Tips for making simple steel rule dies

[leathersmith]

Hi. I have a leather goods shop and I'm interested in doing some simple steel rule dies in house. I've purchased some 2pt. steel rule from Helmhold and a small hand held router and a cutting bit. I'm wondering if anyone can direct me to a site or a book where I can read about the step by step process of cutting the dieboard and inserting the steel rule to complete the die.
Thanks in advance.

[One of Many]

I have purchased several Steel Rule dies over the last 20+ years. I have some material to make up an emergency die if such a case came along. So far it hasn't, but I don't think it would be to hard to cobble a usable die together with fair results on foams etc.

Most small shops tend to lay out the pattern on a chunk of marine grade 12ply. Then use a drill bit in strategic points along a run every 3-5" and at radius tangent points. The holes allow a blade to pass through to start cutting a slot with an over arm jig saw, leaving periodic tabs where the Steel rule material is notched out to jump over the tab. The tabs in the plywood keep the areas inboard and outboard of the rule sections in one piece. For better tolerance than eyeball cut slots in the ply, some shops will have the slots in the ply laser cut. I have been able to get accuracies of better than .010 with the laser cut ply compared to their standard .030 by hand.

The Steel Rule material is pre-bent to the shape of the slot cut in the ply with various die rule bending methods. Then pressed into the slot so it bottoms out at the back side of the ply. Hence the notches in the steel rule will be as deep as the ply. The rule height above the ply at least the thickness of the material being die cut. A backer of aluminum plate gives the Steel Rule some support during a cut. Some dense sponge foam can be placed inboard and outboard of the Steel Rule to act as a stripper of the material being cut.

I have never seen a detailed book showing the process, nor a web site that has much direction.

You could find a Die maker in your area and ask for a basic lesson for simple forms. Most of the dies I have needed were in the $30-$100 range. Not too bad and hardly worth my time to learn how as often as I really need one.

DC

[txcowdog]

You also need the machine to notch the back side of the rule to slip into the area that is not cut through where you drilled the holes to start your jigsaw. For $30-$45 I always buy the die. I've been in the leather business 30 years and it is not worth my time or investment in the tools for $30.

[leathersmith]

Thanks for the overview. Yes, I would certainly agree that it would be better to buy the die instead of trying to do it in house. I was just thinking that it might be useful to do some simple dies for prototype leather goods, so I can fine tune before I go into production.

That said, I suppose the real question is whether it is feasible to do such simple dies on a limited budget. More specifically:

1) Is it possible to bend rule by hand using, for example, wooden forms of some sort:

2) Is there a make-shift way to notch the rule without having to buy a professional notcher?

3) How is the rule bonded in the areas where the terminations meet (such as on a circle)?

I certainly believe that this type of work is best left to the pros, and if I could find a die shop willing to do work with a 2-3 day turnaround and at prices in the $30-$45 price range, I wouldn't even bother with this experiment (most of the estimates I've gotten have been much higher -- perhaps I've been talking to the wrong shops or my patterns are too complex).

[leathersmith]

By the way, any references on reliable die shops (ideally in Greater New York) would very much be welcome! I'd love to put aside this experiment in favor of working with a reliable die maker. Thanks.

[One of Many]

Originally Posted by leathersmith Thanks for the overview. Yes, I would certainly agree that it would be better to buy the die instead of trying to do it in house. I was just thinking that it might be useful to do some simple dies for prototype leather goods, so I can fine tune before I go into production. That said, I suppose the real question is whether it is feasible to do such simple dies on a limited budget. More specifically:

This is not a bad plan. It is just the overall investment to get started can get pretty high for less than 10 dies per year. This could turn into another nitch market service for your area though!

Originally Posted by leathersmith 1) Is it possible to bend rule by hand using, for example, wooden forms of some sort:

Mandrel bending on a diacro type of radius hand bender would be a ton more accurate with the rule spring back requiring some over bend. You could simulate this with dowel pins and various disks, but the idea is to get smooth radius's without kinks.

Originally Posted by leathersmith 2) Is there a make-shift way to notch the rule without having to buy a professional notcher?

Look into a uni-punch and possibly place that on an arbor press etc.

Originally Posted by leathersmith 3) How is the rule bonded in the areas where the terminations meet (such as on a circle)?

The ends are ground to a tight fit, butting up together when pressed into the saw cut slot. The saw cut curf needs to be slightly smaller than the rule stock thickness so it grips tight as a press fit into the ply.

Originally Posted by leathersmith I certainly believe that this type of work is best left to the pros, and if I could find a die shop willing to do work with a 2-3 day turnaround and at prices in the $30-$45 price range, I wouldn't even bother with this experiment (most of the estimates I've gotten have been much higher -- perhaps I've been talking to the wrong shops or my patterns are too complex).

The west coast seems to have several of these shops in each metro area. Competition helps keep the prices reasonable, but sometimes getting quotes from multiple shops will give you an idea who is willing to compete. I don't mind calling the high bidder back and let them know how far off they were if it goes beyond a 50% difference in price.

DC

[machinbird]

Originally Posted by leathersmith 1) Is it possible to bend rule by hand using, for example, wooden forms of some sort: 2) Is there a make-shift way to notch the rule without having to buy a professional notcher? 3) How is the rule bonded in the areas where the terminations meet (such as on a circle)?

(1) Yes you can bend the sharper bends in a vice, the gentler bends in your hands or an improvised 3 roll bender.
(2) Use a Dremel tool with an abrasive disk.
(3) Usually the rule is butted together. You can also braze it if you are quick and do not heat up the cutting edge too much.
Considering the poor results versus time expended, it is much better to purchase steel rule dies. Do it yourself work on steel rule dies is best left for repairs. If your die quotes are too high, perhaps you have too many punches in your dies. If so-perhaps you can be creative and do without.

[machinbird]

Originally Posted by leathersmith By the way, any references on reliable die shops (ideally in Greater New York) would very much be welcome! I'd love to put aside this experiment in favor of working with a reliable die maker. Thanks.

Try:
NATIONAL STEEL RULE DIE CO.
17 WEST 17TH ST
NY, NY 10011
TEL 212-243-2680/FAX 212-675-5120
I used them a few years ago and they were both good and fast.

[machinbird]

A last "By the way" and then I'll shut up. There is another way to make steel rule clicker dies. It involves an interior wood pattern cut in the desired shape and a rule that is attached by 10-24 screws with square nuts anchoring every 1 inch or so of the perimeter. This type of die is used for short run types of projects (~1 month of steady cutting). This method is slightly more expensive than the conventional steel rule die, but not too bad. It is much better suited to clicker type cutting in that you cannot pull the rule out of the form by getting it stuck. You do have to periodically check the screws around the perimeter for loosening and replace any broken/bent ones.

[leathersmith]

Thanks for the feedback so far.

I'm not exactly sure I understood the process of bolting rule to wood patterns in the previous post and how this would simplify making home made dies.

Here is my informal assessment of doing home made dies with limited equipment based on what I've read:

- cutting the die-board is fairly routine if you have a steady hand and a good jigsaw.

- cutting the rule is also be fairly easy if you have a sheet metal cutter.

- inserting the rule into the board is also not particularly difficult if you have a decent mallet

- bending the rule, on the other hand, is the really critical step which requires very expensive machinery. 2pt. rule is fairly rigid steel. It is one thing to bend a long piece, but an entirely different story if you have to manually bend precise arcs and curves on a complex pattern.

I'm wondering, therefore, if there is any reasonable way to successfully bend patterns in steel rule without spending thousands of dollars on Helmold benders. Should I perhaps limit my home made dies to simple squares and the like? Would I be able to figure out a way to bend rule with a home made jig or am I just wasting my time?

[leathersmith]

Another question...when purchasing a steel rule die from a die maker, what is the step that adds the most to the final cost, the cutting of the board or the bending of the rule? Would it be feasible, for example, to cut board myself and simply request that a die shop bend the more complex patterns for me? Just a thought.

[machinbird]

Originally Posted by leathersmith Thanks for the feedback so far. I'm not exactly sure I understood the process of bolting rule to wood patterns in the previous post and how this would simplify making home made dies. ........................................................... I'm wondering, therefore, if there is any reasonable way to successfully bend patterns in steel rule without spending thousands of dollars on Helmold benders. Should I perhaps limit my home made dies to simple squares and the like? Would I be able to figure out a way to bend rule with a home made jig or am I just wasting my time?

Leathersmith: Think about the process of die cutting leather. It is expensive stuff and it has flawed areas in it that you need to cut around. Most leather is cut with clicker dies. If you want to get maximum yield from a hide, you have to be able to see exactly how to place the die. If the rule is mounted in a large die board, that can be hard to do. By bolting the rule to the wood form, you get a die that is exactly the same size as the piece being cut.
As I mentioned earlier, most clickers dies cut on a hard plastic surface and the base itself is glued to a heavy wood die board or other wood base. By cutting on plastic, it isn't such a big deal if the press goes a little too deep. Do that on steel and your die is ruined. Also, if the die is pressed too far into the plastic and gets stuck, a few light hammer taps will free it. The wood base under the plastic is necessary because the cutting surface will eventually be filled with small cuts and this will cause the plastic cutting pad to bow away from the supporting surface if it is not firmly adhered to it.
The screw attached rule die was described so you could order the right type of die for practical cutting should you wish to go with the company I mentioned previously. You can also make this type die, but you would probably want to punch the holes in the rule rather than drill them. The screws are anchored by placing holes for the square nuts along the perimeter of the die, set back about 3/4 inch from the edge. Drill a clearance hole through the edge of the die board into the hole for the nut, put your screw through the rule into the clearance hole and drop the square nut into the anchor hole. Engage the nut with the screw, tighten, and go on to the next. Tedious but it can be done. The rule is normally brazed on this type of die instead of butted. The pros are set to do all this accurately and quickly. It isn't so much skill as having the right equipment.
As far as making your own dies. start simple and gain experience-best way to go. Let the pros do the hard stuff until you gain experience. Look at what the pros are doing and try to copy it. At least, that's my 2 cents.