Black Frog Posted May 17, 2013 Share Posted May 17, 2013 Center of my pritchel to center of hardy is 3-11/16", so that makes for a fairly large rotating bolster plate. I have a 10"x10" sqaure 1/2" steel plate I could use for this. I would cut the corners to make an octogon. I thought this might be a chance to incorporate round and square holes all on the same plate. One half of the plate's holes would be drilled slightly undersized, and then drifted square to shape/size. What I wanted to do is leave enought "meat" between the holes so that when drifting the squares it doesn't effect the hole next to it. I slightly increased the meat between the holes as the hole diameters increase. The largest hole is 1", and there is roughly 1" of material all around that hole. I went in 1/16" increments for the diameters of smaller holes, and then bigger increments as the diameters get larger. I figured the smaller holes might be used for finer work and proper support would be more useful than some of the bigger diameters I left off (like 5/8", 7/8"). Does this look like a good idea before I go any further? Recommend any changes? Quote Link to comment Share on other sites More sharing options...
Chinobi Posted May 17, 2013 Share Posted May 17, 2013 maybe some kind of spoke or handle to facilitate spinning, and a way to lock it down once you have it in position. make sure you pay attention as well to the orientation of the square holes relative to the hardie hole, IE don't line your largest square up to be radial from the center point if the hardie and pritchel are not actually in line with each other. Quote Link to comment Share on other sites More sharing options...
Black Frog Posted May 17, 2013 Author Share Posted May 17, 2013 I thought about that sqaure orientation relative to the hardy as well. That will have to be implemented (and remembered!) when the square holes are drifted on the anvil. As far as a handle, I didn't want anything sticking up above the surface of the plate. Having a flat bolster plate gives more flexibility (to me) for holding/placing odd shaped objects for drifting, also positional stance at the anvil depending on the shape of the item to be drifted. I'll be using a countersunk bolt for the middle center pin that will provide for a flat surface. Maybe add three or four 1" "finger holes" in the middle area for easier lifting and removal of the plate? A lot of the plate will be hanging off the end of the anvil, so removal shouldn't be too tough. If a position lock down is needed, a quick/dirty method would be to clamp in place on the heel with: Quote Link to comment Share on other sites More sharing options...
Chinobi Posted May 17, 2013 Share Posted May 17, 2013 im having zero luck with forum search results today(I was going to recommend a tusk and tenon design I saw another member employ for a hardie mounted hold down, but I dunno how well that will work in the pritchel) :( you could put a fat washer and a nut on the bolt you are using as the axle to lock it down, weld a big grippy shape to the nut so you can quickly hand tighten and loosen as needed. im not a big fan of those types of clamps on sloped surfaces (underside of the heel) especially under vibratory loading, pretty good potential to slip. something like actually bolting the plate to the anvil will prevent it from lifting and bouncing, but a secondary pin of some sort to prevent rotation would really make it one with the anvil. Quote Link to comment Share on other sites More sharing options...
Black Frog Posted May 17, 2013 Author Share Posted May 17, 2013 This is the anvil I'll be using this on, I could make a wedge-shaped washer piece so that a large lock-down hand knob will tighten flat on the underside. Quote Link to comment Share on other sites More sharing options...
Chinobi Posted May 17, 2013 Share Posted May 17, 2013 yup that will keep the nut from trying to rack and bending the bolt or wrecking the threads. Quote Link to comment Share on other sites More sharing options...
Jim Coke Posted May 17, 2013 Share Posted May 17, 2013 Greetings Frog, Unless you are punching plate on the bolster you could just put a bolt from the underside with a welded wing nut on top... or a swing lever on a bolt top with the nut on the bottom... Both could be moved for normal bar punching... I hop this helps.... Good ol Jim Quote Link to comment Share on other sites More sharing options...
John B Posted May 17, 2013 Share Posted May 17, 2013 No need for a hold down, if mine was anything to go byThe purpose of the bolster plate is to back up to the hole size as you punch through, punching is first done on the anvil, and you will not be punching a 1/4" hole through on a 1/4" hole in the plate, you need clearance and have to position work over the appropriate hole,With regards to handles, again in practice the centre fixing is a loose fit in the pritchel hole, and the plate will spin freely on the anvil's face, you can use the punch as a handle to turn it, or just turn by hand.Keep it simple and don't over engineer it, this is another case of where less is moreIt may be more useful to consider making a saddle of the same thickness as the plate to fit over the other end of the anvil as a spacer to align/level longer pieces when they are being finished punched/drifted. Quote Link to comment Share on other sites More sharing options...
Quarry Dog Posted May 18, 2013 Share Posted May 18, 2013 You could just drill a hole in the middle the size of the pritchel hole and use one of those springy pritchel hold-downs to keep it centered and to keep your work clamped down. This would also allow you to punch holes up to the size of your hardie hole. You could even do a punch in the middle of a big scroll by dropping the hold down in the middle of the bolster after the scroll is already resting on top of it. I might taper the end of the hold-down though, so that it's easier to get it into and line up the pritchel/bolster combination. The only issue I can see is if you're trying to punch a hole in the middle of a piece of plate, and even then just leave the hold-down out of the equation. If i recall correctly, punching a hole in any isolated area (such as the middle of a plate) causes unsightly warping due to the upsetting around the hole. Because of this I can't imagine too many situations where you wouldn't be better served by either drilling a hole or just torching it out and filing for finish. Also, for the smaller square-drifted holes you may want to try drilling a larger sized hole from the back about halfway through, that way your smaller drifts don't get stuck and the material has somewhere to go beside where it will cause warping. Something else you could try if you really needed it flat on top would be to use a tennon joint with the parent stock for the tennon being polished and just under the size of your pritchel hole. What are your specific planned uses? Mind if I steal your bolster plate idea sometime? Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 18, 2013 Share Posted May 18, 2013 I like the idea, I'm a big fan of multi taskers on my tool shelves. Spacing holes has a pretty straight forward rule of thumb regarding strength. Leave the radius of the hole between holes and it will NOT diminish the strength of the member. Now, this is a different kind of strength, it's frame member strength and why so many things have holes drilled in them for weight saving without loss of strength. Using it as a bolster will probably want a little more than the radius between holes and make it the radius of the larger hole. More spacing, don't use quite so straight forward gradation by size. It'll really help selecting the right size if you're moving fast but there is another way that'll let you put more holes in the plate. Put the small holes between the large holes and the really small ones can be offset in the hardy hole, they don't have to be in a smooth circle. For instance a 1/4" hole can be on the close (to the prichel hole) and a 3/8" can be on the far side. They won't interfere with each other and will be handy. Or, how about this. Instead of only bolster holes why not some rivet sets? You have ALL the rest of the plate right on the face, why not use it? An easy turning wrench is as simple as making an exaggerated bending wrench so the pins will line up on bolster holes across the center. You can leave it hanging from something handy and out of the way but it'll be right there when you need it. DARN! Gotta take a dog to class and I was really getting into this. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Black Frog Posted May 18, 2013 Author Share Posted May 18, 2013 Great ideas all around, thanks! This first stab at the design for my anvil, but wanted input here before starting- glad I did. Quote Link to comment Share on other sites More sharing options...
Black Frog Posted May 18, 2013 Author Share Posted May 18, 2013 Btw... no way is this my idea, I saw it at Brian's and knew immediately that it was nice idea. After using it in action, I knew I would be making one for myself. Brian's plate only had round holes, but the size of plate for my anvil would allow for a larger array of holes. So why not add the square holes too..... Quote Link to comment Share on other sites More sharing options...
Jim Coke Posted May 18, 2013 Share Posted May 18, 2013 Greetings again Frog, On the down side... Small hole bolsters have a tendency to get worn from misses .. If this happens you will limit the universal purpose.... You will be looking for another one.... I make smaller bolsters that if the wear its easier to replace just one ... Still a neet idea if your a good shot.... Great thinkin...... JIM I'll bet you made a set of my vice jaw spacers Quote Link to comment Share on other sites More sharing options...
windancer Posted May 18, 2013 Share Posted May 18, 2013 Yesteryear Forge is selling a bending jig- if you check that out you maay get some other ideas bouncing around with your bolster plate. Just my .02. Post it when you finish it :) Dave Quote Link to comment Share on other sites More sharing options...
VaughnT Posted May 18, 2013 Share Posted May 18, 2013 The Yesteryear bending jig is a very neat idea and has some features that you should incorporate into your design. For the square holes, I'd do them first. After they've been drifted to final shape, you can drill the other holes and not worry about them getting deformed. Do you do a lot of work on small stock? Is there really a need for a .125" hole? Love Frosty's idea of stacking the smaller holes together to conserve space. This would open up more area for a yesteryear-like bending jig...... Quote Link to comment Share on other sites More sharing options...
Burnttoast Posted December 29, 2015 Share Posted December 29, 2015 what type of steel is preferred for this project? Quote Link to comment Share on other sites More sharing options...
Everything Mac Posted December 29, 2015 Share Posted December 29, 2015 Hey Burnttoast - welcome to the forum. I just used mild steel for my one. Go ahead and edit your user profile to include your general location as you might find a few IFI folks near by. All the best Andy Quote Link to comment Share on other sites More sharing options...
Burnttoast Posted January 2, 2016 Share Posted January 2, 2016 ok....got it........im in the US, made one from a chunk of T1 Quote Link to comment Share on other sites More sharing options...
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