Fitting DROs to small mill

[Robin GrahamParticipant @robingraham42208]

Hi. This has probably been addressed before, but I've not found a directly relevant thread. I've bought two linear scales and a readout unit from ARC (their 'standard' range) with the intention of fitting them to the X and Y axes of my WM14 mill. Because everything is so cramped on this little machine some ingenuity is going to be called for to to fit them, so I'm probably going to be asking a few questions. First off though: is it OK to cut the beams down? I can't see why not, but thought I should ask because I don't fully understand how these things work. Second, if so, how? The beams are marked "Stainless Hardened", so presumably not with a hacksaw?

Any advice appreciated, regards Bob.

[Robin GrahamParticipant @robingraham42208]

[Michael GilliganParticipant @michaelgilligan61133]

Bob,

You might find something amongst these.

MichaelG.

[dcostaParticipant @dcosta]

Hello Bob, good morning.

I also bought my scales from ArcEuro Trade (the kind with remote display) and cut them with a small PROXXON angle grinder.
They work very well.

Best regards
Dias Costa

[Bob PerkinsParticipant @bobperkins67044]

Hi Bob

i think there have been a few threads on this topic. I fitted scales to my sieg mill last year and they really made a difference. It was a squeeze but I wasn't too worried about location as I bought a remote display panel for them so I don't need to get to them to change batteries, only to press the on and zero buttons. I didn't protect the displays and have cracked the glass on the x axis. It's not a problem as I read the values off the remote display anyway. I've put some insulation tape over this to protect it. After I installed it I found it made access to the screw that locks the table tricky. I've since moved it when I installed my power feed.. There are some photos in my albums.

regards

Bob..

Edited By Bob Perkins on 18/01/2014 06:53:05

[HowiParticipant @howi]

Hi Bob

I have just fitted scales from Arc, Igaging ones I believe, that have a remote reading head, mainly inspired to do it by the touch dro project by Yuri – Google touch dro for his site.

I have the super sx2 mill, not sure how this stacks up to the wm14, but I found it very easy to fit the scales.

I have the y axis scale on the left, the x axis at the back and the z axis on the left hand side of the column.

This avoided reducing access to the GiB screws, I also removed the arm and spring assembly on the column to free up space as it did not seem to be doing a great deal, the head still moves OK without it.

I have used an old bicycle inner tube cut down and split along length and super glued to the brackets to protect the scales from the usual crud.

Tested everything out by using touch dro to drill 6 holes on a PCD – so easy! Unbelieveable. Well worth the cost and effort (which wasn't much in either case)

Good luck

With your conversion

[Rik ShawParticipant @rikshaw]

Hello Bob

I fitted similar scales to my WM16 and had probs. First, being to long I had to cut one down. An expensive German bi-metal hacksaw blade cut OK but went blunt three quarters through. I had to use an abrasive cutting wheel in my Aldi/dremmel to finish the job.

That was the easy bit. Time now to drill the base casting. Easier said than done because as in the case of two of the holes the casting was so badly chilled it was like trying to drill glass. The solution was to get through the nasty hard spots with a diamond mounted point in the dremmel after which the tapping drill and tap were able to do their work OK.

Sounds easy? It took me hours. Hopefully yours will be easier to fit.

I keep my scales covered with strips of polythene as I have read on here that coolant and swarf/dust can kill these cheaper scales. Nevertheless, just before I locked up last night I noticed that one of my scales seems to have given up the ghost. After struggling unsuccessfully for several hours trying to rectify problems with my ailing old milling vice I simply could not be bothered investigating further.

I'm feeling a bit like "Unlucky Alf" from the Fast Show – Oh Booger!

Rik

[mechman48Participant @mechman48]

Hi Rob

Have a look at my album 'DRO' on how I fitted my DRO's to my WM16, didn't have any probs apart from the X axis which interferes with the stops as having to fit the head where the central post goes, what I may do in the future is move it to the rear of the table & reinstate the stops but so far have managed fine as is.

George

[Oompa LumpaParticipant @oompalumpa34302]

I have made new end brackets for my X axis DRO and I have decided to move this and refit it to the rear of the table.

Siting it on the front seemed like a good idea at the time but now, having had it there for a little while I have decided the rear is a much better place for it. I will lose about 12mm on the Y axis but it is a small price to pay I think.

graham.

[Robin GrahamParticipant @robingraham42208]

Many thanks all for advice/links – all useful stuff and a lot of reading to do! I have a Dremel-type tool and a diamond blade, so shall attack the beams with that.

I was planning on putting the X-axis on the front and sacrificing the stops, so as not to lose Y-axis travel, but in view of comments might rethink. The machine has tapered gibs, so no problem of interference with adjusting screws, but the X – axis lock screws are just a bit too close together to get the reading head between, so it would circumvent that problem as well as allowing me to retain the stops..

I got as far as trying to drill the base casting today, but ran into the same problem as Rik – the b****r really is hard. Tried a masonry bit sharpened as best I could by hand on a diamond stone, but that hardly touched it either. Eventually made some headway with a diamond burr in the Dremel, but it's slow going! Rik, do you recall how deeply you had to excavate before you could drill/tap with HSS? I've got in about 2mm, but it's still not yielding to an HSS drill.

Regards, Bob.

[Gone AwayParticipant @goneaway]

Posted by Howard Winwood on 18/01/2014 09:37:13:

…….. the x axis at the back

Did you manage to do this without reducing the travel in the Y-axis ?

[HowiParticipant @howi]

Yes! Because the scales have a remote reading head the sliding part can be vertical ( same on all axis) so does not compromise the travel. You would need to put your table y axis as far back as poss and see what room you have to mount the scale. I would rather lose a bit of travel than not be able to adjust or lock the gibs.

[Rik ShawParticipant @rikshaw]

Bob – I used a cylindrical diamond burr approx. 3mm dia. and used it in "drilling mode" until I had gone in around 6-7mm deep. I took it reasonably steady to preserve the burr (and the mini drill) and eventually it did the trick and allowed the drill (Dormer HSS) to get a bite. Once the drill had reached the bottom of my excavation it was able to drill down deeper to the correct depth without a problem.>>

I also tried a masonry drill which was a waste of time, even experimenting with re-grinding the tip geometry had no effect on the casting.>>

I got over the problem of the table locking nuts fouling the scale by discarding them and replacing with my own version.

>>>>

I drilled out the tip of the studding and Loctited a brass slug in so as not to damage the ways.

>>>>

I also use an X and Y remote display but find that the mini USB plugs that plug into the scale reader units are so sloppy they keep falling out. Have tried blue tack but without much success. I suppose I could use a small screwdriver to splay the connectors the better to make them fit but I am a bit windy about naffing things up.>>

Rik >>

[Robin GrahamParticipant @robingraham42208]

Thanks for that info Rik. I'd been scratching away with a small round burr, which works but would take forever to get to that depth. I'll get a cylindrical one and/or a solid carbide bit. I guess even if I can't find metal soft enough to tap I could epoxy a threaded stud into the hole.

Replacing the Bristol locking levers as you have done looks like a good idea anyhow – on the WM14 at least they tend to get in the way even without the extra gubbins of the DRO.

I'd noticed the iffy fit of the mini USB plugs just playing with the things on the bench. Gaffer tape springs to mind!

It'll be a couple of days before I get the bits to carry on with this now, but thanks to all for help so far.

Regards, Bob.

[Douglas JohnstonParticipant @douglasjohnston98463]

Solid carbide drills are pretty good for this kind of task and also for drilling holes in the hardened stainless steel scales. The only problem is chipping of the cutting edges since they are rather brittle. I picked up a box of carbide drills, all with 1/8 inch shanks and various diameters up to about 6mm, many years ago and they have got me out of quite a few problems with hard materials.

I did a similar mod to Rik on my Myford VMB mill to keep the scale on the front of the table and still be able to lock the table. I too thought of fitting the scale at the back of the table but prefered not to lose Y axis travel.

Doug

[Gone AwayParticipant @goneaway]

Posted by Howard Winwood on 19/01/2014 08:17:42:

Yes! Because the scales have a remote reading head the sliding part can be vertical ( same on all axis) so does not compromise the travel. You would need to put your table y axis as far back as poss and see what room you have to mount the scale. I would rather lose a bit of travel than not be able to adjust or lock the gibs.

The answer in my case (on my WM16 lookalike) is none at all. I can run the Y-axis back until it crashes into the bracket holding the way-cover (which I've already skinnied down to the bare minimum).

I'm not willing to compromise on Y-axis travel (I'm surprised that anyone would actually). Frequently I want more than I have. So I mounted my (glass, with separate DRO) scales at the front. I extended the gib-screws out past the scale in the same way that Rik shows above so I didn't lose the use of those.

What I have lost is the ability to mount the limit-switch box for my X-axis power feed in its intended location. I haven't figured out a suitable alternative so I run that "open-loop" (is there a smiley for "…gulp! " )

[Robin GrahamParticipant @robingraham42208]

Report on progress. I bought 3.5 and 4mm solid carbide bits from eBay for about a fiver apiece. I was a bit worried about the low price, but encouraged when one drew blood from my finger as I was trying to extricate them from the packing. Dunno how long they will stay that sharp, but I have now drilled and tapped M4 with hss into the hard base casting. Without breaking anything!

thanks yet again, Bob.

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