the indicator to move .001". Is this normal for these machines ? Its a larger machine, 833, about 750 Lbs .
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Bench type mill rigidity
- Thread starter gjestico
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I would think that the column is not the problem. I feel it might be at where the column is mounted to the flange that holds it to the base. .001 whiteout a load makes you wonder how much under a load, but then again what's your actual intentions for the mill.
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You want to replace the bolts at the base of the column with stronger ones- grade 8 at least, and make sure the surfaces are clean and flat
A slight bit of flex is unavoidable with a machine like this just by design, but you should be able to reduce it- there may be burrs/debris that are
holding the surfaces apart
A slight bit of flex is unavoidable with a machine like this just by design, but you should be able to reduce it- there may be burrs/debris that are
holding the surfaces apart
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Welcome H-M.
Was the Z-axis locked, when you took your measurement?
On my bench mill, I've found two things that can effect my Z axis height readings...
1) If my Z axis gibb is adjusted too loosely.
2) My Z axis is not locked.
Was the Z-axis locked, when you took your measurement?
On my bench mill, I've found two things that can effect my Z axis height readings...
1) If my Z axis gibb is adjusted too loosely.
2) My Z axis is not locked.
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- Apr 8, 2013
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I just replaced my lead screw drive head lift on the top of my RF30 KO mill with a worm drive on the side of the mill. This clears the top of my column and I plan to put about 60 lbs of weight up there to dampen vibrations. I just finished the worm drive yesterday (member's projects) so I haven't put the weight on the column yet. I'll post when I get it done.
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Post what you've done. Sounds good.
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What brand and model benchtop mill do you have?
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The gearbox is already posted in members projects and I'll post the results of the column weight in the next few days. I'm awaiting shoulder replacement surgery so I can't put the weight up there myself. I'll probably start with an 8x8x16 cement block.
Its a PM-833 . This is my first 'hobby' mill and is the biggest one i could get in to my tiny workshop. My professional experience is with full size knee mills, But no way could I have got one of those in the room.
I just wonder if thats how it is with these types of mills. I can imagine lots of z movement with actual cutting forces in play (especially drilling)
Hi, I’m on par with changing the bolts to grade 8 and making sure those mating surfaces are clean and flat as suggested above. I had to do just that to mine to get my tram correct