Tramming my mill nod

[pgk pgkParticipant @pgkpgk17461]

I'm feeling dense today so need to check this, please.

This isa chester superlux. I was trying totrma it in last night.. got the sideaxis within 0.01mm o my DTI with a spread of 24cm (ie 12cm horizontal arm).. whch is probably more than within the resolution of a cheap DTI. (and not easy with the way tightening the bolts affects stuff)

The nod measures some 0.07 to 0.08mm on the same spread. The only adjustment wouldbe by shimming column bolts.

If my brain isnt malfunctioning too much then i see that as a ned to shim the back bolt to tilt forards by half that measured nod? And with the fore-aft bolt spacing being approx 12cm that would theoretically be 0.02 shim??? Which would be less than a thou shim in old fashioned money i.e best left alone???

Or are my sums right out?

[pgk pgkParticipant @pgkpgk17461]

[Colin HeseltineParticipant @colinheseltine48622]

I also have a superlux.had same issue. I loosened up the four holding bolts and pushed the column backwards. Then used a pair of feeler gauges. Shimmed up an appropriate amount then retightened bolts. Repeated as necessary till happy then replaced feeler gauges with plastishim to the required thickness. Fully tightened an rechecked. When fully tight was still out a fraction so amended shim pack slightly. One correct should not have to touch ever again.

Hope it goes ok.

Colin

[VicParticipant @vic]

Might be worth looking to see if any paint has crept in where it shouldn't be, It's happened before. Of course, if you scrape out any errant paint it could make it worse the other way! Let's hear how you get on.

[pgk pgkParticipant @pgkpgk17461]

By heck there were some typos there (sticky laptop keyboard in the shed!)

I was thinking dual feeler guages if I was going to do it, too… and once corrected cut them off and run a bead of silicone sealant around the junction? It was more a case of a math starting point.

The other minor issues with this mill…the nylon fan in the main motor head has a cracked boss and sits skewed and rubs and whoever tghtened up the fixings on the guard cracked both plastic mount holes so replacements requested. The manual supplied is dire so use the one from Grizzly's site to see how to access the spindles for cleaning and greasing. It was also supplied with a freebie surfacing mill that uses 4 bits of 12×12 HSS but the bits in there have some really nasty casting inclusions so I'll chop up/grind some nice bits from one of my 5%Cro's. And the usual crappy chinese gearbox so you have to twist-rock the quill to help change gear. I hope that will loosen up a bit when it's run in.

[Douglas JohnstonParticipant @douglasjohnston98463]

Posted by pgk pgk on 20/01/2015 06:45:01:

By heck there were some typos there (sticky laptop keyboard in the shed!)

What have you been getting up to in the shed with that laptop?

Doug

[Colin HeseltineParticipant @colinheseltine48622]

If you can locate it I would suggest the plastishim would be better than the feeler gauge as you could cut a length to go across the whole front of the pillar, which is what I did.

Colin

[Bob Brown 1Participant @bobbrown1]

plastishim????? why would you use plastic on a machine tool surely you'd use steel shims. After all the there is the issue of rigidity.

Bob

[pgk pgkParticipant @pgkpgk17461]

Just to remind folk that the original question was regarding the math for shimming..since I was feeling particulalrly dense at the time.

That is a bit moot right now. I've just been rechecking and the sideways tram was out again. One of the problems with this model is that it shifts as you tighten the head bolts and I'd obviously not doged them donw enough last time anyway. After much pratting about Ive got it to 0.03mm over a DTI width of about 18cm. Not as perfect as I;d have liked but the head bolts are dogged as tight as my 18stone can lean on them.

Right now the nod has gone.. so evidently the head bolt tightness affects the way the head sits against the main pillar. Whether there's any effect fro the shed cooling and then the woodburner heating up again… well i'll see how the sideways tram is tomorrow.

I also didnt have the quill lock engaged last time which might also affect things.

0.03mm over 18cm.. well the widest cutter it's rated for is 80mm and at that the sideways variation would be 0.014mm'ish ..just over a half thou in imperial over the cutter face. So for a tyro about to skim his first metal it's close enough.

Incidentally my first message math was near enough -.shim thickness half the DTI difference proportioned to the DTI spread compared to column bolt spread.. although i drew a cheat pic to get my head around it. It may still need to be shimmed..but no point rushing into that.. a few more days of checks and measures to see if anything moves. I still have to check quill lock on/off and indeed whether how far the quill is out matters

[Author]

Posts