Asciidv Posted December 21, 2020 Share Posted December 21, 2020 (edited) Andy, I was thinking on similar lines, but cutting the petal shape first and then forming the petals and cutting the outer square. The petal cutting die has to retract to permit the forming and like you I wondered about a heavy duty spring although in reality I think it will have to be a latch. Edited December 21, 2020 by Asciidv Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 It seems that the faceted punch works just fine, which simplifies things: 3 Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 21 hours ago, andypugh said: And would a hexagon work? Each facet of a hexagon would make 1/6 of a gill..... Quote Link to comment Share on other sites More sharing options...
Asciidv Posted December 21, 2020 Share Posted December 21, 2020 O.K. Andy, let us see you turn the tips over! Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 2 minutes ago, Asciidv said: O.K. Andy, let us see you turn the tips over! I have given that some thought, and I think it has to be a second-op, I can't see a way to get the tip-turned shape out of a die that can also make the petals. Quote Link to comment Share on other sites More sharing options...
David Herbert Posted December 21, 2020 Share Posted December 21, 2020 Is there any need to turn the tips over ? Possibly to allow the gills to sit closer to each other ? If a round hole were punched first, possibly in the same strike as the external shape, it would reduce the height of the petals and centre the pentagonal punch. David Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted December 21, 2020 Author Share Posted December 21, 2020 Thanks for everyone's effort on this. Here is a photo showing the recess on the profile from the underside on the "new gills" Here is the best image I have found of the gills used in 1908. I am only reproducing a very small amount of the photo as I am not certain of the copyright. I could easily convince myself that neither the circular (half toroid) feature or the turned over petals are present; I think both these features are to give consistent spacing (spacing looks fairly inconsistent in the photo). Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 5 minutes ago, BenHawkins said: Thanks for everyone's effort on this. Here is a photo showing the recess on the profile from the underside on the "new gills" What is the corner radius? (not that there necessarily is a corner radius on the original ones) The torus is easy, I think. Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 7 hours ago, Asciidv said: I wondered about a heavy duty spring although in reality I think it will have to be a latch. https://en.wikipedia.org/wiki/Types_of_press_tools says: In general, cutting force (CF) can be calculated using the formula: CF =L x S x ζmax The square has approx 90mm perimeter, is 0.25mm thick and the shear strength is about 275N/mm2: So to blank out the square needs about 6kN. Zoro list a 50mm dia die spring with a stiffness of 700N/mm so even that would be compressed by 8.5mm. Cutting force could probably be reduced by faceting the die, as is done with Q-max cutters. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted December 21, 2020 Author Share Posted December 21, 2020 52 minutes ago, andypugh said: What is the corner radius? (not that there necessarily is a corner radius on the original ones) The torus is easy, I think. 3/32 but as you spotted I think the original was less. Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 I have what I think might be a workable (and makeable) design. https://a360.co/3pagTbb Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 6 minutes ago, BenHawkins said: 3/32 but as you spotted I think the original was less. And bigger is easier, as I don't have a slotting head... Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 21, 2020 Share Posted December 21, 2020 14 minutes ago, andypugh said: And bigger is easier, as I don't have a slotting head... With the latest update, this is less of an issue as I abandoned the square follower design, so the square die recess is only 12mm rather than 30mm deep. This makes it rather easier to mill with a 4mm cutter. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted December 22, 2020 Author Share Posted December 22, 2020 Is bending the tips of the petals as simple as forming a flared hole before starting to cut? Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 22, 2020 Share Posted December 22, 2020 19 minutes ago, BenHawkins said: Is bending the tips of the petals as simple as forming a flared hole before starting to cut? Looks tricky to make, how about you try it 🙂 I have been slightly busy... Quote Link to comment Share on other sites More sharing options...
Asciidv Posted December 22, 2020 Share Posted December 22, 2020 (edited) Andy, Ben, if you want sharper corners I can wire EDM the bits. It might be an advantage to wire EDM everything from tool steel so that hardening is not necessary, Barry. ( Ben, does what you have drawn give a completely turned over tip to the petal or just a little flange at the end of the petal ? Edited December 22, 2020 by Asciidv Afterthought! Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 22, 2020 Share Posted December 22, 2020 2 minutes ago, Asciidv said: Andy, Ben, if you want sharper corners I can wire EDM the bits. It might be an advantage to wire EDM everything from tool steel so that hardening is not necessary It would also be an easy way to get back-relief, Though my current design has turned features on the punch and follower. (the earlier link should now show a rather re-worked design, using much smaller bits of tool steel. Quote Link to comment Share on other sites More sharing options...
MatchFuzee Posted December 22, 2020 Share Posted December 22, 2020 I assume that you are planning to cut and bend more than one at a time. Quote Link to comment Share on other sites More sharing options...
Citroman Posted December 22, 2020 Share Posted December 22, 2020 (edited) A friend in France did make a tool to make those radiator "plates". Here you can see the shape of the punch tool. Edited December 22, 2020 by Citroman 2 Quote Link to comment Share on other sites More sharing options...
Asciidv Posted December 22, 2020 Share Posted December 22, 2020 I like this punch. Simple to make and producing 40 in a single stamp. Although after they have been punched they need cutting out, a laser profiler would make short work of the task. Only 350 swings of the fly press against 14,000......I wonder which the glamorous assistant would choose? Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 22, 2020 Share Posted December 22, 2020 10 minutes ago, Asciidv said: I like this punch. Simple to make and producing 40 in a single stamp. Looking at the eccentric layout of the punches I think that these probably stayed in one piece (which would make for a stronger but impossible to repair radiator) Quote Link to comment Share on other sites More sharing options...
Citroman Posted December 23, 2020 Share Posted December 23, 2020 They were made to make an citroen V-shaped radiator, so he had to make a left and a right side. The pins can be screwed out and moved over to the other side, to make the other side. You could make one with a few pins in a row and punch strips of steel and than cut them up? Quote Link to comment Share on other sites More sharing options...
andypugh Posted December 24, 2020 Share Posted December 24, 2020 Would these do? 2 Quote Link to comment Share on other sites More sharing options...
David Herbert Posted December 24, 2020 Share Posted December 24, 2020 Please send all your empty coffee tins to Andy..... David Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted December 24, 2020 Share Posted December 24, 2020 Great stuff! Tony Quote Link to comment Share on other sites More sharing options...
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