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This might not sound like much of a project from the title but it was much more involved than you might think once you see it. There was more machining than welding but I couldnt have made it without my handy Lincoln 225. I dont claim to be a welder but I get by.My brother picked up a welding positioner from his employer for free that was over 25 yrs old and had a real nice 15 Buck 3-jaw chuck that I figured I could use on my 20 lathe. The positioner had hardly ever been used and the chuck was in excellent condition. I took off the Buck chuck, installed an old 10 4-jaw chuck on the positioner and sold it. The removable reversible jaws on the Buck chuck had been modified and were unusable with a lathe. While researching the chuck looking for a set of jaws, I found that Buck still sells the exact same model chuck but it is imported. My chuck was American made before Buck began importing their 15 chucks. It is one of the "good ones". I also found that Buck makes replacement jaws for this chuck so I bought a set.With the jaw problem solved, now I only had to make the back plate. I had a 1-1/4 x 14 diameter piece of steel plate which I welded a 5 diameter x 3 long piece of steel bar stock. My lathe spindle is 3-1/4-4 which I machined the back plate to fit. The O.D. of the back plate was finished at 11.780 and fit into the back of the chuck. There are six 5/8-11 socket head cap screws to secure the back plate that were drilled and tapped. This chuck weighs 221 lbs alone, with the back plate over 260 lbs. It turned out really well. Attached Images
Reply:A few more pics. I know everyone likes to see pics. Attached Images
Reply:Oops, I put it in the wrong category. It should be in projects. Maybe an administrator can move it.
Reply:I can't really see the weld well or how much you machined off, but I'd be a bit concerned with all that mass spinning on what little I can see. The reinforcement on a fillet weld is quite important. Machining off a good bit will weaken the weld. Add to that all the hollows and undercut I see in the finished product, and I wouldn't be real comfortable. All the welds I've seen machined down are usually done oversized so that after final machining they still have enough "meat" to them. Also I often see a groove or bevel machined into the original materials below the face, that then gets filled past flush so most of the weld is not touched in the machining operation.All those craters and hollows are places cracks can start. If the weld is very thin there because of the machining, then you've got a ready made place for the weld to start unzippering. If that hapens at high rpm, you're in for an interesting afternoon. Hope you stock a spare pair of shorts! .No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I appreciate your concerns. My welds may not be the prettiest but I am not the least bit worried about the integrity of that weld. There is plenty of penetration and even after machining, there is still plenty of weld left. This chuck will spin at a max of 78 rpms. |
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发表于 2021-8-31 22:30:51