Modifying shop press

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I need to modify my 12T shop press but I could use some guidance on the proper way to go about it.  The overall plan is to install a 1/2" plate (12"x12") on top and bottom for use as a clicker press.Ideally would like to completely remove the crossmember/rod that the jack sits on.  In it's place I'd like to put a new piece.  I'd like to keep the stock crossmember together so I can use the press for its intended use if need be later down the line.I sketched a rough idea but I don't have an engineer's mind.  I need the steel plate to stay flat so it presses my dies evenly.  I also need to attach the steel plate to the return springs without drilling through the plate so the press face stays clean and solid.  Ok, let me have it.    ThanksLast edited by Monica; 09-12-2010 at 11:15 AM.Lincoln AC225 and CartLincoln WeldPak HD and CartOne hand
Reply:What you have looks good.  May want to put some gussets on the 1/2" plate.
Reply:I use a similar arrangement to install captive nuts around an 9" radius. I use 1" plates and it takes about 5 tons. Many pressing later and everything is still flat. I didn't modify my press, so I'm pressing from the center of the 1" plate. Half inch may or may not be stiff enough depending on your tonnage. Try it. If it bends you can straighten it and then sandwich another piece to stiffen it.
Reply:1/2" plates might not be thick enough. It probably will not bend permanently under 12 tons, but it might deflect during use and cause an incomplete cut. I'd recommend 1" or more. Also using thicker stock will allow you to weld to the back side without any warping. This is probably overkill, but overkill is better than having to repair it later.Last edited by fortyonethirty; 08-25-2010 at 02:34 PM.Ian TannerKawasaki KX450 and many other fine tools
Reply:With the proposed design, press force will attempt to crush a hollow tubular shaped cross-member; making a very heavy tube necessary. Of course forces should be exerted on the tube's vertical walls, not the flat.Rather than rebuild the cross member from tube, I think it would be better to install a filler piece into the "C" of an original type channel cross-member, making the drop at least flush with the flange,  and then attach the desired push plate to the filler.Maybe the existing cross-member could be modified to work with both operations?Good LuckLast edited by denrep; 08-25-2010 at 03:30 PM.
Reply:My suggestion?Leave the original parts alone and ADD your desired flat plate to things.  Just rig up a collar/socket that attaches to the original 'post' on the press.Or just make your clicker die setup as a 'stand alone' item that just sits on top of the existing press table and is then squeezed down by the existing press 'post'.And when you say "need the steel plate to stay flat", well once you start putting a load/force on the plate then it -will- start to deflect/bend.  If the plate/die is beefy enough, then that deflection can be pretty darn small.  But it would still be there. (small could be down in the less than a thou deflection for beefy dies.)There is flat and then there is f-l-a-t.  Your call as to which.And the plate could deflect during use and then return to 'flat' once the force is released.  That is what you want.  Because if the pieces bend and stay bent, then the pieces have exceeded their yield point and they are no longer flat or whatever shape you wanted them to be in and stay in.Hmmm, 12 tons and 1/2 inch plate?  It probably won't fail totally (break apart) but it -could- bend a bit during use and -might- take a slight bend.  Depending on exactly where the forces are going through things.For a 12 x 12 x 1inch plate loaded with 12 tons (24,000 lbs) in the middle of the plate and "simply supported" (engineering term, pretty much means 'resting on the edges/end and not clamped or 'fixed' in place) on/near two edges, the plate will bend or deflect about 0.03 inches.  30 thousandths bending.  The plate will spring back to 'flat' once the force is released.For a 12 x 12 x 1/2 inch thick steel plate, same load of 12 tons, the plate would bend about 1/4 inch. A plate 1/2 inch thick is only 1/8 as 'strong' as a 1 inch thick plate (sectional properties and the h^3 factor here).Make it out of 1+ inch thick plate IMHO.  Especially if you want things to stay or be flat during use.Last edited by MoonRise; 08-25-2010 at 03:41 PM.  The best laid schemes ... Gang oft agley ...
Reply:I don't know if this changes any thing but more details here.  I'll be using this for clicker dies on 6-8oz veg tan leather.  The actual contact point footprint of die to leather is very small, and it is sharp at that.Wouldn't this just be a case of the weaker material gets crushed first, or cut, as this case may be with the leather?  I figure my leather will be cut long before metal parts give way, right?  I appreciate the thorough discussion on it.  My brain is probably not looking at the design structure as critically as other experienced eyes may be   On the other hand, I don't want to miss the forest for the trees.I'll be considering changing the plate thickness to 1".  The compromise with 1/2" is its a fair function for the cost on these homebuilt presses.  I'm still all ears.Below is one of my dies.Last edited by Monica; 09-12-2010 at 11:15 AM.Lincoln AC225 and CartLincoln WeldPak HD and CartOne hand
Reply:You could use a 1 ton press for what you are doing.  I have seen cliker press with 3" air cylenders and 12" square platens used in production.
Reply:Originally Posted by denrepWith the proposed design, press force will attempt to crush a hollow tubular shaped cross-member; making a very heavy tube necessary. Of course forces should be exerted on the tube's vertical walls, not the flat.Rather than rebuild the cross member from tube, I think it would be better to install a filler piece into the "C" of an original type channel cross-member, making the drop at least flush with the flange,  and then attach the desired push plate to the filler.Maybe the existing cross-member could be modified to work with both operations?Good Luck
Reply:Originally Posted by GabZipYou could use a 1 ton press for what you are doing.  I have seen cliker press with 3" air cylenders and 12" square platens used in production.
Reply:At my friends work they use a clicker press for die cutting rubber to specific sizes and shapes.  One thing I noted when I messed around on it there is that they use a high density foam under the rubber so that the die does not get bent from the large amount of pressure placed on it hitting something hard after the cutting is complete.  Once it slices through the rubber it hits the foam travels a bit farther and stops. The die also has the same foam inside of it so that once the cut is complete the die pops back out of the material and the piece it cut also pops free on its own. Maybe something to consider so you dont mess up your dies.  The rubber that they cut is quite tough so I would guess its pretty similar to leather in that way.  Just some food for thought.\looks something like this
Reply:Originally Posted by ggarnerAt my friends work they use a clicker press for die cutting rubber to specific sizes and shapes.  One thing I noted when I messed around on it there is that they use a high density foam under the rubber so that the die does not get bent from the large amount of pressure placed on it hitting something hard after the cutting is complete.  Once it slices through the rubber it hits the foam travels a bit farther and stops. The die also has the same foam inside of it so that once the cut is complete the die pops back out of the material and the piece it cut also pops free on its own. Maybe something to consider so you dont mess up your dies.  The rubber that they cut is quite tough so I would guess its pretty similar to leather in that way.  Just some food for thought.\looks something like this
Reply:Monica,Maybe think of setting up your die 'rig' like a 'real' tool die.In words,- make a bottom plate, that has some beefy pins/posts at the corners;- make a top plate that can ride up and down over those pins/posts;- your 'cookie cutter' die attaches to the top plate/platen;In use, the lower platen would have your backing board of HDPE/plastic put on top of it (if you rig it up to also be located by the corner posts/pins, it won't shift around), then the piece of leather is put on top of that.  The upper plate/platen can either be attached via collar/socket to the 'post' of the press or it could just be part of the die set.  If part of the die set, you would probably want to put some springs into the die set so that the upper plate/platen rises up from the springs when the press is not pressing down.  Use the press to push down on the die and cut/stamp your leather. Attached Images  The best laid schemes ... Gang oft agley ...
Reply:Something like this Moonrise??http://all-a-cart.comWelding Cart Kits and accessories
Reply:Originally Posted by Monicalol yeah, those are the expensive clickers I use HDPE under the leather.  Leather needs to have a solid form underneath or it doesn't get cut properly.  The 'cutting board is soft enough it doesn't kill the die quickly.  The other piece to that is having a quality die.
Reply:Very cool.  Now, let me introduce a hitch. - I have multiple dies.  And right now I'm not even close to having a die for every pattern I use.Lincoln AC225 and CartLincoln WeldPak HD and CartOne hand
Reply:Originally Posted by MonicaVery cool.  Now, let me introduce a hitch. - I have multiple dies.  And right now I'm not even close to having a die for every pattern I use.
Reply:Originally Posted by ZTFabDo you make the dies??I would try to incorporate a common mounting system into all of the dies. Something that is the same on each die that has a corresponding piece on the top die of the press to mount them to.
Reply:Originally Posted by MonicaNo, I do not make the dies.  I guess I'd need one heckuva on/off magnet eh?That die I posted builds the holster in this picture (the ranch brand is a customer's, not my own).
Reply:Thanks Lincoln AC225 and CartLincoln WeldPak HD and CartOne hand
Reply:Paul - ZTFab,I can't see your photobucket attachment.  Corp firewall won't let it through.Monica,Attaching a cutter to the die upper plate/platen could be as simple as just a few small screws through the 'cross brace' on the top of the cutter into the upper plate/platen.  If most of the cutters are of a similar overall size, then try to standardize the screw hole placement or put the mounting screw hole in a standardized grid pattern of some sort and maybe make up a drilling/spacing jig to make the process of making the holes all the same faster and repeatable.Sort of like this.  The red dots are where holes go through the cutter die 'straps' and have some small(er) screws attaching to the bottom of the upper plate/platen.  "Small' as in probably -not- a 3/4 bolt.    Maybe more like a 10-32 screw.  Something like a  button-head cap screw would help to minimize any possible 'marking' of the material being cut/stamped if it pushed all the way up to the top of the cutter.  As opposed to say a plain slotted screw head that maybe got buggered up and has a burr on it that then makes a mark onto your leather pieces. Attached Images  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by MoonRisePaul - ZTFab,I can't see your photobucket attachment.  Corp firewall won't let it through.
Reply:Paul,Yup, that image attachment shows up now.  Same thing I posted/described, except your pic shows it in 3-D.    And you put some nice rounds on the edges of all the plates too.  And a chamfer on the top of the pins.  And a nice helical spring as well.    Some of the diagonal lines are showing some aliasing though.    btw, what software did you use to whip up that concept in?  The best laid schemes ... Gang oft agley ...
Reply:That's SolidWorks 2010As far as the aliasing lines go...I can't do anything for crappy video cards!! It must be something with the image transfer. It looks that way to me too when saved as a jpeg.http://all-a-cart.comWelding Cart Kits and accessories
Reply:You are not dealing with uniform sheet metal blanks.  Leather has imperfections and is irregular in shape.  The method OP was using has been worked out over the last 2-3 hundred years. The guide posts would just get in the way.You guys should decide soon. I'm sitting out here having 1" plates cut as we speak  not bad prices I think. 88 for two 12x12x1".Lincoln AC225 and CartLincoln WeldPak HD and CartOne hand
Reply:For someone with one hand, the guide posts in the die assembly are pretty much needed so that some springs can be put in to raise the upper plate/platen as the hydraulic press is retracted.Even for someone with two hands, I would say to just make the die assembly nice and sturdy with the posts and the thick plates/platens and all.Besides, -I- wouldn't want to be lifting and removing that upper plate/platen all the time.  A steel plate 12 x 12 x 1 inch thick weighs 40.8 pounds.  Do it thick, do it sturdy, and it will last a long time with no worries.  The best laid schemes ... Gang oft agley ...
Reply:Ok I'm home.  Plates are heavy!  Now, so I understand, why would I do a die press type like illustrated instead of staying with my top plate-bottom plate mounted on the press itself?  What concerns does it address?  What I don't like about this design is that it'll limit the size of what I can put in the press.  Because the below quote is true.  The other makers I know, well respected makers in the industry, do as I originally planned.  I'm not reinventing the wheel.   You are not dealing with uniform sheet metal blanks. Leather has imperfections and is irregular in shape. The method OP was using has been worked out over the last 2-3 hundred years. The guide posts would just get in the way.
Reply:IMO, having a nice sturdy bottom plate/platen and a nice sturdy top plate/platen with the 'proper' guide posts/pins removes most if not all of the 'wiggle' from the press having any effect on the cutting/stamping.  The hydraulic press you have and posted the picture of has a relatively LOT of wiggle from the press lower cross-bar wiggling around the press uprights.  It's just the way that type of press is made.  It's a force type of machine, not an extremely precision type of machine.Yes, if you just put the 'cookie cutter' on top of the leather piece which is on top of a 'backer board' (a plastic cutting board in this case) and then had a top plate/platen attached to the ram assembly of the press itself you can certainly cut/stamp the work sheet (leather in this case).But you already indicated that you only have one hand (literally) to do all this work.  And that you were tired of and found it difficult to position and line up things and make the cuts/stamps and wanted the cutting dies to come down nice and straight in order to make better and nicer cuts/stamps and last longer.Dies work better and last longer when they are big and beefy.  Back on page 1 of this thread, I roughly calculated how much the plates could bend/deflect under load.  For the same load/force, the 1/2 inch thick plate would bend about 1/4 inch while the 1 inch thick plate would bend 30 thousandths of an inch.  Big difference to me.If a die assembly with 12 inch x 12 inch plates is not big enough for the work pieces you have, then make it the size you need.  No big mystery there.  If 12 inch wide pieces of leather are fine, then you just run longer lengths of them through the 'open' part of the die assembly.  Just like the H-frame press has side uprights, you just put longer pieces through the tool/machine through the 'open' fore-aft direction.Just like lots of other tools come in different sizes (keep your minds out of the gutters    ), you have to use the appropriate tool for the job.  You're not going to work on ship-yard size plate steel with a little Dremel grinder just like you wouldn't use a 9 inch grinder to work on a jewelry.  A 3 inch zip wheel has its uses, just like a 14 inch abrasive cut-off wheel has its uses too.   A 6 inch wide press  brake has its uses, just like a 10 ft wide sheetmetal/siding brake does.  Etc, etc.Just like you are using a cutting die instead of cutting the leather out with shears or a sharp knife, there is often more than one way to get something done.  Trade-offs of time versus money versus production rate versus precision versus ease-of-use versus etc, etc, etc.  The best laid schemes ... Gang oft agley ...
Reply:I've been using this press for a little while already (with the plates that came with the press) and it does what I need it to do.  At this point I need a bigger press surface to do bigger patterns.  The 12"x12" I determined to be adequate on my holster patterns and max size I'd ever build to. I ran through the measurement thing when I was first ordering shipping boxes.  I had no clue as to what size my stuff was so I had the learn I don't think I need to change what I'm doing, I just need to make a new crossmember to attach to my plate instead of cutting off the rod (so I can use as intended).  Also I do not like the thought of pressing the center of a sq ft plate with just a 1" circle like I did on the 6" piece. It just didn't seem right; something to the effect of applying even pressure.As for cutting leather, I still do the majority of the work with an exacto.  And that's costing me 15-20min per order (and some arthritis & carpal tunnel to boot).  Transitioning all my pattern cutting to the clicker dies & press will allow me to be a bit more efficient and in turn more productive.  Until I get the press modified I'm not ordering any new clicker dies.Lincoln AC225 and CartLincoln WeldPak HD and CartOne hand
Reply:That seems like the thing to do>
Reply:Monica,Don't worry about the 1 inch diameter 'post' of the press 'hurting' that 1 inch thick steel plate.  The plate will be fine.  (even if you put the max 12 tons of force from the press onto the 1 inch diameter post, the 1 inch thick plate/platen of your die assembly would only see approximately 8 ksi of stress.  For steel, 8 ksi is nothing at all.  You could put an 8 ksi load onto some steel in almost any imaginable way literally forever and it will not 'hurt' the steel.  At all.  That is part of why I originally recommended making the die plates/platens out of 1 inch thick steel, so that there would be no worries or concerns about the plates/platens bending or breaking.)And that's another reason for the nice sturdy dowel pins for the top plate/platen to ride up and down on.  The pins make a nice place to put the springs that push the top plate/platen up when the press force is released and they also help guide the top plate/platen nice and straight up and down.  Don't worry.I'd say for a nice thick 1 inch plate to use some 1 inch dowel pins.  Real machinist tool/die maker dowel pins, not just some mild steel rod laying around.  The real dowel pins are h-a-r-d and straight and smoooooooth.Want to get 'fancy' with your die?  Have the machine shop "match machine" the two 1 inch thick 12x12 plates for the dowel pins.  Have them ream the bottom plate for a press fit of the dowel pins and then have the top plate reamed for either a slip-fit or for even 'better' sliding have some oil-impregnated bronze bushings put into the top plate/platen for the dowel pins to ride/slide in.As long as you are anywhere near the center of the top plate/platen (just by eyeball, no need to measure with a micrometer or such   )  and in between the two pins/posts, the top plate/platen will slide up and down and there will be no worries.  The press is pushing a little off center on the top plate/platen?  No worry, the nice thick top plate and the nice sturdy dowel pins help spread the forces so that the die top plate/platen just glides up and down and the cutting die cuts through the leather nicely.About the only thing to watch out for is that you don't keep cranking on the hydraulic press and flatten or deform your clicker die cutter.  Because 12 tons could do that to some thin (what is it, about 1/8 inch thick or so?) steel edging.  The 1 inch thick plates/platens won't care, but the clicker die cutter could get crushed.And I thought the center post of the HarborFreight (and most other) hydraulic presses of that approximate size (the 12 ton and the 20 ton) was more like 1.5 inches in diameter?  That would reduce the stress of the post pushing on the top plate/platen down to only about 5 ksi at 12 tons of force.  Which is even more of a DontWorry.Don't make a new crossmember for the press.  It is not needed at all.Really feel the need to weld -something- for the press just to make yourself feel better?  Make a collar that just slips over the end of the press's 'post' and weld that collar to a piece of, oh, maybe 1/2 inch thick plate a little bigger in dimensions than the post.  Drill and tap the collar radially for some bolts/screws (think big set screws) and put your new 'foot' onto the post.  It won't really change anything on the press or the die top plate/platen, but if it makes you feel better then go right ahead.    The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by MoonRiseReally feel the need to weld -something- for the press just to make yourself feel better?
Reply:Keep it simple: Place a 1" plate on the press bed. Place the "cushion" on the lower plate and locate the leather on the cushion.Set the die.Set the top plate.Press.This will get production going. Refinements can be added later.The single point push will be fine for the loads involved here.The down side is that the 40# finger and toe pinching top plate must be handled for each cut. Maybe a lighter upper plate could be built; possibly aluminum? The upper press plate could be tied to the press cross-member, but if the plate is 1"steel, then the retract springs won't be strong enough to handle the added weight. Of course any sort of fixed upper plate would hinder access during setup. Also, hands and fingers would be more at risk working blind between plates during setup. Again, keeping it simple, I believe I would build a ramped  "tray" of some sort, behind the upper plate. During setup, the upper plate could be pushed back into the tray.  The tray could be as simple as a solid shelf.Good LuckLast edited by denrep; 08-27-2010 at 12:54 PM.
Reply:Originally Posted by denrepKeep it simple: Place a 1" plate on the press bed. Place the "cushion" on the lower plate and locate the leather on the cushion.Set the die.Set the top plate.Press.This will get production going. Refinements can be added later.
Reply:Originally Posted by MonicaDang Moon, I thought this was a welding forum.   Of course it'll make me feel better doing the work myself.  Isn't that what all you folks do here?  Pay more for materials and time instead of buying a cheap overpriced thing because you have the satisfaction and pride of doing it yourself?  Many are employed doing the very stuff that makes them feel better.How is loading the heavy plates back up into my truck, finding a machinist, paying him for the work going to give me any satisfaction?  I make stuff.  And if I thought I couldn't do holsters nicer and better I'd be buying cheap production junk off sporting good shelves    So yes!  Also if the project suits my needs, doesn't maim or kill me, then why in the world should it bother you so much?  If you don't like it, fine, don't like it.  But don't start sniping at me in order to make me feel bad.  You're in the wrong buddy.  Go push someone else around.