X2 Mini Mill backlash, and parts supply etc

[John HinkleyParticipant @johnhinkley26699]

Like Bob, my DROs came from Arc Eurotrade. If I recall correctly, the whole lot, for three axes and including a remote display (desirable, but not essential) came to around £160. Dead easy to fit, too.

John

[Jim BaxterParticipant @jimbaxter34386]

Thanks – I don't know how I missed the ones on Arc's site as I've been looking at loads on there lately but they're actually really good prices from what I can see.

Is there any particular advantage to an 'all in one' display unit for DRO, or is it basically a matter of aesthetics and tidyness?

The reason I ask is that for something in the region of £100 I can get 3 separate ones as per this page (depending on the sizes needed to suit the x2 axis'?):

http://www.arceurotrade.co.uk/Catalogue/Measurement/Digital-Readouts-with-Dedicated-Remote-Display

Or for a neater looking solution I could get these for maybe £150:

http://www.arceurotrade.co.uk/Catalogue/Measurement/Standard-Digital-Readouts

But I'd probably be loathe to spend the extra £50 or so if it only gives me a tidier setup and not some much more useful functionality, as that extra money could otherwise be spent on additional tools etc.

Can't really spare the money for either at the minute, but they'll be on the agenda relatively soon I think!

 

BTW, I cut a slot in one of the brass nuts last night and drilled a couple of holes ready for adjustment screws.  Have got the screws ready but not tapped the holes yet.  I couldn't see how to get the nut clamped in my metal cutting bandsaw so I had to do it by hand with a knackered hacksaw blade and it's a bit wonky, but should work still…

Edited By Jim Baxter on 02/11/2013 11:32:56

[Clive HartlandParticipant @clivehartland94829]

Jim, the function of the all in 1 screen gives you all the functions you will ever need for the DRO's. You get middle readings when you measure from both ends and you get multihole set ups either on the base line or set off at an angle. Many more functions are available, milling inclines and curves (Small flats). Recall of past functions and data.

Single readouts give only the measurement. ( I think)?

Clive

[Jim BaxterParticipant @jimbaxter34386]

Thanks for clarifying those points Clive.

It's a tricky one since currently I'm novice enough to not appreciate what I'd use most of those extra functions for but hopefully in due course I would. So I know it'd be better to get the right setup first time round, but depends on budget. For the most part it'll probably be a long time before I need anything more than basic measuring but then it'd be good not to have to upgrade it all in future for the sake of a bit more money.

Food for thought I suppose!

[John HinkleyParticipant @johnhinkley26699]

Clive,

It' actually the other way around with the DROs that I've fitted and the ones that Jim referenced. The combined 3-axis readout only gives options to zero the display, memory function and change from metric to imperial measurement. The single, dedicated displays have the advantage of being able to select ABS and SET functions. They are cheaper, too.

Jim,

It all comes down to money (doesn't it, always?) and aesthetics. I don't think you'll be disappointed with whichever choice you make.

John

[Jim BaxterParticipant @jimbaxter34386]

Thanks chaps – will have to ponder it for a bit anyway – as I say I'm a bit skint currently. No bad thing though since I normally am impatient and get things on impulse without figuring first what's best.

At least in the meantime I've plenty of fiddling to do with both lathe & mill in terms of setup, and hopefully my belt conversion will arrive soon too.

I bodge fitted a cheap Chinese handheld laser tacho to the mill a couple of years back, and it'd be a nice project actually to remove the circuit & display from it, and machine a proper housing for it all that's attached properly.

Plenty to keep me more than busy until I can get a set of DROs for it. Now back to modifying that lead screw nut….

 

Plus of course I need to find out properly what size DRO I need for each axis to avoid any mistakes and to establish the cost properly.  Of course if anyone felt the need to spoon feed me that info I wouldn't feel upset… 

Edited By Jim Baxter on 02/11/2013 14:53:42

[wheeltapperParticipant @wheeltapper]

Arc have got a lovely 3 axis DRO now.

**LINK**

trouble is it's worth more than the dam' milling machine.

nice for a decent mill tho.

Roy.

[John HinkleyParticipant @johnhinkley26699]

Roy,

I might be tempted to refit with these – if they weren't all out of stock!

Jim,

Re: your belt drive: I ordered one from LMS in the USA. Wasn't 'til I tried to install it that I found that, although the mill spindle was 30mm diameter, the portion where the large pulley sits was reduced to 28mm. Either it was going to rattle a LOT or I had to make a new pulley myself. I made a new pulley! Massive reduction in drive noise – if you take out the gears and another worthwhile modification. As I said previously, my mill isn't the same make as yours so you could well be OK. I hope so.

John

[Jim BaxterParticipant @jimbaxter34386]

Cheers John

The kit I bought isn't the LMS version but this one:

http://www.ebay.com/itm/Sieg-x2-mini-mill-belt-drive-conversion-kit-3-days-delivery-option-/261312598631?ssPageName=ADME:AAQ:US:1123

Specifically it says it is for the Sieg X2 so I hope it's a correct fit, but I ought to have measured first.

Well, I modified the brass nuts as planned and the Y axis one is a big improvement I must say.

The X axis was a bit tight initially (albeit with about half a thou backlash!!) but after winding it right across and back it improved somewhat, however it then had a ton of backlash return somehow. Not great!

If I could make a delrin/acetal nut for it then I readily would as I think the stuff I've got here may be delrin, but haven't got a suitable tap. I suppose it might be worth a try doing it with the method linked to further up the topic, ie using heat etc. But before I do, I'll check the thread pitch/diameter of the X lead screw, and see if I can locate a quality nut that I can order from somewhere.

And I found a 106 bonnet damper on ebay for a tenner so I am going to order that and see about making up some brackets for it to go on the column!

[Jim BaxterParticipant @jimbaxter34386]

Update (as much as for future reference as anything) is the x lead screw on my mill is 15.85mm thick, which equates to 5/8th " I think almost exactly.

The thread pitch on it seems to be 1.5mm. Does this sound about right for one of these?

So I can go on the hunt for a better quality nut from somewhere…..

[Sub MandrelParticipant @submandrel]

I converted my (original style) X2 to belt drive myself, & fitted a column brace and angular ball bearings from Arc at the same time.

It's not hugely pretty, but it works really well, and it would be easy enough to 'pretty up'.

Write up is in MEW 199 and 201.For those without a subscription (shame on you!) the second part of the article is also on the Arc Euro website.

Neil

[Danny M2ZParticipant @dannym2z]

Posted by Jim Baxter on 31/10/2013 21:32:40:

Interestingly, the opposite end of the lead screw to the handle has a large slot machined in it for somethin(on the X axis anyway, but not Y).

G'day Jim. The slot is there to take an X-axis drive dog.

Regards from the land of the kangaroo

* Danny M *

[Jim BaxterParticipant @jimbaxter34386]

Thanks Neil – interesting read cheers

Danny – presume that's for the purpose of hooking up to a stepper motor then?

Friend of mine says he may possibly have a tap to suit this thread so I might be able to make a new nut myself. Fingers crossed…

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Jim Baxter on 03/11/2013 09:07:34:

Friend of mine says he may possibly have a tap to suit this thread so I might be able to make a new nut myself. Fingers crossed…

From your measurements your leadscrew will be 16 mm. x 1.5 mm. trapezoidal thread. It's an unusual one so you will be very lucky if your friend has one. Why they chose 1.5 pitch I've no idea, 75 divisions on the dial isn't exactly helpful!

Russell.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Jim Baxter on 02/11/2013 20:11:36:

Update (as much as for future reference as anything) is the x lead screw on my mill is 15.85mm thick, which equates to 5/8th " I think almost exactly.

The thread pitch on it seems to be 1.5mm. Does this sound about right for one of these?

So I can go on the hunt for a better quality nut from somewhere…..

.

Jim,

If it's really 5/8" diameter … it would be worth checking the thread pitch very carefully,before you go much further.

1.5mm pitch is not far off 16tpi

It may be a "metric" machine, but stranger things have been done for the sake of expediency.

MichaelG.

Edited By Michael Gilligan on 03/11/2013 10:16:43

Edited By Michael Gilligan on 03/11/2013 10:35:57

[Clive HartlandParticipant @clivehartland94829]

I would still drill and tap the block and cut a slot across it first, this would at least let you check and adjust the play in the blocks thread. This would save you a lot of trouble making and drilling and tapping a new block.

The block is shown in the exploded diagram of parts from ArcEurotrade, why not buy one from them?

Clive

[Ian S CParticipant @iansc]

Jim, look carefully at the lead screw, a good bit of the wear you have may well be on the steel thread, grit gets embedded in the bronze nut. Had this problem with a friends Myford cross slide, it was so warn it looked like a V thread we were able to get, at a better than expected price, a new lead screw, and nut. Ian S C

[Jim BaxterParticipant @jimbaxter34386]

Thanks for the suggestion Ian – it's a very valid suggestion except that I doubt in this case it would be at all likely as my mill has never really done much work in all honesty. I've had it a long time but only very minor sporadic jobs over the years.

Possible and worth ruling out though obviously!

[Les Jones 1Participant @lesjones1]

Hi Jim,
Are you sure the backlash is due to the nut and not the adjustment of the thrust bearings on the end of the leadscrew ? (This is assuming that the design is similar to the X3 mill)

Les.

[Jim BaxterParticipant @jimbaxter34386]

There's not really anything that I can adjust like that Les. On the X2 the x axis goes through a big bushing before the handle attaches on the other side of the casting. Doesn't seem to be any play in that from what I can tell.

Will double check it all again though since there's still a load somewhere.

[Sub MandrelParticipant @submandrel]

Jim

Are the feed nuts 'free' to move in the holes in the castings? There should be grub screws to lock them in place IIRC. By the way only having the screw supported at the handle end and the nut may seem sloppy but is sound practice. The feed nut should be locked in place when as near to the handle bearing as possible to ensure good alignment.

Neil

[Les Jones 1Participant @lesjones1]

Hi Jim,
If there are two nuts holding the hand wheel then then it is likely that the end float in the leadscrew can be adjusted. If there is only one nut then adjustment will not be possible other than be means of shim washers.

Les.

[Jim BaxterParticipant @jimbaxter34386]

Sorry for the delay replying.

Neil, the feed nuts are indeed held snug by the grub screws, but other than that they're suspended by the lead screws and not secure at all. The Y axis uses a single grub, and the X axis uses 2.

Les, yes there are two nuts and a washer on the end of the screw to hold on the handle. When you describe adjusting the end float do you mean by the amount of torque on the inner nut, then locking it with the second one?

I'm not actually able to detect any end float in this respect when the nuts are done up correctly and it's not anything I even have to make an effort to set correctly. It seems a good arrangement and good tolerances in that respect. The backlash is I believe 99% from the lead screw nut, and 1% (all give or take) from tiny amount of slop in the handle/woodruff key.

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!!!

[Les Jones 1Participant @lesjones1]

Hi Jim,
There should not need to be any significant tightening torque on the inner nut. It should be tightened until there is no end float in the leadscrew but not so much as to make the thrust bearing tight. the Outer nut is then tightened against it to prevent it from moving. You may have to make further slight adjustments as tightening the nuts together may cause the bearing to become slightly tight. The fact that you cannot detect any end float eliminates this adjustment as a possible cause of the problem.

Les.

[Michael GilliganParticipant @michaelgilligan61133]

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

Sorry for the delay replying.

The backlash is I believe 99% from the lead screw nut, and 1% (all give or take) from tiny amount of slop in the handle/woodruff key.

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!!!

.

Jim,

Sorry to labour this point, but did you double check that the screw thread is really 1.5mm pitch, and not 16tpi ?

[see my previous post]

Nicely played, getting the Taps and Dies !

MichaelG.

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