Toolpost Grinder For Sb9a

Hi All,

When I purchased my lathe, it came with a Union Manufacturing 6" 3 jaw chuck. This chuck uses two piece jaws, but no jaws were to be found in the shop where I purchased it from. I did find replacement jaws from Shars, but their QC must be asleep on the job. There is one problem child jaw that throws about .006" runout to the workpiece being chucked. The runout follows that jaw, so I know it's the wonky one. I need to grind my chuck jaws.

Since my knockoff Dremel isn't well suited for this, and because my hobby funds are flat broke, I decided to see what I could cobble together from the scrap bins. I laid my raw materials out, stared at them for a bit, then tossed a few ideas into the back of my head and let them stew. The next evening, I doodled a few lines in my project notebook and got started.

The spindle is 3/4" CRS, about 5" long. I have a suitable piece of steel bar to make the housing from. Bearings and motors I have in plenty, so no problem there. I decided to copy the spindle of my RotoZip, because I have collets and an extra collet nut for it on-hand. It can take up to 1/4" shanked tools, so it'll be useful. I've had no issues with runout on the rotozip.

I started by cutting a piece of 3/4" CRS about 5" long. Grabbed it in the 4 jaw, indicated it, then faced and center drilled it. Flip the workpiece and repeat.

Off with the 4 jaw, on with the dog drive plate. Installed the dead and live centers, slapped a dog on the workpiece, and got it mounted.


I hogged off most of the material with a tangential tool, and got close to the desired diameter for the spindle shank. Ran out of time, and the workpiece needed to cool anyway.


More to follow as the project progresses.

Been doing some more work on this project. The spindle is finished, threaded 1/2x28 for the Rotozip collet nut, bored for the collet, and the bearings are a 'little bit of hand effort' slip fit on the shaft.



I worked on the housing. Got a handful of these cylinders from a friend, and aside from the fact that they're hard as heck, they cut nicely with a really sharp HSS tool. It's actually easier to face off 1/4" than to cut it off with a sawzall.

Grabbed it in the 4 jaw, dialed it in reasonably straight. I knew the entire diameter would be reduced, so I didn't chase zeroes on the DI.


I love my tangential tool. Easy to sharpen, cuts facing and turning without moving it, and it can flat hog off some material. Even on this stuff. If it gets dull, it takes no time at all to re-sharpen, and it's easy to set on center.



A quick hit with some sandpaper, and it shines right up.



The bore came out nicely. I'll have to heat this in the oven for a bit so I can press in the bearings. Getting them out would promise to be a pain, though.

I still have to turn the end that's currently in the chuck, face it, and bore for the rear bearing. I decided to use two bearings in the front with a thin spacer between, just because I can. I figure two bearings can take a beating better than one bearing, and it supports more of the spindle shaft than a single bearing. It's been nice to get into the shop and concentrate on just making chips.

Way to go! I'll be watching this one closely. Great start.

"Billy G"

Made some soft jaw pads for the 4 jaw chuck. Simply cut some 1" copper pipe pieces about 1 1/4" long, slit them lengthwise, and spread them open just enough to fit over the jaws on the chuck. Reversed the workpiece, dialed it in with a DTI and spent the time chasing the zeroes on this one.

Got the rest of the housing turned, and faced it to length. Now I'm waiting for it to cool before I bore the recess for the rear bearing.

Once the bearing recess is done, I'll move to the horizontal mill. My plan is to cut two areas away above and below the centerline, along the axis of the spindle, so as to leave a 'tab' sticking out which can be grabbed in a toolholder for the QCTP. I'm still contemplating what motor to use, and how to mount it.

But one thing leaves me at a loss. The Atlas horizontal mill has V grooves that run the length of the table for clamping round stock. However, I'd rather not mar up the finish of the part too badly on the cast iron table. I can use copper pads underneath the clamps, but I'm not sure how to pad the V groove in the table. Should I use a piece of soda can (aluminum) between the table and the stock? Would that still let it register good in the groove, but protect the finish? I've got a decent amount of time into this workpiece, so I'd really rather not mess it up. And after cutting away the metal to form the tab, trying to polish it in the lathe won't really be a smart thing to go.

Pics to come this evening.

Work was paused on account of lightning. I don't relish the idea of being in a big tin can with lightning hitting all around. Nope. After the weather calmed down, I wandered back out to the shop and kept on working.

Housing turned to length, and the rear bearing bore is done.


The setup to mill this. The vertical mill is great for this work, but the angles make it hard to see what you're doing. I found the top of the workpiece, and used an indicator to set the height and my noga-knockoff to watch the depth as I made repeated passes. The tab ended up being just enough for a QCTP holder to grab securely.



The tab is done, and the part cleaned up. Tomorrow if I have time I'll figure how to mount a motor on it, and do any last machining that has to be done.



CHIPS!








More to come.

Nice work !!

Very nice work!

Looking good!

very nice work. anxious to see how you mount the motor on there. on a side note, i also love my tangential tool holder, you can really hog some material off. that thing does 90% of my turning.

I'm in the process of making a new spindle, longer so I have more reach and more options for mounting a motor and pulley on it. Taking video of it, and will post a link to it once I have it ready.
Also going to make an arbor so I can utilise my 3" grinding wheels. It's an interesting project, and easier than I thought it would be.

Love the tangential tool. It's my go-to tool for turning and facing. Only 1 angle to grind, so touchups are literally about 2 minutes, and that's from taking the toolholder off the qctp, to making another cut.

The vertical shear tool is another go-to tool. Again, easy to sharpen, superb surface finish even on 1018 crs. Slow, and not for hogging, but leaves a buttery smooth surface.

Stay tuned, should have lots of shop time this weekend.