The Home Machinist!

I decided to stick a DRO on my lathe. My cunning plan went like this: Buy a 3-axis DRO that matches the 2-axis job on my 9x49 mill. Buy scales to match the lathe. Buy a z scale for the mill. Stick the z scale and the new display on the mill. Put the old 2-axis display on the lathe, with the new scales. This was a lot cheaper than doing both machines from scratch. I hope.

Question: does anyone know the "standard" place to put a mill DRO z scale? It looks like it should go on the left side of the machine, but I went Chinese, so I have no instructions to speak of.

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I stand corrected (how unusual). The seller just emailed me installation directions. I had no idea they even existed. I may be able to pull this off. I will upload the PDF, in case anyone else ever needs this. It's for scales that fit a Sino SDS6-3V.

Whoops, the file is too big. If anyone knows of good place to put it online, let me know.

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Hi Steve,
I would be interested in having a read of that file. I have the Sino and the Meister ones here if you need them. Mitutoyo, Easson and a few others are on line and the DRO pros has a good site. I understand what you doing buying the 3 axis DRO readout for the mill, but 2 scales for the lathe and 1 for the mill.

It doesn't really matter which side you install the scale, but I think it's best away from your knees lock handles if you have them (as some Bridgeport's don't) and on the non gib side of the knee because there is less movement.

The one on my machine now (same as the G3617) came factory fitted to the right hand side looking from the front, but it is close/interfering with the knee locks and is also on the gib side, so I am going to move it over to the other side one of these days (soon).
They fitted mine their because of the electrical box was in the way on the other side, but I don't know why they didn't just move it back like I had done already, after all the DRO was factory fitted.

Dave

If you have Sino materials, you may already have what I have, but I would be glad to email it to you, if you provide an address.

I didn't think about the gibs. There's some kind of lube thing on the right side of the machine, and the gib handles are on the left side. Maybe the right side is the place to be.

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I probably have it if it is the Sino one, I was just curious.

What I have found, is the bracket for the reader head usually goes in between the gib locks on the knee, and stops the gib locks rotating around and also makes things cramped. You might have more room on yours.
One guy mounted his reverse. He made up brackets from the knee to hold the scale, then mounted the reader head directly to the column.

Dave

I'm glad to learn I can mount it on the right side. I have a lot of crap on the left side of my mill!

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Hi Steve,
You might find you need to move something to fit the scale, but the factory just put things where they are convenient for them to mount, without much thought.
Another thing to keep in mind, is to mount the scale and reader head as close to the way as possible. Otherwise you get a high leverage effect when tightening the locks that will have you chasing numbers on the DRO, like the picture at the bottom shows.

The X axis is fine because you can get the scale on one side and the reader head on the other on the way. The Y axis you can usually get pretty close, but it doesn't have the rocking movement like the knee does.

I only mention this because I saw the install in the link below and thought it was getting too far away from the way, and will get problems when tightening the locks up. I get some movement on the DRO when tightening my knee locks, and mine is as close as possible (about 100mm)to the way.
http://bedair.org/Mill/6760mill9.html

This fellow mounted the scale directly on the knee and the reader head on the column, so no problem their as it's like an X axis set up. The only trouble is it leaves the scale out where it might get damaged.
http://www.boysungrain.com/dro-z.htm

And here are some lathe installs I thought you might be interested in. This first guy cut through his carriage for the scale cable to run through, I don't recommend it at all, but you might get some other tips from his install.
http://bedair.org/Grizzly12x/DRO/GrizzlyDRO3.html

My scale cable runs similar to this below, going under the cross slide to the chuck side and then over the back.
http://www.boysungrain.com/dro-2l.htm

There are also a load of installation pictures in the link below, just click on showcase lathe or mill on the right and it will bring them all up.
http://mtechdro.blogspot.com/

I bought my first readouts about 4-5 years ago, and since then keep my eye out to see what ideas people come up with. The links above are probably the best step by step ones around.

Dave

Wow, thanks for the pictures and links.

While I was studying up on this, I read that you can get significant errors if the scale is not perfectly parallel to the movement of the table. That makes me wonder about the accuracy of my existing x and y scales. I doubt it will make any real difference, given the small scale of the things I do, and the low degree of required accuracy, but it's something to think about.

Right now, the big priority is to get the Disco Garage cleaned up to the point where I have room to get this thing installed. And I still have to fix my power feed.

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LOL,
Thanks and I am glad they helped. With the scales already installed, just place an indicator on the scale housing (top or bottom) and also check the side, then run the table both directions and see if it varies. Most aluminum scale housings are not perfectly true so you can only go so far, but as close to zero movement as you can get, it should be a maximum of around 4 (0.01mm) thou from end to end.

You can see the Easson installation manual in the link below, but it is only a basic one. Just click on brochures & manuals down the page.
https://www.machineryhouse.com.au/D722A

You can see the dial indicator set up in pictures 14 and 15 in the thread I posted about mounting it to the front of the table.
viewtopic.php?f=43&t=84767


Dave

This thing is already turning out to be a challenge. The scale and cover are about 24" long. The scale is 470mm, which is probably the correct fit, since it has to be somewhat longer than the 16" (406 mm) travel of the knee. The scale and cover will not fit on the knee, so they'll have to go on the mill body. The problem is that the cover on the scale has to open toward the rear of the mill to keep crap out of it, so the reader will be on the side of the scale to the rear of the mill. That means the knee is on one side of the scale, and the reader (attached to the knee) is on the other. I guess I'll have to rig it so an arm reaches around behind the scale and holds the reader, as the guy in this link did.

http://bedair.org/Mill/6760mill9.html

I am a little nervous about tapping the screw holes. I have a hand tap and one of those things that attach to a drill press, but I don't have anything that assures a perpendicular orientation when working on something like the mill, which clearly can't be laid on a drill press table. Maybe I have to buy a new tool. Darn the luck. I just hate getting new tools.

I checked the Easson manual, which seems to apply to pretty much the same DRO stuff. It says to attach the scale to a machined surface. HAHAHAHAHA. I love engineer humor.

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By the way, will anything bad happen when I crank the table up to the maximum height? It's giving me the willies. My mill is not bolted to the floor.

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You should be right lifting the knee all the way up if the table is in the centre, even if it wasn't it should be right. What type of mill is it, or did I miss that somewhere.LOL

Thats the way the scale needs to face, and my factory install is the same but uses aluminum brackets, I will grab a picture latter.
When I installed it on my first mill I used flat bar to do it, but didn't make it as long on the knee as that guy and I don't think it needs to be.
I had to pact the top of my scale out because the column tapers in, you can either use a piece of scrap mill to size or use 2 jacking screw. Even if you use a packer, 2 jacking screws are good idea as they allow you to adjust the scale.

As for tapping you should be fine as cast taps easy. They use M5 for factory installs which are only a tiny hole. There is a gadget sold as a taping guide, but you can just drill a 5mm hole through a short piece of round solid to use as a guide.

Dave