
06-13-2007, 11:48 PM
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| | | Join Date: Mar 2007 Location: USA
Posts: 80
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Update on tramming the rigid ram Series 1 | | I did take the whole head off in order to change the motor shaft. It was pretty easy, actually. The head only weighs maybe a coupe hundred pounds. The manual says unhook all the wires, but I found there is enough service loop back in the column to pull the head out and lift it up about 6 inches (all that is required to change out the motor) without disconnecting anything.
There are four 1/2" socket head cap screws holding the head on. The lower right hand one has an eccentric bushing with a hex on it to allow some controlled adjustment. The thing that looks like some sort of key in the cross section is a large round disk bolted to the ram which fits into a matching pocket in the head. The fit isn't tight, but it is enough to locate and stabilize the head while you deal with the bolts. If you loosen the bolts even a few turns, the head stays put on the ram, but allows the head to rock back and forth so you can tram it sideways using the eccentric bushing. All pretty easy to do.
On mine, the previous owner (who was guilty of many Crimes Against Machinery) had added some 0.002 brass shim stock under the top two bolts in an attempt to correct the front-to-back tram (and then had set the left-to-right tram poorly). As a result, the head was off by about 0.002 over a 10" circle, low at the left rear. I removed the shims and re-trammed it. The table had sagged about 0.002 over the 10" circle, assuming it was perfect 20 years ago. Because the bolts are about 4.5 inches apart and the table is twice that far away, I added a couple of 0.001 stainless steel shims under the top two bolts, re-trammed it left to right, and tightened everything back up.
Now measures better than a tenth over the 10" circle.
Still have to complete the top end rebuild, most of the parts are the same as the J2 head, except the motor pulleys are mounted upside down. The burka in the picture is taped on to keep the dust and dirt out of the Z ballscrew area (the cover must be removed to access the head fixing bolts. If you look closely you can see the round locating disk behind the head. |