brian Posted January 20, 2008 Share Posted January 20, 2008 Another thought(lot of thunkin' going on here) I get my trusty gas axe and angle grinder and carefully cut a cam out of 3/4 inch or so plate.Cam to go from 0 to 2 inches in one revolution, approximately same amount of travel as a flypress. Attach cam to shaft made of torsion bar to give it a bit of flex and put a fly wheel on the end of shaft . Make a ram with a roller on top end so cam won't jam (hopefully) when I spin the fly wheel.Bore a hole in the other end to take tools. Mount it on a two pillar frame with a substantial plate under the ram Reckon if I adjust the ram so the flywheel gets some speed up before it hits the steel it should give the same force as a fly press. You think this might work or would it just destroy itself?:cool: Quote Link to comment Share on other sites More sharing options...
matt walker Posted January 20, 2008 Share Posted January 20, 2008 I think I like your thinking. How about a sketch? Matt Quote Link to comment Share on other sites More sharing options...
Dale Russell Posted January 20, 2008 Share Posted January 20, 2008 Brian , youse need ta build youseself 1 of these wish i could say it was mine ... Dale Russell Quote Link to comment Share on other sites More sharing options...
brian Posted January 20, 2008 Author Share Posted January 20, 2008 I'll see if I can get a sketch up Matt.Might take me a while to figure out how to upload it. Quote Link to comment Share on other sites More sharing options...
brian Posted January 20, 2008 Author Share Posted January 20, 2008 I think I like your thinking. How about a sketch? Matt Rough sketch Matt but I think you'll get the idea. Cam Press - Blacksmith Picture Gallery Quote Link to comment Share on other sites More sharing options...
skunkriv Posted January 20, 2008 Share Posted January 20, 2008 As drawn I think it will work...once. Assuming a heavy enough flywheel to get any work done I think the axle will bend. Could move the supports in near the cam though. Interesting. Quote Link to comment Share on other sites More sharing options...
brian Posted January 20, 2008 Author Share Posted January 20, 2008 As drawn I think it will work...once. Assuming a heavy enough flywheel to get any work done I think the axle will bend. Could move the supports in near the cam though. Interesting. Yeah,there's quite a few things to work out,move the supports closer,rig up a spring to keep the ram up. I think a truck axle would take the twisting but may have to be fairly massive to stop it bending on impact.May be a tractor axle? Think I'd use plain bearings rather than ball or roller ,shaft isn't going to move fast. Quote Link to comment Share on other sites More sharing options...
John B Posted January 20, 2008 Share Posted January 20, 2008 Would there be a problem with pulling on handle as it has to go nearly 1 full rotation and have to be fairly long for pressure required? Quote Link to comment Share on other sites More sharing options...
brian Posted January 20, 2008 Author Share Posted January 20, 2008 Point taken John, I have never used a fly press but I get the idea you don't use the full rotation ,just sort of bump it down. If I get a bit of free travel before contact and use a fairly heavy flywheel would it build up enough momentum to be useful? Also thought of putting two cams side by side,one from 0 to 2 inches and another from 2 to 4 inches the second cam running in a step in the ram so I get 4 inches of travel in two rotations. Quote Link to comment Share on other sites More sharing options...
matt walker Posted January 20, 2008 Share Posted January 20, 2008 Thanks for the sketch Brian. I like it. A lot of us could build that much better/easier than we could cut the fast 4 lead thread screw and nut. Matt Quote Link to comment Share on other sites More sharing options...
Ice Czar Posted January 20, 2008 Share Posted January 20, 2008 use a clutch build momentum then engage the flywheel ;) Quote Link to comment Share on other sites More sharing options...
habu68 Posted January 20, 2008 Share Posted January 20, 2008 Brian, What you have drawn is a punch press, they use a crank shaft to produce the same motion. I think the problem that you will have is the same one you have with a punch press when it does not completely punch the hole in the part on the first pass. The full force of the fly wheel goes to the frame. The inclined plane of the screw allows the force to bounce as the fly wheel bottoms out. You haven't lived until you are standing next to a half ton of tooling when it comes apart and falls on the floor. If the tool locks up without breaking the frame it will be a real job to reverse the cam on the piston. look at the spring system on the little giant power hammer the springs allow the crank to pass through the dead stop while storing the excess energy that would snap the frame. Idea, use a auto crankshaft, bearings and make rods to fit. Good thinking outside the box. Quote Link to comment Share on other sites More sharing options...
habu68 Posted January 20, 2008 Share Posted January 20, 2008 Here is a small punch press about 3 to 5 tons (estimated by me) note the size of the frame.http://www.naabmachinery.com/images/Diamond.jpg Quote Link to comment Share on other sites More sharing options...
stretch Posted January 20, 2008 Share Posted January 20, 2008 I have a 30 ton punch press that I tried to use the way you are trying to use it. It is very hard to get it unstuck when it doesn't go its full stroke. I did it for 2 days to finish a job then took the flywheel and all the other stuff and making it into a hydraulic press. It is very hard on the body unsticking a stuck punch press for 2 days. If you had a 100 ton and did 30 or 40 ton work with it, it might not stick, because it would be big enough to finish the stroke. If you tried the cam idea and made sure it didn't go over or close to going over dead center and bounced it back up it might work. Quote Link to comment Share on other sites More sharing options...
nonjic Posted January 20, 2008 Share Posted January 20, 2008 I do alot of work on 'eccentric shaft' forging presses, and in a nutshell its got absolutley no chance of making a useable open die (free forging) press. They are good for closed die work but the forces involved are massive. The medical bills youll cop from building a machine like youve sketched will make the $A 1000 ish for the flypress seem very reasonable indeed. really, dont even try it. (I do know what im on about, and can give numerous reasons why not to do this, but it would take about an hour, trust me on this one.) Quote Link to comment Share on other sites More sharing options...
Dale Russell Posted January 21, 2008 Share Posted January 21, 2008 Brian , this is what i ment ta put up Quote Link to comment Share on other sites More sharing options...
R Funk Posted January 22, 2008 Share Posted January 22, 2008 I feel that the cam operated "fly press" holds some merit on from the standpoint of ease of construction. However the problem I see is the lack of adjustability. If the thickness of the work changes or for example if the work needs to be drawn down from relatively thick to thin, on a traditional flypress, the "working zone" can be adjusted by giving the flywheel another 1/2 turn or for that matter another 2 turns to keep the tooling in the active and desired working zone. In the case of the cam operated press, something else must be adjusted to keep the working zone in the 2/3 to 7/8 range of cam travel. This would require an adjustment system, such as a threaded rod or turnbuckle in the force transmission system or blocks under the work, adjustment of the bed or the location of the camshaft. I have not yet been able envision an adjustment system that would be anywhere as simple as just giving the flywheel another turn or so. If alot of high volume production is desired, that does not require significant adjustments of the working zone, the cam flypress should be considered. I trust I have made myself clear without being too wordy. If I have not made myself clear, please respond and I will try to clarify. Quote Link to comment Share on other sites More sharing options...
brian Posted January 22, 2008 Author Share Posted January 22, 2008 In the case of the cam operated press, something else must be adjusted to keep the working zone in the 2/3 to 7/8 range of cam travel. This would require an adjustment system, such as a threaded rod or turnbuckle in the force transmission system or blocks under the work, adjustment of the bed or the location of the camshaft. I have not yet been able envision an adjustment system that would be anywhere as simple as just giving the flywheel another turn or so. I think a large threaded rod combined with spacers under the work. Want to use it mainly for repetitive work.I can use the power hammer for drawing out. Quote Link to comment Share on other sites More sharing options...
R Funk Posted January 23, 2008 Share Posted January 23, 2008 If you are going to use it for mainly for repetive work, this cam design could work. However think through the length of stroke issue. You might want to consider having several interchangable cams allowing you to select the stroke length versus tonnage. The longer the stroke the less tonnage available. One more comment is make certain that the press can not stuck on bottom dead center. Shape the cam so that it can not get stuck, that is keep the cam active with no dwell at the bottom center. This will allow the wheel to kick back at the end of stroke as a traditional fly press does. Getting a press stuck on bottom center can be very difficult to clear. It is not unsual for stamping presses to have electric heaters in the frame to heat the frame, increasing the lenght of the frame and releasing the tension and allowing the press to be unstuck without dissassembly of the press. Quote Link to comment Share on other sites More sharing options...
brian Posted January 23, 2008 Author Share Posted January 23, 2008 I do alot of work on 'eccentric shaft' forging presses, and in a nutshell its got absolutley no chance of making a useable open die (free forging) press. They are good for closed die work but the forces involved are massive. The medical bills youll cop from building a machine like youve sketched will make the $A 1000 ish for the flypress seem very reasonable indeed. really, dont even try it. (I do know what im on about, and can give numerous reasons why not to do this, but it would take about an hour, trust me on this one.) I will bow to your greater wisdom John, pity ,I thought I had something there but I think I'll try and find a proper press rather than risk the injury. Quote Link to comment Share on other sites More sharing options...
nonjic Posted January 23, 2008 Share Posted January 23, 2008 Brian, I wasnt trying to be a smart&rse, and with a lot of effort & engineering you could just about make a useable cam press that would be as good as a flypress for certain applications. The main areas of concern on cam, or eccentic presses are,.. The elastic circuit of the frame needs to be immensly strong, any weak welds and it will burst it. The ram needs to be immensly well guided, any offset load and it will ' kick' & jam unless its very well guided, or it will break the crank, or cam holding shaft. (or the weak bit whereever that is) You need a big end, and a pitman, and pitman end bearing to give true vertical motion of the ram (starts to get complicated to make) , otherwise the cam would 'wipe' or pull the hot metal (instead of just pushing it down, (desired)) You may need some kind of clutch mechanism to release the stored energy into the work, it only needs to malfunction once (double stroke, engage late etc) and it will bite you. if you go for a clutch you need a brake - these then need sequencing somehow Factor in some method of stroke adjustment, or raising the bottom tool (screw, or more commonly a 'die wedge' ) and your into making a pretty complicated machine. I figure this is why the design of the flypress has changed so little since the very clever victorians deigned the basic configuration - Its the same with Naysmith and the hammer! Any specific questions on the design your planning I will try and give you some help with though ! Quote Link to comment Share on other sites More sharing options...
nonjic Posted January 23, 2008 Share Posted January 23, 2008 this is what they occasionally go for in the uk ! fly press on eBay (end time 23-Jan-08 22:24:43 GMT) Quote Link to comment Share on other sites More sharing options...
NeatGuy Posted January 24, 2008 Share Posted January 24, 2008 What you are describing is a stationary mechanical nibbler like a Pulmax or Trumpf, etc. The mechanism in your diagram looks exactly like a large Savage nibbler that I have. Check out nibbling machine at the uspto. Some nibblers like the Pulmax use a fine thread screw in the lower tool holder to adjust the lower tool. Some like the Trumpf use a motor with a foot peddal to raise and lower the upper tool. No nibbler that I have used has a clutch as the machine runs constantly. On the Pulmax the upper tool is controlled by a linkage the controls the stroke length of the punch. I use these machines constantly for both hot and cold work. I can not speak enough to the versitility of these machines. IMHO they are also highly under utilized by the blacksmith community in general. That said nibblers or any machine constructed in a similar fashion are a different tool than a fly press athough both can be used for some similar applications. Here is a little extra info I have comipled on nibblers. Quote Link to comment Share on other sites More sharing options...
Jmercier Posted January 24, 2008 Share Posted January 24, 2008 Yeah, fly presses are ridiculously cheap in the UK >_< That same thing would have fetched around 500 bucks in the US. Manual fly presses were never that common over here. I got mine for 350 (including the very heavy original stand for it with mounting hardware and all) and got quite a good deal. Quote Link to comment Share on other sites More sharing options...
matt walker Posted January 25, 2008 Share Posted January 25, 2008 Let's kick this around. What about instead of 4 smaller threads, one big one. Imagine taking say a 2-1/4" shaft and wrapping two pieces of (guessing 1/4" X 1-1/4") steel around it using a rosebud. Experiment with paper to see what width gives you the advance to degree of turn ratio we want. Then take one of the pieces off the shaft. Drill through the remaining flat bar into the shaft, plug weld numerous close places and grind clean. Now we have a big fast screw. Next bore a block to the OD of shaft plus the flat bar. Insert the other bent flat bar we saved from wrapping the shaft, into the bored hole in the block and plug weld through holes drilled before insertion and clean up with a die grinder to make the nut. Matt Quote Link to comment Share on other sites More sharing options...
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