8x30 Milling Machine Restoration

[AndySomogyi]

Thanks for the info.

I was thinking about just lifting it out by hand, looks like it probably only weighs about 100 lbs or so (I deadlift 300 ), but maybe a hoist is smarter, like the hook idea.

It almost looks like with the gib removed it might slide straight out.

I originally just planed on scraping the top ways on mine because they were damaged from previous owner, but I’ve now found out that the knee is tilted sideways by about 0.015 over 8”, no wonder I could never machine a square part with that knee.

Got a thread of my disaster here:

Grizzly G0678 8x30: Repair, Scraping and Alignment

to be honest so far I've been pretty impressed - the nod was out by a touch, so I sorted that out with a piece of 7-up can between the knuckle and the base, which put it within 0.01mm over the width of the table. All the sliding surfaces are in good condition, no gouges or ugly machining marks...

www.hobby-machinist.com

 

[Mtnmac]

I bought one a couple years ago. Found it down the road at a estate sale, 400 bucks. I put my DRO on the front of the table too. I made extensions so the X axis table locks extend out beyond the scale cover. It's been a good machine, but will get a VFD eventually and keep the ability to move the belt for low end torque. This also will give me reverse spindle rotation... this machine has none.

 

[Radials]

Thanks for the info.

I was thinking about just lifting it out by hand, looks like it probably only weighs about 100 lbs or so (I deadlift 300 ), but maybe a hoist is smarter, like the hook idea.

I actually weighed my knee while it was out. Only 55 lbs.

 

[AndySomogyi]

I actually weighed my knee while it was out. Only 55 lbs.

View attachment 339616

Thanks Much.

I got mine out, I’m surprised at how light it is. The bearing to screw fit was a bit on the tight side, but I just screws the Z screw in and it came loose.

Now I’m working on squaring it up. The dovetails are WAY off, like 0.015 over 8”, and top ways were ground with a 0.005 twist. I’m guessing the knee probably slipped when they were grinding it.

 

[Radials]

Ok, finally got a power feed on my mill. A few more details to sort out but came out nicely.

Here's the project thread.

8x30 Power X-Axis Power Feed

I've had an 8x30 x-axis power feed modification on the back burner for quite sometime now and I'm getting close with the project being complete. A goal of this project was to also replace the leadscrew bearing blocks on either end and align the leadscrew which was not parallel to the table. The...

www.hobby-machinist.com

 

[Pfowler67]

Hi everyone. Excited to see some further modifications to you mill there, Radials. I just received my Sino DRO so am keen to get into that next, but here’s some pictures after getting mine home and into place.

 

[Pfowler67]

I still have some dialling in to do before the DRO goes on, so will do that first. There are some other mods I’d like to make too. One concerns the x axis leadscrew arrangement. Seems to have been put together rather wonkily! Doesn’t seem right anyway. I’ll put some pics on here for you to see.
Keep up the great work, Radials and everyone else!

 

[Radials]

I still have some dialling in to do before the DRO goes on, so will do that first. There are some other mods I’d like to make too. One concerns the x axis leadscrew arrangement. Seems to have been put together rather wonkily! Doesn’t seem right anyway. I’ll put some pics on here for you to see.
Keep up the great work, Radials and everyone else!

Yea, as mentioned on my X-Axis power feed mod thread I also had a wonky factory install job on mine. The time I spent laying out the new bearing blocks to correctly align the lead screw made a big different in the feel of the mill.

 

[Pfowler67]

Hi folk!

So I finally got around to getting the new mill up and running, dialling in the gibs and have almost completed the DRO install. Here's some pics of the work so far. I will do the Z axis scale tomorrow.

I'm really happy with how rigid and well the whole thing has gone together so far. The trickiest part so far being the X axis reader mount, which I have made a special bracket for. I chose to mount the X axis scale on the rear of the table, as I like to use the limit stops on the front of my current machine and have managed to keep the amount of lost Y axis travel down to a minimum. The new machine has way more travel than my old machine so i'm happy to live with this decision.

I will post details on the Z axis installation soon.

 

[u50067]

Yes there are two bearings on the knee lead screw. I removed my knee by rotating the head out of the way and cranked the knee up as high as it would go. With an engine hoist attached I loosened the knee gib and then hoisted the knee off the dovetail with the screw still attached. This method worked but the knee wasn't balanced and was finicky to handle once in the air. My picture below indicate I changed the sling method at one point during removal.
View attachment 339371View attachment 339372
When I put it back on I made a block to mount to the center of the knee dovetail and got the balance right before lifting the knee up in the air so it was easier to guide back onto the base.
View attachment 339373View attachment 339374
The bearings as I recall didn't need to be pressed out, but tapped out with a brass punch. There is a castle nut and (tabbed washer?) that hold the screw into the bearings that is easy to remove.
View attachment 339375


-Nick

Am a new member. I have a Jet JVM-830 mfg in 1978. Have used it mostly for drilling holes on location. Have found the knee to quill distance to be not quite enough a couple of times. So am considering making a riser. Would like to fab the rise before disassembling the mill for installation. I need the female and male diameters of the interface between the head and column. Also the depth of the female diameter that the male diameter is inserted into