X2 Mini Mill backlash, and parts supply etc

[Jim BaxterParticipant @jimbaxter34386]

Sorry Michael I'd missed your previous comment to that effect, and the one following it!!

Not entirely sure if I'm honest. I've only got a cheap thread pitch gauge so it's entirely possible I suppose. I don't have a 16tpi one to compare, but it might be the case that the impending box of goodies includes a tap like that, which I can test against the thread, and see which is the more snug fit.

And if Arc do stock spare ones then it'd be sensible to get one I guess.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Jim Baxter on 06/11/2013 00:31:50:

… I've only got a cheap thread pitch gauge so it's entirely possible I suppose. I don't have a 16tpi one to compare …

.

Jim,

I would suggest that you simply measure, as accurately as you can, the length occupied by a [large] whole number of crests of the thread. This is inherently more accurate than using a pitch-gauge, and it will also average-out any differences caused by wear.

MichaelG.

[Les Jones 1Participant @lesjones1]

Jim,
If there are dials on the end of the leadscrews you will be able to see how much one revolution of the handwheel moves the table. If not start with the edge of the machine vice about 60 mm from the spindle. Turn the handweel a few turns to reduce this distance to about 50 mm. Measure this distance with digital calipers and note the reading (Reading 1). Turn the handwheel ten turns in the same direction as you turned it to reduce the distance from 60 to 50mm. Measure the distance again (Reading 2) Subtract reading 2 from reading 1 and divide the result by 10. This will be the pitch of the leadscrew. DO NOT reverse the direction yo turn the handle at any point during this test. If you do then start the test again.

Les.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Jim Baxter on 05/11/2013 19:40:08:

My boss used to be an engineer, and when I asked him today if he happened to have an M16 1.5 tap (I assume I need that for a nut since it's 15.85mm diameter screw and 1.5mm thread), he said he'd have a look. Then pondered a moment and added "actually, I've a whole big box of taps & dies you can have – I'll never need to use them again". Result!!!

Remember you are looking for a "Trapezoidal" tap if it is metric or an "ACME" tap if it is imperial. They have a completely different thread form to standard taps.

Russell.

[Ian S CParticipant @iansc]

If the thread is very warn, it may appear to be a V shape, rather than an ACME, or similar thread. Ian S C

[Jim BaxterParticipant @jimbaxter34386]

Sorry for being so slow to update this topic – been mad busy lately so I've not had a chance to act on the most recent replies re' measuring thread etc. Appreciate the input though thanks, and I will be doing these things when I get a moment to!

No joy yet on taps etc as they've failed to materialise alas, but I don't think the right one would have been in there anyway. Since cutting a slot in the existing X- axis nut doesn't seemed to have ended well (not sure why as the Y axis one seems to have helped), I'll have to order a new X nut from somewhere. I think I read on one post that Arc sells these?

Anyway, I'm now the owner of a peugeot 106 bonnet strut so I can copy 's version of the Z-lift conversion. The strut I've got seems way too long for the job but that will presumably be down to how it's mounted. I need to go and study the pictures for what brackets need making basically.

Plus I think my belt conversion has arrived at last. Yay!

[Jim BaxterParticipant @jimbaxter34386]

Yep – got my belt conversion yesterday and fitted it last night. Very pleased!

This is the version I got: http://www.mbbilici.com/?p=85

I had to modify the metal guard behind the fine feed on the Z axis as one of the bolts on the kit was in the way of this, but apart from that it was an easy install, great fitting parts, and a great end result. Very helpful bloke (in Turkey) that sells the kits too.

Hopefully I will be able to get my 'air spring' fitted imminently too.

One thing that's also apparently is I need a clamping kit for my mill as the litre vice I've got is no use for wide/oddball shapes of course. I tried milling a heatsink for a peltier 'eco fan' I'm making earlier and it jumped out of the vice as it couldn't hold it firmly enough. Could have been painful!

[Danny M2ZParticipant @dannym2z]

G'day.

I have an X2 mill. The leadscrew is 1.5 mm pitch ( 10 turns = 15.0mm). Backlash is 8 divs of the dial (8 x 0.025mm) about 9 thou. For what I paid for the mill this is quite acceptable. Just keep the gibs tight and if you overshoot then back off a bit and sneak up to the setting. Just for interest, try leaning on the head when flycutting. This shows up the flexibility of the design.

Regards from the land of the kangaroo

* Danny M *

[Jim BaxterParticipant @jimbaxter34386]

Thanks Danny – more useful info.

Sorry for the slow updates again. I'm no further on with backlash issues, but I now have a nice clamping kit and 3" Toolmakers precision vice, which is a lovely chunk of metal!

Air spring is also fitted and I'm very pleased with that, so thanks for all the assistance chaps.

[Richard Wilkins 1Participant @richardwilkins1]

Please could anyone inform me as to whether or not you can get replacement lead screw nuts for the X2 or SX2.

[JasonBModerator @jasonb]

I'm 99% sure you could get those from ARC they do them for the SX2P which I think uses the same bits, e-mail them and to check.

J

[Danny M2ZParticipant @dannym2z]

G'day.

I have read online about stiffening/damping the column of a light mill (such as the X2) by filling the column with a dense medium such as epoxy mixed with granite etc. Is this worth the effort? Has anybody actually tried this?

I am 'comfortable' with the limitations of my X2 mill, so am reluctant to stuff it up with an experiment. Any ideas?

* Danny M *

[John Weight 1Participant @johnweight1]

Re fitting DROs to an X2 mill, I've recently used cheap scales with integral readout display. You have to be prepared to fabricate special brackets, remembering to allow for front overhang of a machine vice, which can obscure the display. The cost was without counting the brackets was around £60. It's so nice to be able to virtually ignore backlash, and work to close tolerances much quicker than previously.

John Crow

[Neil WyattModerator @neilwyatt]

Hi Danny,

As Graham's photograph shows, the fundamental issue is that the column bracket is fixed by three screws that are almost in a straight line. This is compounded byy teh mating surfaces being poorly finished,

I greatly improved my X2 by scraping the joint surfaces to get amuch bigger contact patch (I also corrected a slight lean in the column this way – it was along slow job that turned my fingers, if not the air, blue).

I also fitted a triangular stiffening plate of 4mm steel between the column swivel bolt and two M12 screws and spacers at the rear corners of the base casting.

The improvement in surface finish and rigidity was noticeable and further imprved by fitting roller bearings and belt drive.

I wrote these modifications up in (I think) MEW issue 199.

I'd stress that the newer versions of the X2 with a non-tilt column don't suffer this fault. As mentioned earlier, a conversion kit for the old X2 is available from Arc Euro.

Neil

[Ketan SwaliParticipant @ketanswali79440]

Posted by Danny M2Z on 20/02/2014 22:18:22:

G'day.

I have read online about stiffening/damping the column of a light mill (such as the X2) by filling the column with a dense medium such as epoxy mixed with granite etc. Is this worth the effort? Has anybody actually tried this?

I am 'comfortable' with the limitations of my X2 mill, so am reluctant to stuff it up with an experiment. Any ideas?

* Danny M *

Hi Danny,

This idea is easier said then done. Some have tried it. Mostly they have got it wrong. It has been written up in an MEW issue, cant remember which, relating to the X1 column, and I did sell quite a few SX1Ls as a result of the said article. However, in my personal opinion, it is still a bad idea, and it should not be considered if you have not done this before. The key issue if i recall is timing, relating to curing, and temperature/heat generated in certain cases. I do not remember too much detail but if not done correctly, it can all go wrong very quickly.

You would be better off considering what Neil and Graham have said. If you are considering a new fixed column and base, speak with Steven at Ausee Machines and Tools in Melbourne. He will probably bring it in for you. Rest of the parts you will be able to use from your existing X2, but at some stage you may want to consider a longer Y axis screw, as the Y travel can increase if you use the new fixed column and base.

Ketan at ARC.

[Danny M2ZParticipant @dannym2z]

G'day.

Thanks for all the help. I think that I shall pass on the epoxy filled column!

I am pretty happy with my X2 mill, I've had it 8 years now, so getting used to it's foibles (such don't lean on the head when cutting, allow for the slight backlash). Maybe I got lucky, but it trams accurately to 10ths", 'X' is square to 'Y' and it can flycut aluminium alloy to a rainbow finish. I might try Neil's idea of a stiffening plate though.

One thing that I did discover is that when cutting tools are really sharp (ground, diamond lapped and then honed on a decent stone) the reduced loads on the machine can help to achieve good results.

My only complaint is the sloppy 'Z' adjusting knob, but by keeping the gibs snug and the lock slightly engaged when adjusting it I can live with that. Also, I always adjust the cutting depth in a downwards direction to avoid the dreaded 'head drop' that I have heard about. Even my C3 minilathe turns true and parallel, so I am a happy little vegemite.

Regards * Danny M *

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