Thread: Tramming round column MD30
Haven't set my mill up yet as not built the stand for it... but once I do I am thinking I may need to tram the column/head. Just wondering how other round column owners (Robin, Keith, etc.) have done this.. or not as the case may be....
In a word - patience (lots of it........).
My Dore Westbury is a complete pig to get truly square, as not only does it have a round column, but it also has a round head support, one that allows the head to pivot sideways.
Aligning X and Y is pretty straightforward, as the head "swing" position doesn't do anything other than alter the effective cutting area on the table, it's getting the head square to the table that takes a fair bit of patience. I don't know what the correct way to adjust it is, but I use the biggest fly cutter I have and just tweak the head (with the lock screw partially tightened, I just whack the head with a soft mallet to jog it around a bit - crude, but effective). I take consecutive cuts on bit of scrap with the fly cutter until I get it "just" cutting on both sides equally.
I've tried setting it up square to the table with a precision square, but the quill isn't long enough to get decent resolution. The big flycutter seems to be far more sensitive to small misalignment.
As an aside, when tramming up the milling vice I now use an old broken long end mill with the cutting part ground off as an edge finder. I clamp a straight edge in the vice securing it to the table with just one of the two tee nuts fairly tight and the other fairly loose. I lower the Z axis until the edge finder is just touching the end of the straightedge where the vice tee nut is clamped fairly tightly. With the straightedge obviously skewed further towards the edge finder I then gently traverse the table. This twists the vice around square, whereupon the remaining bolt can be tightened. I find that I can usually set the vice square to within a thou after no more than a couple of goes at this. There may well be a "proper" way to do this, I'm entirely self taught!
There is a right way... see this video http://techtv.mit.edu/genres/24-how-...machine-shop-4
but the MD30 doesnt have, AFAIK, any way to rotate the head in the z/y plane, only in the X/Y plane
I read somewhere (can't find it now) about shimming the column support, but I'm not so keen on that...
Thanks for that, how I wish everything was that smooth on my mill!
It was nice to know that the "proper" way involves whacking things with a mallet. I forgot to add that I also use a DTI to check things, but instead of sticking it in a chuck/collet, I simply plonk the magnetic base on the side of the head. My vice doesn't rotate around a centre bearing, so I end up swinging it around one of the mounting bolts, which tends to make it a bit more fiddly to get right.
I will try that head-straightening techinique next time I feel mad enough to change it from it's present setting. Although I'm sure having the ability to rotate the head around can be useful, it does tend to make for one more thing to go out of true when you least expect it.
Sorry I can't help with your problem, my guess is similar to yours, in that you probably need to shim things to square them up.
well once I have made a stand and mounted the mill I'll see how bad it is and take a view then...
For what it's worth...
For my NuTool MD500-30 (RF30 clone) I levelled the stand, then shimmed the base until the table was level.
I trammed the head, with a dial gauge mounted on a long bar (horizontally) mounted in the chuck so it could spin around several inches to the left, right, back and front of the table. I used a smooth parallel block between the rough-ish table surface and the dial to get a consistant zero.
I shimmed the base of the column with the thinest shim stock, until the it dialled zero (+/- 0.001-2) all around (the column flexes more than this if pushed :()
BTW I stripped the machine and rebuilt it, from the floor up. The columns are shimmed from new!
Well my collets and drawbar have arrived and I would have been playing this weekend if the builders working in the kitchen hadn't fractured a gas pipe. So had no heating this weekend and stayed at my son's instead. On the bright side, got to watch most of the 6 Nations matches!
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