Home-Made Circle-Jig for my Plasma Cutter

[tomrscott]

jimgerken,

With respect to the holes. I get your point (no pun intended).

I was talking with a guy at work that spent many years as a tool and die maker, and we were trying to figure out the best approach. His experience was that every time he tried to hold more precision than experience told him was reasonable, his experience won out. In principle I agree, but at the same time I can't help but want to get these to be as snug as I can make them. I can always open up the holes if I absolutely must, but I want to try to get them as identical as possible.

What surprised me about the comments of my tool and die friend was his belief that a 1/2" drill would not remain straight for a two or three inch stack of plates. I confess this really does surprise me. I would have thought that once I got the first plate drilled well, the remaining stack would be very well aligned if I had them well clamped together.

I really hate to drill 168 holes one at a time, not to mention doing them in steps too.

The trouble is, if you have to drill a pilot hole through each plate before drilling the larger hole, you almost have to do each one separately, because you can't count on a 1/8" drill running true through more than one or two at a time. That's where I thought using a 1/2" drill through a stack would be an advantage because the 1/2" drill is so stiff. I guess I realize that a pilot drill will keep a larger drill from wandering, but if you have a 3/8" template plate to keep it centered, I would think it would drill just fine.

I may have to do some experiments to see what works best. I'll let you know what I end up doing and how it works out, but I am "into" making it as simple and efficient as I can. Never enough time.
/forums/images/graemlins/smirk.gif

 

[PineRidge]

If it were me I would modify the design and burn not drill one larger hole through the center of each plate. Use a knockoff like used on some of the old racing wheels to hold them in place eliminating yourself a lot of unnecessary time and work.

 

[slydog]

I'd think it would be kind of tough to hold up all that weight while trying to keep the carraige bolts secured in the holes through the rim untill I got all my weights on. My thoughts are to bolt a single plate securely to the rim, and weld several case hardened bolts through the holes in the first plate, for your "mounting bolts". Making that first one my mounting plate. You might have a little gap between this one and the first weight plate, but at least it would be secure to the rim, and the weight bolts wouldn't wobble while you were trying to add more weights and bolt them all together. Just a thought.

 

[PineRidge]

Ken with a floor jack it isn't bad at all. adding weight

 

[slydog]

Great idea Mike. Man...you guys are so resourceful.

 

[tomrscott]

Just another update on the wheel weights for those who've been following this.

I admit this is a lot of work for wheel weights, but 900 pounds of weights would cost quite a bit, and not counting the plasma cutter and incidentals like paint and carriage bolts, these are going to be essentially free. I could easily sell the plasma cutter for more than I've got in it, but I think I'll keep it instead. /forums/images/graemlins/smirk.gif

Anyway, there are a lot of surface weld beads to grind off so that the plates will lay flat. (Remember I was gouging the welds off of some angle brackets welded to the plate. That leaves about half a weld bead of crud to be cleaned up later.)Almost every plate has a couple inches of welds somewhere. A few have a lot more than that. I am going to take the worst offenders and use them for the bottom plates where I'm going to weld on some scraps and run some filler beads both to get some practice welding, and to fill in the space around the wheel lug bolts.

I've got over half the plates cleaned up as of today. I finished knocking the slag off the back sides with a chipping hammer on all 42 plates today, then I ground the edges and surface crud off of about half of them, and sanded them with a rotary disk sander to remove loose paint, rust, and crud, and then sprayed those with rust-preventive primer.

I'm also cleaning up the edges in places where I didn't get a clean cut due to my errors or a nozzle that was getting bad. I started doing the surface grinding with a die grinder, and a small wheel, and that works real well, lots of control, but it just takes too long. I finally took the safety shroud off of one end of my benchgrinder so that I could hold a disk face against the grinding wheel underneath or on the back side, or wherever was most convenient. That works much faster! I can clean up even a disk with a lot of surface welds in just a few minutes. It does get a bit tiring holding 21 pound plates up and guiding them past the grinding wheel to remove the surface welds.

A couple more days of work and I should be able to get them finish painted and mounted. It will be real nice to have enough traction to grade my hill. /forums/images/graemlins/smirk.gif