Grizzly G9249 Lathe Improvements and DRO install

[propforward]

Well, I was all set to start my next engine, and had the castings all out, and I'd been perusing the drawings all week. Here it is = a PMR #4.



But, late last year I ordered a magnetic DRO kit from DRO PRO's and I think it makes more sense to install that and tune up the lathe a bit before starting. I did have a huge lathe upgrade planned, with new 3 phase motor and VFD, but I have decided to go one step at a time. First step is the DRO and to beef up the base. First - DRO.

I had good experience with DRO PRO's on my mill, so decided to go with them again. I agonized over 2 and 3 channel, but I could not see a good way to get a third axis on my compound easily, and I don't think that is so essential anyway, so 2 channel it is. I have a small standalone digital scale for the tailstock.

Here's my lathe, minus the back splash, removed for the install.



DRO box - they pack their stuff well.





The scales are very nicely protected.



The readout:



I'm not going to go into intricate detail on the install, because the DROPRO's website has very thorough step by step video "how to's" and instructions. The really nice thing about the magnetic scales is how easy they are to cut to length, so I can get the cross slide nice and neat.

Here's a close up of the installation area. Unfortunately I'm going to lose the lock - but it is not a very good lock anyway, so I'll come up with a better one.



The DRO kits come with an assortment of aluminum brackets, that are more or less "universal". In practice I have found they usually form a decent starting point, but you get the best out of them if you just accept you'll most likely have to machine them to fit, or make your own new brackets.

For the cross slide I drilled and tapped two M6 holes in the saddle, and mounted this chunky L bracket. It is deliberately off center between the bed rails to allow the cross slide to go full travel in both directions without the read head hitting the ends of the scale.



Being able to drill the scale mounting holes in the mill is nice. Won't be able to do that on the saddle scale.



View of the scale before cutting to length - here I have removed one end cap and marked out the cut line.



I just cut the excess off with my bandsaw, which works just fine. Then it's a matter of drilling and tapping a couple of holes for the mounting screws.

fast forward - here is the scale installed, and I've milled down the top of the bracket to hold the read head. Next step will be to drill and tap two holes in the top of the bracket to mount the read head, and the cross slide is pretty much done, except for alignment. Hope to get that done tomorrow and also install the saddle scale and sensor.

[steamer]

oh oh oh!   watching along!   I'm waiting for my phone call for them to tell me it's delivered!!!!

 

[propforward]

Did yours not show up yet? I thought you ordered it a while ago?

[steamer]

Right after new years    They said they'd be expecting them in late February....and they would call me.

Dave

[propforward]

Oh got it, yes supply chain issues. That stinks but hopefully not long now!

[propforward]

Todays progress. There was some, even after enjoying some red wine last night. 

First of all, drilled and tapped the mounting block and did a test fit of the read head.



Happy with that. Also happy that when the time comes I will be able to fit the extruded aluminum shield over the set up. I'll need to trim the lower lip off and cut it to length of course, but the top of the cover sits slightly sub flush to the top of the cross slide so that the compound can rotate without interfering.



My kit has a 40" scale for the saddle, and I thought I would be able to just mount the whole thing in place without trimming, but I could not get the drill past the drive motor on the headstock end, so a couple of inches had to come off.



I then mounted it in place on the rear of the lathe using 1-2-3 blocks under the bed rails, and then transfer punched the drill locations.





That worked a treat for getting the mounting hole locations. I am planning on mounting the scale directly to the rear of the bed initially - I think I can shim the scale to get it flat along its length. If not, then I'll put a couple of spacers behind the scale, and mount the scale on a piece of stout aluminum bar instead,

For the mounting bracket, I made use of some of the bits in the install kit. This was longer than needed.



And customizing it is no problem of course.



The read head is mounted on a sliding bracket attached to the end of the modified mount bracket.







That is fine I guess, but it's not very elegant. I might either trim the lower bracket, or just make my own one. It just looks a bit clunky - not that you see it anyway - and frankly that may be the deciding factor. Once the install is finished and working I may just not see it and so it won't matter any more.

Speaking of working, having got this far I hooked up the readout temporarily to do a test.



It works! I wanted to do this in case there were any issues anywhere so I could address them, but looks OK. Everything is loose at the moment so I did not bother doing any accuracy tests, just turned the handles a bit and checked the numbers counted.

That's it for the DRO install for the time being - I'm not fine tuning the set up just yet, until I have performed the next upgrade. Sooooooooooo....................

[simplyloco]

I was anti DROs for many years, until i fitted one..

[propforward]

Voila!



I popped the lathe off of its stands using my engine hoist. No pictures of the process, because once I have the thing airborne I like to move it and set it down as quickly as possible. Don't need one of these moments:



Anyway, the next upgrade is to beef up the mounting of the lathe to the cabinets. The cabinet tops are about 3/16" thick steel, and it is very easy to deflect the cabinet top by leaning on the lathe - which can't be good  for keeping the bed straight in use. I can also feel the lathe oscillate gently as it runs.

So I had a couple of 1" thick steel plates waterjet cut at work, to place on top of the cabinets. I have sized the plates to be larger than the outside dimensions of the cabinets. In these pics I am just checking the holes line up.





Quick fit up of the chip tray.



While the tray is off, I intend to modify it. Some years ago I modified a brass bulkhead fitting to put in the tray corner, to return coolant to the reservoir. It worked, but it's a bit - I don't know - crap I suppose.





Now that I have some rudimentary welding skills I want to weld a barb fitting to that corner, and also cut a hole in the chip tray and weld a tube dam in place, for routing the coolant hose and the DRO cables through the tray and to the readout.

That's as far as I got. I now need to check how flat the plates are - I know they are not flat, but if they are really bad I'll have to fly cut them. Then I want to paint them, and of course mod the chip tray. Hoping to get that done in the evenings this week so that I can work on reassembly next weekend, and finesse the DRO install. While I am typing, here is a view of the saddle scale on the back of the lathe, since I can get a look at it now:



Pleased with it so far.

 

But now, it's time for some QI and 

[propforward]

I was anti DROs for many years, until i fitted one..

I know what you mean. I was doing OK without, but what the mill DRO has revealed to me in terms of backlash has been a game changer - my parts are just more accurate because that huge variation has been taken out - not to mention how much the table moves when I lock it, so having one has been really helpful. Hoping having one on the lathe will be similarly helpful.

[Craig DeShong]

Stuart

I’ve been thinking about a DRO for a while.  My lathe is a later model than yours (G4003G) but it looks pretty much the same.  You’ve done a good job of installing the scales where they are out of the way and your setup would probably work for my lathe also. 

I’ve gotta say that this post has certainly moved me further along the path of acquiring and setting up a DRO on my Grizzly.

For the most part, I use a dial indicator that clamps to the ways and measures the travel of the saddle.  This works well for measurements under an inch, but can be a pain for saddle travel over an inch.

You do have me rethinking.

[steamer]

I'm still on the waiting list for mid March delivery.....

Dave

[propforward]

Hi Craig,

I looked up your G4003G and it does look to be exactly the same lathe in terms of bed and saddle, basically it has a gearhead rather than belt drive and back gear, and the very nice addition of a camlock spindle (wish I had one of those), but otherwise I would think the DRO would fit the same way. These magnetic scales do make it very easy. I do know someone who successfully cut down some glass scales, so it can be done, but it takes a lot more care I think, and the lightweight cross slides on these lathes don't offer a lot of room. The magnetic read head fit in the available space well. I'm glad this post has provided some food for thought that way.

Dave - I sure hope your DRO shows up sooner rather than later! I know how keen you are to get that addition in place.

I was hoping to work more on the upgrades tonight - alas I have to do actual "work". Bah! Never mind, I have Friday off so that I can have a 3 day weekend and hopefully power through and get the lathe back on the cabinets.

[propforward]

A little progress today, although not as much as I hoped.

This piece of very nice sanitary tubing came home with me, fetched out of one of the scrap bins at work. It was a test piece for dialing in the orbital welder. I only need a small chunk to make a tunnel through my chip tray for the DRO cables and the coolant hose to go.



And this is where it is going. I tried using a hole saw to cut this out, but had to resort to cut off wheels. The Chinese steel in the chip tray was tougher than the Chinese hole saw.

 

There it is.



The hole in the lower corner is where the coolant drain goes. A stainless steel barbed fitting was supposed to arrive during the week but it is lost in the mail somewhere. So that has to wait a bit.



Well I did say that my welding skills are rudimentary. No matter, this will work fine.

Then a bit more set up on the long axis scale. It's much easier to get at while the lathe is off the bench, so I started getting it trued up. The spec is .004" flat over the full 40" length.

I started by clamping the scale down tight, and scanning a dial indicator across the whole length, noting the changes in height relative to a zero position. I chose the highest point of the scale as zero, which happens to be the headstock end. From that point on the scale dips down.







It's pretty easy to see that the clamping points are bowing the scale in, so the next step was simply to shim at the clamp points according to the measured bow. I had the scale within .015" very quickly.

My plan now is to get the clamp points flat within the .004", and then add shims at any other dip points as needed.

It is also necessary to get the rail parallel to the direction of travel within .004" over the 40" span. I actually had that right off the bat from setting it with the 1-2-3 blocks. I'm sure I'll need to tweak it after levelling, but that should not take long.

After that it will be time to get the lathe up on its new steel plates, once the chip tray is finished and the paint dry. I may see if I can find a stainless barbed fitting locally tomorrow. I'd like to get the chip tray painted during the week so I can set the lathe in place next weekend and start de twisting the bed and getting the headstock parallel again.

[Craig DeShong]

There is a lot to do to get this “right”.  You can’t just slap the scale on the back of the lathe bed and expect accurate measurements.

My Bridgeport mill came with an ancient DRO that started loosing segments in the display shortly after I received the mill.  I got tired of watching the DRO so I would know if the final number was a six or an eight (for instance) so a replacement was warranted.

Even with the “help” of a previous DRO setup, I spent multiple days installing the new DRO on the mill.  Looks like you are going to have an accurate set up when you finish.

An interesting side note: my mill came out of Cooper tools in  Apex, North Carolina and I have a friend who spent his career there in the tool room.  He tells his first task, when hired, was to install that original DRO on my mill.

[steamer]

It's nice to have the lathe off the bench for sure!!    That's going to be far more difficult for me as I don't have room to take mine off at the moment...gonna need to think about that very hard...I too will also have the 40 inch scale...

tell me about the "interstitial clamps" that appear to be a form of toe clamp?   Did you make those Prop?   Can you clamp on to the scale at points other than the ends?


Dave