Jump to content
I Forge Iron

Making A Metal Cutting Die


Recommended Posts

I have to cut 3" dia. and 4" dia round blanks out of 22 Ga. steel sheet, I'm using them for a product we make, so this will be an on-going thing for many years (hopefully). I've been drawing out the pattern with a template and then cutting them out with tin snips, but I would like to find something a little easier on my wrists.

The other night I noticed that I have a piece of 0.120" wall DOM (C1020) tube in my scrap pile that has the correct O.D. and was wondering if it would be realistic to file/grind the inner edge of the lip until I had a relatively sharp edge and then heat treat the cutting end of the tube. I was thinking that I could lay the sheet steel in my 20-ton hydraulic press and stamp the circle blanks out since the sheet metal is relatively thin?

If it wouldn't really hold up to the abuse, I may be better off having a machinist make me a set of cutting dies.

Thanks

Link to post
Share on other sites

In our town there is a waterjet that requires $225 per hour to hire. Seems to be just pricey enough to keep the street-walkers from getting little jobs priced. If a person had a whole bunch the price could go down per piece as the waterjet is very quick on thin stuff like that.



Carry on

Link to post
Share on other sites

You might get a few discs out of such a system but for ongoing production such as you intend you'll need a cutting die set with a mated bolster and a good alignment frame. You could make one but a pro will make it better and save you lots of time. You might find one stocked somewhere but not easily. Essentially you need a heavy block of tool steel with the hole size drilled and honed through it and a slot in one side to allow you to insert your 22 Ga. steel. Then a cylinder die of hardened tool steel is punched through the hole popping out your disc. This takes some power and is usually done on a hydraulic press setup Though there are other ways. For non-ferrous you could use a plate die but they won't cut steel for long.

Link to post
Share on other sites

On 22ga material a WJ can cut a 3-4'' circle in seconds. A 4'x8' sheet would be transformed into those little circles in less than 15 min......Setup would be a factor on the first go around, after that, not so much. BTW, waterjet outfits are just as hungry as everybody else....It pays to shop around.

Link to post
Share on other sites

Yeah, I've considered the water jet option as well. Was hoping to come up with something I could do in my own shop, but I may end up just cutting them with tin snips if I can't find a reasonable rate with a water jet. I do know a few people who have water jet and plasma tables, so I'll look into those options.

One of our clients is a local metal fineblanking company that does this type of stuff, but as mentioned, they do huge projects for the automotive industry and unfortunately my friend that managed the plant got transferred back to another plant.......would have been great to sneak in there one night and knock out about 500 of them in a matter of minutes with one of their blanking presses :D !

I do have a plasma cutter and have been toying with the idea of making an adjustable, magnetic-based circle cutting roller guide similar to the one that Hypertherm and others sell, but getting down around 3" dia gets a little tight. If I can work it out, I figured I could clamp several layers together and knock out several per cut. My other thought is to just use a circle template as a guide and free hand cut them like I do on thicker metal, may have to drill a small starter hole to keep them relatively clean. If the edges are a little off I can straighten them up on the vertical belt sander afterwards.

I really appreciate the input, saved me a bunch of wasted time & energy messing with trying to make a tool that wouldn't work well.

Link to post
Share on other sites

My friend Kevin at Potter USA makes dies he calls pancake dies. They are laser cut out of 10 GA A36 male and female which have a small tab on one end to hinge the die. They are used in his hand operated presses to stamp out parts for jewelry. I think your material is thin enough that this will work. Depending on how many you plan on doing. If it is alot I would make the dies cut out of a pre-air harden tool steel for longer life.

Link to post
Share on other sites

Seems to me that you might be able to find dies already made for this sort of thing.

Best would be to find someone to whom the punchouts were waste material and buy them at scraprate.

I had a friend making cowboy hats that had a bunch of circles cut from sheet metal at a price until he found the local Pipe & Iron supply store was selling them for a lot less as ends for welding on pipe. He said they were slightly domed but one whack on the anvil and they were flat.

Link to post
Share on other sites

Yeah I've been working multiple angles on this. Haven't thought about test caps for pipe......kind of sad to admit, considering I design process piping systems for a living :D! And pre-domed shape would be a bonus for what I'm doing with them.

I'm still searching around, there's a local scrap yard that handles a lot of industrial scrap metal from stamping and milling processes.

I've got a pretty good local source on new metal as well, I can pick up new 4'x10' sheets of 22 ga for $74 plus tax. According to the cad drawing I just did, I should be able to get (490) 3-1/8" or (297) 4-1/8" diameter circles out of one sheet, that would put the material cost at $0.17 or $0.27 each, respectively. I haven't been able to find anything else around that cheap. The local scrap yard sells at $0.25/lb flat rate, so I'll have to do the math to see if that would be a cheaper route, provided they have something that will work for me.

I'm going to head out to the shop now and see what I can do free hand with the plasma cutter and a pattern guide.

Thanks.

Link to post
Share on other sites

Do you remember the circle cutting fixtures for old O-A set ups? Basically a lot like a set of trammel points but the cutting torch fit on one of them. Instead of using a centerpunch to make an indent for the other point we used a speaker magnet that had a core with a central screwhole thus not putting a dent in our material.

Sounds like you could do the same for the plasma cutter

Link to post
Share on other sites

Look into laser cutting as well.

I used to make dies sets when I had my shop, and a good set will run a few grand, but will last a long time with proper care. It will depend on if have the equipment, and you want to do these in house, or farm them out. There are online services that can shop your item to shps that do this type of work.

It gets down to quantity,and time frames.

Link to post
Share on other sites

If you're doing production just buy a circle shear! Good grief you do NOT need anything fancy, I couldn't count how many blanks I cut on one in Dad's shop. With the hit manufacturing in this country is taking you should be able to find one used for reasonable. You'll need sheets square sheared first but most suppliers will do it for reasonable. Of course if you're shopping a square shear should be cheaper used than a circle shear.

Harold the cutting dies you're talking about are commonly known as "blanking dies" but that's around the jewelry and small scale crowd.

Frosty The Lucky.

Link to post
Share on other sites

I have had a certain amount of luck with using hole saws without the center bit.. think drill press and vice here... to create disks for various needs... Milwaulkee has carbide hole saws and it sound like you have enough equipment to make that work.

I would think either a drillpress or a magnetic portable drill would get this done.

I am planning on filing this one away, just in case I need to do this again..

Cliff

Link to post
Share on other sites

Magnetic drill presses are pretty cool. On #22 steel I think that a mag press would not work too well due to the thinness of the material, however I have also used a hole saw without a center bit in a drill press before. If you clamp down a plug, er hole, on top of the material as a drill guide you can likely get pretty good to excellent results, maybe even drilling a short stack at once.

Phil

Link to post
Share on other sites

Magnetic drill presses are pretty cool. On #22 steel I think that a mag press would not work too well due to the thinness of the material, however I have also used a hole saw without a center bit in a drill press before. If you clamp down a plug, er hole, on top of the material as a drill guide you can likely get pretty good to excellent results, maybe even drilling a short stack at once.

Phil


I actually chucked a hole saw bit in my drill press last night with the center bit removed, was going to try clamping the metal sheet down to a wood platform I'm building that will clamp into the drill press vice.

So you're recommending that I use the hole saw to drill a hole through something like 3/4" particle board and then clamp that on top of the metal to act as a guide to help prevent the hole saw from trying to walk on me, correct?
Link to post
Share on other sites

I actually chucked a hole saw bit in my drill press last night with the center bit removed, was going to try clamping the metal sheet down to a wood platform I'm building that will clamp into the drill press vice.

So you're recommending that I use the hole saw to drill a hole through something like 3/4" particle board and then clamp that on top of the metal to act as a guide to help prevent the hole saw from trying to walk on me, correct?


Yes.
Hardwood or plywood might be better and last longer than particle board, but particle board should be fine for a test run, might not last as long.
Phil
Link to post
Share on other sites

If you are looking for quite a few of these i think you will be amazed at how cheap you can get them cut out either by laser, waterjet or cnc plasma. This thin a material could be cut really quickly, possibly stacked so you could cut multiple pieces at once. I believe Randy who posts here and maybe some others have cnc plasma cutters and could give you a price. Waterjet will give you the best finish followed by laser and then plasma.

Link to post
Share on other sites

when I make candle wax dishs -- I use a HF air nibbler put in a vice - built a air valve foot switch - made a aluim pattern of size I wanted to need up with = that means pattern is small than size you get - shear stock into sqs - use vice grip welders clamp to hold & nibble away - clean up edges on belt sander

other way is find or make a pipe that has right ID when you use youre plasma cutter & cut them out

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...