New Ultra Small DRO just installed

Groundhog said:

Are those the "Magna Slim Scales" with the super small read heads and scales? That is the part of the system I like.

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Just looking at the pictures it looks the same-



I think it shows 20mm wide on the spec sheet they sent me.

Andgot
Those are regular sized scales. NOT the small ones like I have. See the end caps and the mounting blocks? They will take a lot more room.

If you have a smaller machine or special requirements like I had I strongly advise you to do some research and at least consider the smaller scales and read heads.

They are Electronica brand “Magna Slim Scales” (magnetic) and Electronica brand EMC14A reader heads.
Reader heads measure 1.42” x .51” x .55 compared to 2.37" x .89" x about 1" (couldn't find a measurement).
Scales measure .59” high and .28” thick compared to 1.1" x .4"

With the Magna scales if you want to read 6" of travel you need 6" of scale room. Period. Just an area 6" long x .6" high. With conventional magnetic scales you need an area 8" to 10" in length and 1.1" high to install.

The fact that the Magna scales are available, the same or less cost and made by a reliable manufacture make it a no brainier to me.

By the way - in the original post I said that I was somewhat concerned that no cover was recommended for the scales. Now that I have used them for awhile I agree and see no reason to need a protective cover.

Very cool mod! How did you adjust the scale on the bed to run parallel with the read head ? I dont see any spacers so I assume it was close enough?

Hey '98 Z28 -

That is the part that is hard to explain and even harder to believe until you see it. Dan (DroPros) told me just to worry about getting the ends the same and the rest would take care of itself. I had a hard time believing him. It all seems too flexible to work that way - and the center isn't even attached to the ends except with the magnetic strip (which is flexible).

But it really does work! And it doesn't matter what the shape of the bed is - the ends are all that are important because the center floats over everything between. (The ends have to be higher, or equal to any high spots.)

Just use a dial indicator on your carriage and get one end set in place (parallel and perpendicular) then go to the other end and do what is necessary to make that one the same (shim more than likely). Then insert the center parts (the magnetic strip mounted in the center extrusion), install the stainless protective strip over the whole thing and you are done!

Hi Groundhog

I just found your thread while researching a DRO for my Grizzly G4003G. It looks very similar to your HF.

My issue is the cross-slide gib lock is right on the surface where you have your X-axis scale. Did your discussions with DroPros cover such a scenario?

Mark.

jmarkwolf said:

Hi Groundhog

I just found your thread while researching a DRO for my Grizzly G4003G. It looks very similar to your HF.

My issue is the cross-slide gib lock is right on the surface where you have your X-axis scale. Did your discussions with DroPros cover such a scenario?

Mark.

Click to expand...

I've got a PM1236 that is similar with the cross slide lock on the right side. I never use the cross slide lock so I did not care about covering it with the dro scale.

I've seen someone replace the set screw with a hex head bolt & made spacers for the dro scale so they could still access the cross slide lock with an open end wrench.

Edit: Here's the thread:

I do not like the idea of a cross slide scale on the tailstock side of the carriage. Good way to destroy it, and to not let the tailstock get as close as possible to the work. I understand that the mini scales can fit under the cross slide on some lathes, which sounds like a good idea if it does not interfere with anything.

Bob Korves said:

I do not like the idea of a cross slide scale on the tailstock side of the carriage. Good way to destroy it, and to not let the tailstock get as close as possible to the work. I understand that the mini scales can fit under the cross slide on some lathes, which sounds like a good idea if it does not interfere with anything.

Click to expand...

I can relate, I've ran my TS into the read head before but it just hit the 2 mounting cap screws. I just put a couple of rubber bumpers on the TS for now until I make some type of better bumper.

Not much of an option unfortunately, most choose to mount it on the right side if you still want the ability to use a follow rest.

I believe it was @JimDawson that mounted his scale under the cross slide. That was a pretty cool idea, never seen that before.

Hi Splat

I looked at the hole on the chuck side of the cross-slide but there is no gib over there on my machine, so the point of any screw would drag directly on the internal dove tail, Plus my follow rest mounts on that side, so I think that is a no go.

The solution in DarkZero's link is interesting, particularly for the older magnetic scales, but after further contemplation, I think I may move my gib screw towards the front of the lathe about an inch or so. Then there should be plenty of room to mount the new shorter super-slim magnetic scales on the aft side of the gib screw (see pic below), and the read-head on the aft "outrigger" of the saddle. Will likely have to remove the cross-slide to drill and tap the new hole for the gib screw but that's no biggie. My cross slide travel is only about 6-1/4 inches.

Bob Korves makes a good point about the tailstock crushing the scale and/or read head though. Maybe a simple bumper will prevent that, but the tailstock will then have a shorter reach as Bob points out. Either way, I think I'll change the gib lock lever to a screw and use a dedicated little box end wrench. The lever is kinda clumsy.

The whole shooting match could be mounted on the chuck side of the cross-slide, but then it will be under a shower of schmutz all the time, and you run the risk of crashing the scale/read head into the chuck.

Will try to find reference to Jim Dawson's solution.

I'll call DroPros next week for more info. I really like EL400 digital head I've had on my mill for about 6 years. Won't be too happy to change heads but alas.

With the mini-scales the lock is just below the scales. My lock is a hex screw and not a handle (easy to swap one for the other) and I use a hex wrench to lock it. I don't use the lock often anyway.

(As mentioned somewhere above) The mounting bolts for the head act as bumpers for the tail stock. I suppose if you really tried you could ruin something, but if you are that rough with your equipment you are going to ruin something DRO or not.