G0602/G0752Z Compound Clamp

[WobblyHand]

Looking at the backlog of projects, decided to do this one next. This design is copied from @RJSakowski. Looks like:

With RJ's permission (a while ago) I posted the FreeCAD file in Downloads. So if you want the file, download it from there.

Started out with a piece of 1x4 A36 steel. Took awhile to whittle it down to the requisite 5/8" thickness.

Finally got it to the point of cutting the edges down. Used a roughing mill in two passes for the left side and got a little braver and tried a single pass to remove 0.115". Replaced the rougher with a finish carbide mill and did the last 0.010".

Put in the counter-bores with a 5/8" end mill. Drawing called for 0.600", but I had 0.625", close enough for this. I also drilled the bolt holes to M8 clearance, since I have M8 studs in the lathe now. Might as well do the other ones with M8 as well.

Got to the point of doing the central hole. Err, how am I going to do that. Remembered I had a few hole saws and picked out a 2" hole saw. Set it up in the mill and turned it on slowly. Holy cow, talk about run out! About 1/8" run out. Fortunately the required hole is a bit larger, so decided to still use it. Used a ton of cutting oil and had to clear out the swarf a lot. Eventually punched all the way through.

To enlarge the hole I was going to use the boring head on the mill. I set everything up and stared at the hole. Arggh, something isn't centered. Did a clean up pass on the boring head and decided to take it off the mill for figuring out what went wrong. Have to confirm this, but it seems to be off by about 1mm in X. I don't know how this happened, I used the 1/2 function in the DRO when setting up the piece.

Anyways, I cleaned it up and deburred stuff. It fits fine on the lathe so far. I just think the main hole is off center in X. Will reindicate it and bore out the hole. It is currently at about 53mm, and needs to be 70.38mm in diameter. So there is enough wiggle room to fix it.

 

[WobblyHand]

Re-indicated and had to bore an off-center hole to recenter. Pretty much already pushing the envelope on the mill, but with a bit of patience got it done.

Did a fit check of the protractor wheel with the bore and it was ok, neither too tight, nor too sloppy.

Got it to fit on the lathe. Was a little tight in the first orientation, but rotated the clamp 180 degrees and fit like I meant it. Miracles do happen.

Tomorrow I need to make the big counter-bore 84.1mm on the bottom side to fit the wide part of the protractor wheel, and to cut out the view port so the protractor is visible. Probably use the rotary table to do the view port.

Made some decent progress today.

 

[WobblyHand]

Bored out the 84mm section for the protractor wheel. Ran the mill in reverse so I could use the boring bit pointing radially. Came out better than I expected.

Test fit everything again, to mark where the cut out will go. Everything moves smoothly without binding, including connecting the protractor wheel.

Need to break for lunch and clean up the mess for the next set up. Need to make room on the mill!

First use of the rotary table for something. Since I have little idea what I am doing, it will be interesting... Thinking of making a locating mandrel to get it centered. My fixture plate has a 32mm hole in the center. Might use the protractor wheel as part of the mandrel, then I won't need large diameter stock.

 

[rabler]

Looking good. Glad to see that lathe is getting the deluxe treatment

 

[WobblyHand]

Hmm, my idea to locate the plate on the rotary table is ok, but unfortunately, the protractor wheel is in the way of machining! I made a mandrel, more of a pin out of 1144 that was 30mm to fit in the plate, and 20mm to fit the hole in the protractor. Unfortunately, can't use this during machining, but it is handy to line everything up. Have to say, I love machining 1144. It parts beautifully too. Had no problem parting 1-1/4" stock, right down to 1/16" nub.

Of course, I could only get one hole to line up, so I need to drill a bunch of holes. Not a problem, but need to make or get a bottoming tap. The rotary table is lined up and zeroed, as is the fixture plate, I don't want to set that up again. It is hot in the shop, and it sort of drained me. Got tired and had to come up and rethink things. Undoubtedly, there's an easier way to do this, but being tired makes it hard to see... Hopefully tomorrow will bring all sorts of ideas.

 

[GunsOfNavarone]

I was so thankful to have my CNC mill. I modeled it up in F360 and let my mill deal with tool steel I used. A lot more bolts to fiddle with, but anything for more rigidity. Cheers to @RJSakowski !!

 

[RJSakowski]

I was so thankful to have my CNC mill. I modeled it up in F360 and let my mill deal with tool steel I used. A lot more bolts to fiddle with, but anything for more rigidity. Cheers to @RJSakowski !!

The CNC mill is the way to go.

While you are doing this, add the three extra M6 x 12mm screws for the graduated dial. That mounting is now the weak link and the three additional screws will greatly enhance the rigidity of the compound.

 

[GunsOfNavarone]

It's long finished, but I'm lost as to where you're talking about adding the M6 x 12 screws?

 

[WobblyHand]

The CNC mill is the way to go.

While you are doing this, add the three extra M6 x 12mm screws for the graduated dial. That mounting is now the weak link and the three additional screws will greatly enhance the rigidity of the compound.

So 6 M6 screws? There are 3 M6 screws now. Not hard to do, but why not up size the existing M6 to M8?

 

[RJSakowski]

It's long finished, but I'm lost as to where you're talking about adding the M6 x 12 screws?

It's long finished, but I'm lost as to where you're talking about adding the M6 x 12 screws?

The compound clamp locks down the graduated dial which is mounted to the compound body. IMO, the three M6 screws are nit adequate to prevent flexing so I doubled down on them. P/N's PCAP26M and P0602205.