Which steel bends easily?
 

I know we have a few machinists/metal fabricators here, so I'm hoping that someone will have some good advice on this: I'm working on a project where I need to bend short pieces of 3mm steel rod to a 3mm inner radius. I have been using drill rod so far, but it is a bit too hard and "springy" to get a nice 90 degree bend with a defined radius. Is there any other material than drill rod that would work better? The problem is that it needs to have a smooth finish (not necessarily ground though), and of course, it also need to be metric or a close equivalent.

Can we have more info? There are hundreds if not thousands.. how durable does it need to be? Will other metals be touching it (corrosion factor)? Does it need to be conductive? What is the normal temperature will it be exposed to? How are you bending it (pliers, pipe tools, sheet metal benders...?)

This is a lanyard loop for a pistol, it's a rectangular shape made out of 3mm rod and with 3mm radii. The strength is not critical, but it needs to bend easily and cleanly, and it needs a fairly nice surface so it can be blued without excessive prep. The tolerances are not extremely critical, maybe within 5/1000 or so.

I'm using a die do form it cold, and I can't really heat it. I have already tried to anneal the drill rod, it did make some difference but not much. I think something like 1018 cold finish round would work, but I can't find it in metric dimensions.

I have a piece or two...
 

Drill rod is too hard...I have some 10 series 3MM rod, it will work great for your lanyard loop... send me your address, (send to: gctomeks@msn.com ) and I'll send you a small length.. all I have left is some short pieces .1177" to .1180" dia. ... Some is cold rolled, some is drawn wire, so it, the wire, will have a slight surface hardening, not an issue for your radius... it's as close as your ever going to get! Believe me, I've chased this dog to death!...;)...best to you, til...lat'r...GT ...;)

gads.. has a be blue-able? I know a lot about metals but no clue about blueing.. I was originally thinking brass or a bronze but they won't finish.. seriously try the hanger but do a test blue first.. might come out a completely different value then the rest of the project. Find a gun that has a similar lanyard and look on numrich (gunpartscorp.com). Sorry I couldn't help more.. fof once I thought I could answer something on here! lol

it's a rectangular shape...

You might have a great deal of trouble with squared corners whatever you are using. They are quite difficult to square up..they tend to round over instead.

What kind of lanyard loop is this?

that's different...
 

Good catch Jerry! ....;)... I'd cut and sand it out of a piece of cold rolled 1008 to 1018 flat stock... only have to control one edge.... ;)....best to all, til...lat'r...GT

Yep, the rod tends to bend in the wrong places. This is for the P.38 (the loop has the same basic shape as paper staple), and I'm having a hard time getting the straight sections straight. I have made a pretty tight and sturdy die, where the head has a cap that I can tighten down to hold the rod. This die is then pressed into a tight fixture, which folds the legs of the loop. I don't have any pictures, but if you imagine the die and the rod as a "T" shape that is pressed into a square hole, you'll get the idea.

I have made the tool to pretty tight tolerances, but it's still difficult to get the shape right due to the small size. There's simply not enough rod for the die to hold on to when I bend it, and work hardening probably adds to the problem as well. I suspect that the original loops were formed hot, but I can't really do that as it would also weaken the die.

The only solution I can see is to find a softer rod that bends easily and cleanly, and doesn't spring back as much as the drill rod does. The ends need to be turned down before I bend it so the material needs to be fairly machinable, but the strength shouldn't be a problem at all.

You have mail.

The drill rod is hard alright, hard, springy and everything else that makes it difficult to bend. :banghead:

The cut length is about 1 1/4" so I don't need much, if I get enough for 2-3 attempts I'll be more than happy. This might save a lot of research so your help is greatly appreciated!

A lanyard loop for a P-38...Have you asked on any of the P-38 forums if anyone has one they would part with??? You would be surprised at what members of these specialized niche forums (like ours) have squirreled away... ;)

It's not for myself, I'm actually doing it on request from a P.38 forum member. It seems like there's many pistols with missing loops, and not enough loops available.

I'm actually on the lookout for a Mauser C96 with an OEM lanyard ring to measure...Neither of mine has one, and I don't know the diameter or wire gauge...And, like you say, most seem to be missing the original loops and keyrings have been substituted (now or in the past)... :(

I'm having trouble understanding why annealed drill rod, or whatever alloy, is still too stiff to form. When annealing steel, the longer it takes to cool down from cherry red to working temp., the closer it will be to dead soft. Try sticking the hot piece into a metal container of hot ashes, and allow the whole deal to cool overnight. This will act as insulation and buffer to ensure that the cooling will take as long as possible.
Also, have you considered doing the bending hot? It would be a lot easier, and if you're heating the piece to anneal, anyway, why not bend 'er when she's most plastic?

As far as the material's bending where you don't want it bent...
The points of contact opposite the internal apex of the right angle, on the outside edge of the piece, must be pretty close to the point of contact for the inside mandrel/pin, and it would help prevent the formation of a "dent" by each of these contacts if they were smooth-could even be flat. If you simply set up a square, inside corner and pushed/tapped the correct point along the length of rod straight into it with the tip of a screwdriver (Dress/grind the tip to remove the sq. corners, to the internal radius you desire.), that should do it for sure, if you're doing it hot. If cold, there will be "springback", so you'll need to make the corner more acute than dead square--this determined by how much the material of choice springs back after bending forces are removed, thus a little experimentation is necessary to determine the degree of acuteness necessary in order for the formed piece to be square after you let off bending and it springs back.

I hope this is clear. Sometimes difficult to put everyday activities and procedures into words! ...Try writing a set of instructions for tying a shoelace into a bow knot!

If I were doing this I might attempt it this way..Fashion a bar of steel with sharp edges and wrap your wire around it under as much tension as you can manage.. hammering the wire at the flats and corners with a lead or plastic mallet. Then cut your staple out with a rotary tool like a Dremel. Might take some adjustment on the size of the steel bar to get the size accurate enough but once it's perfected it would make a lot of staples quickly.

If I remember correctly..many times these types of wire bends are cut at the undersides of the corner bends. Removing some small amount of steel there allows for a clean bend.

When you get a staple you like it is very simple to fire blue it. Lay it on a fire brick and scan a plumbers torch over it..slowly feathering around it untill it magically turns to a straw color..take your torch away at this point as it will continue to heat and likely turn a beautiful fire blue. If you want a dark blue to black keep your torch on untill you see the fire blue..take it off and it will be done. Do NOT quench it in anything. Let it cool and oil it.

I have even fire blued relatively large parts like buttplates..

I think I follow what you say, and I think that the bending tool adresses the issues except for the "overbending" to allow for some springback. That part is not much of an issue though, it springs back less than 1/2 mm total (i.e. center to center) so it's easy to get the legs aligned by simply squeezing them slightly in the vise.

The section connecting the legs is the hardest part, it should be straight but ends up slightly bent. The tool has a screwed on cap that clamps it down in a 3mm groove (kind of the same way handle bars are attached on bicycles), and I have also inserted hardened dowels for the wire to bend over. In theory, the connecting section shouldn't bend, but it still does. It could be that the force required to bend the rod is enough for the cap screws to stretch a bit. This is one of the reasons why I don't want to heat it, there wasn't room so the screws are pretty small, and if I heat the tool they might just snap. This is a typical case where pictures will tell you more than a thousand words, so I'll se if I can snap a few so you can see what the tool looks like.

The "screwdriver method" works well (I use it every now and then), but there needs to be a neat, 3mm radius so I would have to come up with a rounded tool for it. Hitting the right spot with a screwdriver is fairly easy, but I'm afraid that it would be challenging to get it to bend exactly where it needs to bend if you use a rounded tool. I might try that if my contraption doesn't work.

As far as annealing the wire, I have heated it and stuck it in sand. I might try and heat the sand and see if it works better. However, it would be great if I can find a material that works without any prep, so we'll see what GT comes up with.

This project would be much less difficult if I could bend it first and then cut the legs to the correct length. The reason why I can't do that is that the ends need to be turned down to 2.5mm, which forms a shoulder that acts as a stop when you tap it into the frame. This means that I have to cut the rod to the exact length, turn both ends and center it carefully in the tool in order for the legs to come out the same length.

I have Walther's original drawing for this part and the cut length is 3mm longer than what I have found necessary, so it's quite possible that the factory had a way of trimming and forming the ends after the rod was bent.

If this small step on the ends of each leg is not extremely critical you might play with a Dremel sanding drum. I have found you can sand round rod like you need with the Dremel..clamp vice grips as a stop and let the drum naturally rotate around the wire tip from centrifical force and with a little practice I bet you could get a good enough trim. Dremel makes a very fine sanding drum that wouldn't take off too much per rotation. Worth a try..of course I am Bubba personified..I use a one half inch hand drill for a lathe.

You might want to try welding rods

I have actually done something very similar in the past, but with a file. I taped the loop where the step needed to be, and clamped it in the vise with the legs sticking up and flush with the tape. Then I used a "safe side" file to file down the ends, using the vise jaws as a guide. I found that filing them to a square first was the best way to stay on center, and once I had them squared to the correct dimension I rounded them off. It was actually a surprisingly quick and accurate method. I was planning to use Loctite, but I tapped it in for a dry fit and it stuck so well that I left it like that. Anyway, it seems like I'm going to make quite a few of these loops, so hand filing is not really an option.

And there's nothing wrong with using a power drill for a lathe, it's the quickest and easiest way to shave stubborn pins a tad and it's also the perfect way to reshape buggered screw heads. The easier, the better. ;)

I have already looked for welding rod, but haven't found any in metric dimensions yet. I might talk to my buddies in Sweden and see if they can find some for me. I have used it for other projects in the past and it's pretty nice to work with, the only problem is that some types contains too much nickel to blue well.

Ok, this should hopefully make the process more obvious…

Here’s the tool, a contraption of milled steel, drill rod and screws:
http://i47.tinypic.com/ffafm8.jpg

…and here’s the blank, with the ends turned down:
http://i50.tinypic.com/2wmkton.jpg

The head has a cap that you attach with two screws, this is what’s holding the blank and supposedly keeps it straight between the two 90 degree bends. You can see that the tool is pretty small, so I had to use 4-40 screws. I have also inserted pieces of hardened drill rod to make the tool last longer:
http://i50.tinypic.com/4jkzrs.jpg

The bearing surfaces inside the tool are filed down to a roundover, this makes the tool a bit smoother to work and prevents gouges on the outside of the loop:
http://i45.tinypic.com/1id63s.jpg

I insert the blank in the tool and tighten the screws…
http://i45.tinypic.com/5klkd5.jpg

…and it’s ready to press:
http://i48.tinypic.com/29lh3c2.jpg

The head comes out the other side:
http://i49.tinypic.com/35816ci.jpg
http://i48.tinypic.com/2yukpky.jpg

The cap comes off, and the loop is done:
http://i46.tinypic.com/33djqrq.jpg

…and here’s a few prototypes:
http://i46.tinypic.com/5ba70o.jpg

What grade drill rod? There are several typical harnesses. Have you tried finding a softer one? The proto types look great and the die should work really well. What part isn't right? Or is it just the hardness in general making it a pain?

It's O1 oil hardening rod, the only one I could find in 3mm. Finding metric stuff is not easy, I could go to the closest equivalent but I want to keep it as accurate as I possibly can.

To the casual observer these loops are ready to go, but if you look closer you'll see that the top part is not 100% straight and I'm thinking that a softer wire will take care of this. It's a very minute thing and most people wouldn't even see it, but I'm kind of anal so I want to do what I can to correct it. Also, I'm trying to learn the ins and outs of the noble art of wire bending, and I'm hoping that some research will help me in future projects. Really, many of my project stems from sheer curiosity, I just love to tinker and figure out how to do things like this.

Speaking of wire.. electrical wire is available in a lot of different materials.. the closest gauge would be 9, which would be slightly larger, 8 gauge would be slightly smaller.. typically copper, aluminium, silver, and gold, but you cal also find steel usually from salvage companys.. not sure how they blue up though.

Olle:
That's quite an ingenious bending jig that you have built--very impressive. My thought on why the back of the loop is rounded, although barely noticeable, is that the very small rod clamping screws might be stretching during the bending process, allowing the clamp cap to raise up, allowing the rounding effect. There has to be some tremendous forces exerted on those screws as the rod resists the sharp bending.

Of course, the entire jig system would have to be larger to allow for larger and/or more screws. This is just one more nuts observation.

By the way, I've done a lot of drill rod bending, but I am using W1 rod. It's my understanding that it comes annealed--at least it machines well.

Olle:
A few more random thoughts (a mental dump)--how about a tiny steel shim in the center of the rod, in the clamping cap. This would allow the corners of the bend to rise up a bit, which might offset the rounding effect by providing some rebound capability. Relieving the groove ends in the clalmping cap (high spot in the middle) would probably serve the same purpose, but would permanently change the cap. FWIW.

flat......is flat..
 

Hi Neil, I thought the same,..it is a nice fixture, but bigger would be better...Actually the loops are nicely done, too nice! The Germans stamped them out hard and cold, and if you look close, they show it!
The reason the loop bottom isn't flat is that instead of being secured in the clamp, the grooved ram should push directly on the staple ...and then, it needs a final block, with a 1.5MM rad. groove to press against at the bottom of the jig at the very last .... won't get flat until this happens?? The clamp is neat, but overkill... when the ram picks up the stock and starts to bend, any lateral movement should be over... If it does move, just make a final adjusting saddle fixture to finish, using the same ram... ... might be a two step operation!!!:eek:.... I call this type of discovery tool making, "Taking off on the short runway!" as your initial design seems logical but has built in problems that take much more work to cure.. but you have to give it a try, and of course, you go out thru the end markers.. but your 100% better equipped when you get on the long runway, should you be lucky enough to survive the attempt!...;)....It is a nice fixture, and you should be proud of the effort and result...you're close! Keep trying!...Best to all, til....lat'r....GT.....;)

+ 1 :thumbup:

Are you greasing it up real good before pressing??? I have to admit that it seems like what you have made would be quite adequate for a P-38 lanyard ring...maybe a bit of tweaking after the loop comes out of the press, but your prototypes look pretty good to me... ;)

Nicely done! Congratulations.

by the way......
 

you can also make the loops, just are you are now doing...then make a small base plate with two holes for the ends to set into, and using the same ram, press it flat from the outside of the loop...either way, inside or outside, you'll have to upset some metal to get the original radius look!!... Easy as pie now, all the hard work is done.. ;)...Best to you, til...lat'r...GT

outstanding work

I notice you have rounded the ends of the 'staple'...Where they fit into the grip frame...How do you intend to swage the ends to hold it in the gripframe???

Thanks guys, I sure appreciate all the input and ideas!

The bend could be taken care of either by shimming like Neil suggested, or with the “stop block” or final adjustment step GT is describing. These methods will require some trial and error, I can’t see any other way to determine exactly how much you will need to correct for the springback. Another solution that has crossed my mind is to install some kind of set screw arrangement in the cap, so I can adjust the tension until I find the point where everything ends up straight. Then again, if I can find a better material than the stout and somewhat springy drill rod, I might not have this problem anymore.

The clamp may seem like overkill, but it’s there as an attempt to keep that section straight, and it was also needed to hold the blank centered while I was figuring out the correct cut length for the rod. Once everything works as intended, I have planned to add “something” (haven’t figured out exactly how to do it yet) where I can just drop the blank between two stops that hold it centered. We’ll see what I can come up with, this is actually the first prototype and it already works 99%, so I might just keep the clamp solution. If it ain’t broke, don’t fix it, but now I have plenty of ideas for how to make a new and improved tool once it breaks.

The ends are made with a slight bevel, and there’s good reason for that. If I were to install one of these, I would build yet another fixture that would work as a holder/anvil while I stake the ends to the frame. However, I opted to go with beveled ends to make it easier for other people to install it. My thought is that the bevels make it very easy to put the loop in the frame, straight ends with sharp edges tend to scrape and bind in the holes, and what usually happens is that the piece gets cocked, bent or acts up in general. If you tap it in with a little Loctite it will be secure enough, and my assumption here is that there’s not too much strength needed. I don’t think that anybody would use the lanyard to swing a collectible pistol around, but just to make sure I did a test with a loop installed in a piece of steel together with some red Loctite. It took a large screwdriver to pry it loose, so I would think that it’s an easy DIY solution that’s workable and “strong enough”.

Another idea is to add a bow to the ram, which will push that center area of the loop down while forming.

The rounded grooves are made by drilling through the piece and then milling down to the center of the hole. It's a simple method and doesn't require any exotic tools, but it limits me to straight grooves. I would need a rotary table to make a cut like what you're describing, and I don't have one. On second thought, this might be a very good excuse to buy a rotary table. :D

Is there a market for P-38 lanyard loop staples I am not aware of? If so..how did the originals fall off? Were they staked? Peened? I
don't think the Germans didn't use red Loctite..

Have you tried A2? It hardens more after heat treatment but I believe it to be slightly softer without treatment. It should still have the integrity for a lanyard loop.

I found a source for metric, but I have never used them so cannot vouch.
http://www.flat-stock.com/~store/Mer...ode=PM-A2DRMM3

I get materials from 'inventables' but did not see that they have a2 in metric.
https://www.inventables.com/technolo...-drill-rod-a-2
If you are interested the closest to 3mm are:
7/64 = 2.7781mm
1/8 = 3.1750mm

I don't know if there is much of a market, but I'm not doing it to get rich either. It was more or less one of those "surely enough I can figure out how to make those" kind of projects. But there should be more pistols without lanyard loops than lanyard loops without pistols, as the loops are more easily lost if they ever separate. ;)

They were staked or peened from the factory (have to look closer when I get a chance), but they do obviously come off. They may work loose after while, they may not be peened correctly, could be torn loose by accident, and I know that some were simply removed by owners that didn't like them.

nstallation....
 

Hi Olli, you may want to leave the ends square as they were a press fit into the holes, then slightly expanded to where they were flush to the inside of the frame mag well, i think the popular thought was that, if a few thousands upset will hold tons of force, anything at all would hold a couple of pounds of pistol... best to you, til...lat'r...GT...;)

I'm with you Olle. Lots of times I build something difficult to prove to myself that I can do it and I enjoy trying. When successful, it's not so bad getting compliments from others.