Stretching the Boundaries Yet Again (Surface Grinding Shapeoko)


(Richard Cournoyer) #1

Here is a hardened steel (Rc 65) Toolmaker’s Vise that I finished Ground on my Shapeoko:

Note: ALL surfaces are ground square, parallel, etc. (My tolerance was +/- 0.00025")

Check out my IG for lots more photos and videos (JPL_Richard)



If you’re interested in the story, continue reading:

About 30+ years ago, I was given an unfinished 752 Vise Body. It was pre-machined, heat treated and tempered to 65 Rc. Missing was the jaws, lead screw (of a proprietary thread pitch), and the jaw retainer. When I was working in a machine shop I could never find enough (personal) time to work on this vise, so it sat.

Along came the Shapeoko 3 and while I knew I could make the missing jaw parts, the lack of a lathe and grinder kept this project out of reach. One day @ApolloCrowe (you remember that guy?) told me about a Tool Swap meet. At the show, I found a thread gauge and found out the proprietary thread was actually a 32TPI…and THIS moment was the starting point.

If I could make the lead screw, maybe I could tackle the rest of the parts…even the grinding (on the Shapeoko). I determined that the thread OD was somewhere between 5/16 and 9/32. I bought a 5/16-32 adjustable die and practiced. on some soft steel. When I finally figured how to make the correct size, I then I purchased some grade 8 bolts (to use as bar stock). I annealed them to a soft state and then threaded two of them, and kept the best one. I then re-heat treated it and tempered the lead screw to 40-45 Rc (Rockwell C Scale)
Using an old index tool I made last year, I used it to mill a straight knurl on the lead screw as will install a ball plunger to add tension to the dowel pin handle.

Now I was ready to tackle the vise!! I have seen far too many toolmakers who have lost one or the other jaw, I also decided to forgo the two piece jaw design of a single jaw (longer that the short jaw, but shorter than the stand long jaw. I purchased a foot of O1 tool steel, and using my power hack saw (another Shapeoko project) I lobbed of a piece. I decided that 0.010” extra material all around was enough to allow for grind, so I designed the finish part in Fusion360, then scaled the part to 101.14 percent.

Once the jaw was finished machined I made a redneck Heat Treat Oven out of a few fire bricks. Heated the material to 850ºC (1560ºF) I then tempered it at 400ºF to Rc 62-65

Grinding: I purchased some 6mm shank Grinding wheels (40mm Dia x 10mm Thk) Grit unknown, but I guesstimate 36 grit. $1.30 each.

I set up two diamond wheel dressers. One to dress the OD and one to dress and dish the bottom

Setting I picked:

Speed: 12,000rpm
Feed 11 to 20 inches a minute (travel)
Down feed between strokes 1mm
Depth of cut: 0.002” (max)

Commerically available B&S Vise: (Note the new corner relief for the jaw)

My Vise (Ground to within 0.0003") Ealier designs never had a corner relief, they (and mine) were ground square)


(Dan Nelson) #2

I tried to like this post 3 times, but the best I can do is one like and one “AMAZING WORK RICH!!!”

Heat treatment oven from some fire bricks a torch and a thermocouple? Where do you get these ideas???

Dan


(Richard Cournoyer) #3

Thanks, this machine continues to impress even me!

Well, as an old guy, I was taught to heat treat using a just color chart to determine temperature (and just fire bricks), so adding a thermocouple is a BIG step up for me. PS Once the oil is washed off, the kitchen oven (with a thermocouple) is a great place to temper metal…when the WIFE is away…


(Phil Gorsuch) #4

So much awesomeness to take in here. Curious how you set up the toolpath for the knurling using the index tool. Did you have to rerun a single gCode file each time you moved the index or is there something more clever at play there?


(Richard Cournoyer) #5

Nothing crafty or fun about a manual index head (homemade or purchased) it’s run the program, index, repeat. Now if GRBL and @Jorge can sell a 4th axis…then I’ll make that thing dance (I promise).


(Phil Gorsuch) #6

Would be keep to see that! Was just idly pondering if it would be faster to do something like a loop with a tool change (in which the tool isn’t changed - just a way of pausing) than run the program again and again.


(Richard Cournoyer) #7

Loops and pauses are easy to program, but for me, it is a safety concern, since I need to manually index the well, indexer with my big fingers, and with a mild case of ADD, I am seldom doing one thing at a time…

I SOOOOO want a 4th axis…even if it is just an indexer and not capable of simultaneously machining…


(Phil Gorsuch) #8

Must be imagination day for me. Mechanical or electromechanical advancing indexer that gets advanced by a carriage move to the far end of the X axis or some such?


(Jerry Gray) #9

I believe there would be a real market for these. I can’t find anything under 4".
And if it wasn’t for the warranty, I was thinking one could add connectors to thier Y motor leads so they could swap the leads (one of them, the other idle i suppose), and reconnect the lead to a rotary axis.
All the Y moves would be on the rotary table, like a 4th axis.


(William Adams) #10

Well there’s this:

and

(similar thing drawn up here recently)