View Full Version : mounting a dro on a 12x36 lath

01-23-2012, 10:20 AM
hi guys just picked up a dro for my 12x36 grzzley / busy bee cratex lath just wondering if any one has put a dro on one i do not what to re invent the wheel if i do not have to if some one has done this before any ideas pictures wood be nice thanks ironjohn

01-23-2012, 11:35 AM
But have you tried doing a search? I haven't done it, but I'm sure there are LOTS of posts by people who have. Later.


01-23-2012, 02:10 PM
Here's one data point for you:


David Merrill

Ron of Va
01-23-2012, 03:49 PM
I mounted a DRO on a Grizzly G4003G and took a bunch of photos, and did a write up for someone else. Send me your email address and I will forward the 9 emails it took to send the report. They have a lot of photos which might be helpful.

Davo J
01-23-2012, 11:38 PM
Any chance of making a post up? I fitted mine about 5 years ago but would be interested to see yours.


01-24-2012, 01:58 AM
Ron, I would like to see that as well. Have not done mine yet.

Ron of Va
01-24-2012, 06:39 AM
Part 1 of 8
The DRO I mounted was the Esson 10 two axis unit for the lathe. It came with a four parts for the X axis (cross slide): an aluminum backing plate for the scale, the scale, and the scale reader and a cover which I did not use. The DRO came with three parts for the Z axis (carriage travel); the scale, and the scale reader, and a cover.

I started the installation on the X axis. First I determined where the backing plate was going. I couldn’t just mount the scale to the cross slide because there are several places on the cross slide you shouldn’t drill and the scale has fixed mounting holes. But you can pick and choose where the backing plate mounting bolts go, then mount the scale to the backing plate drilling and tapping holes anywhere along the aluminum backing plate you want.

The aluminum backing plate for the X axis is too long, so I had to cut it off.
I had to remove the tail stock to facilitate the installation. I also laid down a layer of duct tape to act as a spacer for the backer bar. This keeps the backer plate up off the carriage a few thousandths of an inch so it will not rub as you move the cross feed. The tape also catches most of the drill swarf from the holes.

One photo shows areas where drilling would be hazardous. Those areas are marked with orange tape. Those areas are the gib screws on each end, the recess for the compound hold down screws, and the oil port support pin. (I think that is what the center pin is for)
One photo shows the location of the gib, and how drilling too deep or in the center of the compound rest could strike the gib.

One photo shows marking of the holes on the backing plate.

If along the way you have any questions, just ask. Also if you want a different view or photo from a different angle, I might have one.


Ron of Va
01-24-2012, 06:40 AM
Part 2 of 8
After marking where the holes in the X axis backing bar went I drilled the backing bar at the drill press. Then I used a drill bit to mark exactly where the holes went on the cross slide. I used a square on the cross slide to eyeball how square I was drilling the hole. I drilled and tapped the holes on the cross slide, and countersunk for flathead bolts on the backer bar.

The backer bar is wider than the cross slide and stands higher but it will not hurt anything.

Ron of Va
01-24-2012, 06:42 AM
Part 3 of 8
I marked then cut the end off the backer bar, flush with the cross slide in the front. Then drilled and tapped the backer bar for the scale, making sure the scale would be a few thousandths above the carriage.

After mounting the scale, I wanted the scale reader in the center of the carriage saddle.

I marked the location of the holes for the reader. These holes you have to be careful with, because the adjustment for the reader mostly comes from moving the scale, and remember you only allowed yourself a few thousandths of an inch above the carriage for the scale. If you screw these holes up and drill them too low, you will have to move them left or right to re-drill and tap. But don’t re-drill and tap until all is finished, because there will be some adjustment up and down after you remove the blue plastic safety spacer between the reader and the scale. Not a lot, but some.

The reader would need shims behind it to stand proud of the saddle and align with the scale.

The photo that shows the shims on the X axis reader the screws are different. Those screws are 8-32 X 1-1/2, if I recall correctly. I had an 8-32 tap, and the #8 screw would pass through the hole in the reader without engaging the readers’ threads. Most everything else is metric. The problem with the readers’ threads was that when you need a metric bolt about 1-1/2” long, the threads only go up the shank about half way. So you can’t screw a metric bolt in all the way, it gets stopped at the unthreaded shank and won’t reach the saddle.

The spacing was determined by putting the Scale in its place, and holding the “Reader” against the bottom of the Scale, then I reached up from underneath with a gang of feeler gauges until the spacing was determined.

I used some aluminum rod I chucked up in the lathe and cut the shims to length (first I drilled a hole in the end for the bolts). I used this dial indicator pressing against the cross slide to make sure the shims were the length I wanted. http://www.grizzly.com/products/Magnetic-Base-w-Indicator-1-Travel/G9623 The spacers weren’t very long, you can see in the photo.

As you can see from the photo, the metal cable is going to be a pain in the ass to deal with. It will put stress on the reader every time you run the carriage back and forth. I had to deal with that.

Ron of Va
01-24-2012, 06:44 AM
Part 4 of 8
After mounting the X axis scale of the Easson 10, I decided to deal with the cable. I decided that the best way was to make a cutout in the carriage, and mount it under the scale.

I first used a hacksaw to make two parallel cuts the width of the cable. Then I used a drill making several holes straight down between the parallel cuts to hog out most of the material. A couple of more cuts with the hacksaw took out some more material, and finally some files to make it clean. It took about an hour.

As a gauge, I determined that an “O” drill bit would give the proper clearance as I worked the slot to depth. It was then I realized that the shielded cable arched up in the slot and would rub the bottom of the “Scale”. I either could cut the slot deeper to lower the cable so it wouldn’t rub, or use some kind of hold down to keep the top of the cable flush with the saddle cutout.

I decided to use a hold down. I started by drilling for a 6-48 cap screw. I made sure the hole was close enough to the edge for the countersink in the next step. These screws are mostly used on riflescope rings, which I already had drills and taps. Next I used a larger drill bit to create the countersink, making sure the side of the larger bit stuck out into the saddle cutout. I then flattened the bottom of the countersink with a Dremel tool, and fashioned the hold down.

If you don’t want to go to all the trouble to notch the carriage, you could drill and tap for a screw on top of the carriage, and use a cable tie around the cable and screw to keep the stress off the cable. But it only took me about an hour to make the cut out. Cast iron is easy to work. I think it is cleaner and looks nicer, plus the hold down has a good grip on the cable, and it is not going to move.

Ron of Va
01-24-2012, 06:45 AM
Part 5 of 8
Here is the finished X scale.

Ron of Va
01-24-2012, 06:46 AM
Part 6 of 8
The Z axis scale has some slots for the mounting holes for fine adjustments. I leveled the lathe with a Starrett precision level, and then used this level to help mark the holes. You can also use a tri-square. Once the scale reader is installed and tightened down, you run the carriage to the end of the travel, feel the reader float inside the scale, (the reader is fixed at this point) then tighten down the scale mounting bolt. Making sure there is no binding with the reader. I did put a washer between the scale and the base castings so if any oil that dripped down would work its way behind the scale, and not drip over the top and get into the scale reader.

When installing the Z scale, I made sure I didn’t mount it too close to the head stock, and interfere with the installation of the splash guard

I cut a piece of aluminum with a jigsaw to replace the cross slide cover on the back of the saddle. The bolts in the photo at the top were the same bolts used to hold the original cover in place. Then I turned my attention to the reader.

I then marked the location of the M5-.08 X 1-1/2” hex screws that will secure the “Reader” to the aluminum plate. These screws did not come in the mounting kit; I had to find the right bolts in the right length to fit the threads in the reader. See the bolt at the bottom of the photo; I marked the plate using the screw location on the side.

I left the blue spacer in place and screwed one of the hex screws into the reader. I then marked the center of the screw shank on the plate to indicate the height of each hole as it relates to the plate. Both hex screw hole heights were marked independently since I could not guarantee how square I had cut the plate. I then drew a line between the marks, and after removing the Scale and Reader, I used the “Reader” to locate the holes over the line. I tried to hit the location dead on, and got lucky. I could always go back and create an adjustment slot in the plate, or simply enlarge one of the holes, or move the scale up or down. I knew the error would be very small, and should be easy to deal with. Note: Moving the scale up or down in the slots would require both ends to be moved and kept in parallel to the carriage travel.

After drilling the holes in the aluminum plate for the reader mounting bolts, I needed to determine the length of the spacers between the aluminum plate and the reader. I used a dial caliper. I used the depth feature of the calipers to measure the depth through the plate to the reader. Then subtracting the thickness of the plate, I determined the length of the spacer. The spacers were made for the Z axis the same way they were made for the X axis.

Ron of Va
01-24-2012, 06:47 AM
Part 7 of 8
I used a piece of oak to act as a guide bar to secure the cables. See the photos
I finished by mounting the cover over the scale. There is no photo of the cover installed.


Ron of Va
01-24-2012, 06:49 AM
Part 8
I checked everything and made sure everything worked.

I took the Z axis aluminum plate off and removed the reader. I then mounted the cover over the scale. No photo.

The DRO display can be mounted on top of the electrical panel box, or on the back of the panel boxes’ removable cover. I chose to mount it on the back cover. Although I regret that I mounted there. The unit is heavy, and some consideration should be made for sag. I thought that one or two degrees out of parallel should take care of it. The unit is only supplied with metric cap screws for mounting. I happened to have a couple of metric nuts and washers for the inside of the panel box. I used the supplied cap screws, and my nuts and washers for this mount.

After I moved my lathe against the wall, I made an L bracket out of wood for the display to rest on. I did this because I started having sagging problems from vibration during use. The display would vibrate down and touch the back splash. No photo.

This concludes the instructions.
I hope it is useful.


01-24-2012, 09:09 AM
hi ron you did a nice job on the mounting the problem i have is the scales that i have are to tall to do what you did and i will have to come off the back of the cross feed and thats some thing i will have to come up with thanks ironjohn