My New Grizzly G0678 Knee Mill

[wallyw]

Since it turned out to be a relatively easy job, I installed the limit switch for the mill today so the feed install is now complete.

After removing the center limit block from the table, I took the factory switch plate and made it flat, cut some of the top off and then drilled and tapped new holes for the switch box.

View attachment 116511

The feed kit has spring-loaded stops to protect the switch box from over-travel but they are large and unnecessary with this small mill. In the picture I ran the table into the limit switch at full balls-out speed and there is still travel in the switch. Also, the table has overtravel stops that work against the knee so if you set the adjustable limit stops correctly, when the switch bottoms-out the table overtravel stop will help save the switch box.

Actually got to make some chips with the mill today and I really enjoyed having the power feed. It's a labor saver and a really nice upgrade.

Very nicely done!

Wally

 

[coolidge]

I put the limit switch stuff on mine.... But i think I'm gonna take it off. I have to put the Dro scale there.... don't wanna loose the room in the back.

where do u plan to put your scale?

I'm mounting my X scale on the front to avoid losing Y travel, plus I retained use of the limit switch and table stops. Its not my intention to hijack the OP's thread here, but just to give you guys some ideas since I'm in the middle of this install.

In this pic I have mounted my scale to some 2.5 inch x .5 inch aluminum bar, turned a couple of brass spacers on my lathe, and ordered some stainless T nuts for the front of the table from McMastercarr.



Here you see how I have mounted the scale forward from the front of the table with the brass spacers, providing room for the limit switch and table stops.



Here is the first part of the bracket for the scale read head, this bolts on over the top of the limit switch using the same holes.



Here you see the bracket bolted in place, this brings me out just beyond the surface of the scale. Next I'll make a bracket that goes up, allowing adjustment up/down, then a bracket that the read head will bolt to that will adjust in/out and I'm done. Note I had to machine a channel in the bottom of this bracket for the limit switch cable. Anyway again just giving you guys some ideas.

 

[coolidge]

Doogie if you like the X power feed consider power feeds for Y and Z. I installed all three and love it. The Z power feed is slow enough that you can adjust Z as slow as .001 per second. Except for drilling or plunge hogging I have locked my quill into place and use the Z power feed to adjust depth as I'm machining.

 

[DoogieB]

That's a great install, Coolidge! I'm always looking for clear pictures of scale installs for ideas.

 

[coolidge]

I wrapped up the X scale read head brackets this weekend, I machined the back side of the bracket to get it close then shimmed .025 to get the proper clearance between the read head and the scale, the kit includes a plastic .017 strip you put between the read head and scale to adjust to the right clearance then pull out the strip.

So this bracket adjusts in/out via shims which required some accurate measuring and machining but this kept the bracket compact and tight. I had intended to make a three piece bracket where the top piece would adjust in/out via a slotted channel but I found that would have stuck out quite a bit farther.

Again this is just to give you guys some ideas on a front X scale install vs a rear.

 

[wallyw]

I wrapped up the X scale read head brackets this weekend, I machined the back side of the bracket to get it close then shimmed .025 to get the proper clearance between the read head and the scale, the kit includes a plastic .017 strip you put between the read head and scale to adjust to the right clearance then pull out the strip.

So this bracket adjusts in/out via shims which required some accurate measuring and machining but this kept the bracket compact and tight. I had intended to make a three piece bracket where the top piece would adjust in/out via a slotted channel but I found that would have stuck out quite a bit farther.

Again this is just to give you guys some ideas on a front X scale install vs a rear.

Very well done! I'm finishing up my Y axis. Only left with X. Looking at your beautiful install I may rethink mounting to the front.

BTW can you describe and name your power Z?

Wally

 

[coolidge]

All three of my power feeds are Align brand purchased at Enco.

 

[DoogieB]

Hey Coolidge, from where did you buy your DRO?

 

[DoogieB]

Just wanted to post a picture of the G0678 mill using a slitting saw. It wouldn't have hurt to run the blade a bit slower, but I just wanted to show the mill working fine under a light load at a relatively slow speed. The VFD really works well on this machine. It's so nice to just dial-in the speed you need without moving belts or shifting gears. Spot the hole at one speed, drill at another and change it again to de-burr with a reamer. Sweet.



There's no screaming cooling fan on the VFD either. Apparently the cast column functions pretty well as a heat sink, although I have yet to pull the panel and take a peek back in there.

 

[DoogieB]

It's been awhile since I posted anything on the G0678 mill as I've just been using it for various projects. I just did a small mod/upgrade and thought that it might be interesting for other mill owners so here it is.

I like using stops for repetitive operations and one on the quill can come in very handy. Unfortunately, like most mills and drill presses the stop is just a knurled nut and it can take quite a few twists to get it into position. Quick adjusting nuts are available, but almost all of them are for SAE threads and all the threads on this mill are metric. The project is to make a new threaded rod for a quick-adjust stop nut. It's a simple single-point threading job on the lathe and they are always fun.

During the last big Enco sale I bought a Morton Quick adjust quill stop (#1220-S).

http://workholdingcomponents.mortonmachine.com/viewitems/workholding-components-nuts/quill-stops-1?

It's nicely manufactured and made in the USA. This stop is for 1/2-20 threads.



Here we are trying the stop on the freshly-turned 1/2-20 threads. You push a button in on the side of the stop to slide it up and down the threads. When you release the button, it snaps into the threads and you can turn the stop normally using the markings for further positioning.



The mill is getting into the action by cutting a screw slot into the bottom of the newly threaded rod. Also got to use my brand new collet block and ER collets. Sweet!

The bottom of the rod is screwed into the head casting. The threads in the casting were, thankfully, a really coarse SAE thread, I think 11 TPI.



And now it's all together, with the stop in the parked position the whole way down at the bottom. I used blueing on the threaded rod for some corrosion protection and to match the rest of the hardware.



The stop is now pushed up against the quill dog. It works perfectly and it looks nice.