Mac's blog

[izirath]

Wouldn't it be perfect to braze them together? Flat surfaces, clean. You lacked a heat source for that?

[Zanetto]

Mac,
Be sure to practice on some scrap before trying to weld up your knuckle form. Also, get some new, dry rods. And don't forget to grind some small levels where you plan on welding.

Rob

[Chris Gilman]

Mac,
Would it be worth making a rectangular sheet metal "cup" and square up the bottom of the blocks and set them into the cup. You wouldn't need to weld such heavy material and the side would be flat for clamping. Then you could remove knuckles as needed. If needed, you could tack the side of each block to the cup. Alternatively, cut a groove down the center bottom and put them on an inverted "T". once clamped in the vise, the blocks would pinch the T and not move. Again, giving you the option to adjust or replace the individual knuckles.

[Mac]

Wouldn't it be perfect to braze them together? Flat surfaces, clean. You lacked a heat source for that?

Braze, or silver solder would be an option, but I'm not sure I can get the whole think hot enough with the torch I have. If I try it and fail, I'll have to clean it up in order to fall back to the stick weld, and that seem like a disagreeable prospect.

Mac

[Mac]

Mac,
Be sure to practice on some scrap before trying to weld up your knuckle form. Also, get some new, dry rods. And don't forget to grind some small levels where you plan on welding.

Rob

These are 6013 rods. From what I have read, they are not so sensitive to humidity as rods in the 7000 designations. I was hoping that meant that I didn't need to get fresh ones. Now I am worried.

I guess I'll see how the tests go and decide from there if I need to find new ones.

If you read this during your lunch break, and can post from you phone.... What amperage setting would you suggest?

Mac

[Mac]

Mac,
Would it be worth making a rectangular sheet metal "cup" and square up the bottom of the blocks and set them into the cup. You wouldn't need to weld such heavy material and the side would be flat for clamping. Then you could remove knuckles as needed. If needed, you could tack the side of each block to the cup. Alternatively, cut a groove down the center bottom and put them on an inverted "T". once clamped in the vise, the blocks would pinch the T and not move. Again, giving you the option to adjust or replace the individual knuckles.

These are both good ideas, but I think I need a tool more than an tool system right now. I hope that does not turn out to be short sighted

Mac

[Mac]

I've swept the floor, moved some stuff around, and set up a sort of impromptu welding table.

When I plug the welder in, and flip the on/off switch, I get a 60hz hum, but no noise or air flow from the cooling fan. So, I guess I'll be taking the back off and looking at that fan.

Yes, I have unplugged the welder from the wall.

Mac

[Mac]

The cooling fan motor is definitely shot...



...and this is why I think so.



I gave the fan blade a tug to see if I could get it off the shaft so that I had better access to the mounting screws, and the whole damned shaft pulled easily out of the motor.

I have located what might be a suitable replacement here. I guess I'll call them and see if I can verify whether or not it will work.

Mac

[Mac]

I've done a little digging around. The motor I linked to above won't do. It's 120v and it looks like the old buzz box needs a 240v motor. The one that Lincoln sells is called M13539-1, and it goes for about $90. That is, of course, not exactly what I wanted to hear. At that price, I might be better off just getting a new welder.

Mac

[wcallen]

If you are going to think about a new welder anyway....

Could you just point a normal fan at the thing blowing the air in the same direction and get some welding done? As long as it moves the same (or more) air in the same direction, it should be as safe as the internal fan.

Wade

[Christian Wiedner]

Perhaps you dont even need the fan. In my tig welder the fan starts to run only if I weld with high ampere for a longer time. So if you only do some short welds and let the welder cool down it should be possible...

[Mac]

OK.... this has been a sort of a bust. It turns out that me never-been-used autodarkening welding hood from Horrible Freight does not work. It's it has a photocell to keep it charged from the welding arc. I have had it sitting in direct sunlight for six hours, and it has fail to darken when subjected to a spark from a torch lighter. That's the test that people seem to use as a sort of standard.

I've broken down and ordered a new fan motor, but that won't be here for a few days. In the mean time, I guess I'll try silver soldering the tool.

Mac

[Mac]

It turns out that there are two important things to know about "solar powered" auto darkening welding lenses....

--they have two 3v coin cells permanently installed within, and when they are dead, it won't work.
--replacements are available cheaply on Ebay.

I've ordered up a replacement, but in the mean time, I have ventured into the "valley or no user serviceable parts within" and replaced the dead coin sells in my lens. I followed a variant of the plan in this You tube video. As far as I can tell, it's working. When I make a spark with a torch lighter, the lens goes dark.

Mac

[Zanetto]

Mac,
Sorry for the late reply. Your amperage setting depends on the thickness of the metal you are welding and the diameter of the rod you are using. Do you have any drops of your parent stock to test weld on? Also, be careful about getting weld splatter on your nicely machined knuckle surfaces. I would not stick weld these together, but I understand your options are limited. Perhaps silver brazing is the way to go.

Rob

[Rene K.]

Hi Mac,

why not screw them together ? Or is there no metal-workshop in your area that can weld the pieces for you ? The welding would be a thing of 10 minutes.

[Scott]

Good point on the weld spatter. I use anti-spatter spray, but in a pinch I have used Pam, to help keep the spatter from sticking.

- Scott

[Mac]

I'm going to try to silver solder them together, and that will require some means of keeping the parts from shifting. The obvious thing is binding wire, but it's clear that the sloping sides of the assembly will allow the wire to slide down and loosen. So, I've made notches for the wire.



Of course, the center two knuckles are still free to slide out of place.



To prevent this, I have drilled holes between adjacent parts to accept 1/8" rods to act as keys.



That went OK, but the holes did require a bit of attention with a round file. I also had a bit of misalignment of the parts during the drilling, and I have refiled a couple of the knuckle faces to correct that.



I'll get all this degreased, fluxed, and bound with wire this afternoon.

Mac

[Woodswork Armory]

Good luck to you Mac, that was a pretty good idea of holding the middle pieces together, i'll have to try it some time

[James Arlen Gillaspie]

I just forge the knuckles one at a time. It will be interesting to see if this form offers a genuine advantage.

[Mac]

The set up.



The flux, and the solder.



Alea iacta est



I'll let it cool for a half hour or so and see how I did.

Mac

[Mac]

I just forge the knuckles one at a time. It will be interesting to see if this form offers a genuine advantage.

That's certainly what I normally do. The problem is; if I do it cold, it hurts my hand, and if I do it hot, I have trouble holding onto the work.

I thought this was going to be an easy experiment, but it's beginning to look like "the congress of the goat"


Mac

[Mac]

Hi Mac,

why not screw them together ?

I had not considered that..... I'll keep it in mind.

Or is there no metal-workshop in your area that can weld the pieces for you ? The welding would be a thing of 10 minutes.

I'd rather screw up a project myself than to pay someone else to screw it up.

Mac

[Mac]

Mac,
Sorry for the late reply. Your amperage setting depends on the thickness of the metal you are welding and the diameter of the rod you are using. Do you have any drops of your parent stock to test weld on? Also, be careful about getting weld splatter on your nicely machined knuckle surfaces. I would not stick weld these together, but I understand your options are limited.

I had not even considered the weld spatter! I suppose if it came to that, it would come off with a little filing. No?

In any case, the stick welding is on hold till I get a new fan for the welder... and a new autodarkening lens.... oh and I just ordered a suitable extension cord, so I don't have to reconfigure that whole damned shop. Who would have thought there were so many ducks to line up?

Perhaps silver brazing is the way to go.

Rob

I hope so!

Mac

[Mac]

A bit of preliminary cleanup shows that I have brass all the way around. I hope that we can presume that means there's brass all the way through as well.



My set up for the soldering had a couple of small problems. While the key rods prevented any motion in one axis, nothing really prevented it in the other. This lead to two issues. The first is that the rods themselves slipped down until they made contact with the firebrick. I sort of expected that, and its effect is only an aesthetic one. The second is that the whole assembly sagged a bit in the unsupported axis, so that each knuckle ended up displaced from its neighbor by a few thousandths. I didn't count on that one, but it dosn't have much effect on the tool. There will be a bit more clean up to get the sides parallel, and the tool will be a little narrower than I expected.


Tomorrow I'll drill and tap a couple of holes to mount the work piece, and see if the concept works.

Mac

[Indianer]

The set up.

Excuse me Mac, would you just briefly explain what we see in this picture? Apart form the tool, of course. What is that white grease between the pieces? Is the solder already squeezed in there at this point? And why do you heat it all up afterwards?

feeling like the dunce in the class

Best, Indi

[Mac]

What is that white grease between the pieces? Is the solder already squeezed in there at this point? And why do you heat it all up afterwards?

The white stuff is the flux, which covers all the surfaces that I want the solder to stick to. The work is then heated to redness with a torch and the solder is applied to the joints. If all goes well, the solder is pulled in by capillary action.

Mac

[Indianer]

Thank you Mac! Can´t wait for the result.

[Mac]

I drilled the ends of the tool and started the tapping (1/4-20) on the drill press.




The generous 5" quill travel on this otherwise undistinguished Enco makes that possible.



If I were going to make the knuckle the way I usually do, this would be the size of my starting template.



But it does not compare favorably with the tool. I'm sure there will be a shortfall at the ends, but I don't know how much.



The only way to tell is to try. I added a likely amount to the ends and cut it out of .042" stock.



What I usually do for knuckle like this is to beat up four big round bosses and then raise them back down to points. I figured that the procedure here would be similar in that regard, so knocked up the bosses with these hammers and this brutal looking dishing tool (an iron pipe adapter bushing).



Offering the work up to the tool, reveals that the shortfall is about 3/8" on each end.



The next template was 3/4" longer in the middle.



With the new plate bossed up and screw down, I started in with the torch in one hand and a hammer in the other.



This is where I began to have trouble, but I figured I would forge ahead and see what other troubles ensued.

It looks like the problems are these....

--I let the starting piece get twisted into a sort of "S" shape by not locking the work down against the points of the tool soon enough
--I worked the piece back and forth against the points while there was too much slack, and that tore a hole over the first and last one.
--I didn't get the ends shrunk sown soon enough, and that let the work which was already set against the tool rise up.
--I didn't make the starting piece wide enough.




Some of the things I need to change can be inferred from the list above, but there may be other things that need to be done differently as well. I'm questioning the wisdom of starting with bosses, and might do something different next time.


So... I'm going to let this percolate a bit before trying again.

Mac

[Keegan Ingrassia]

I wonder...would it do better to fix one side to your form, then work your way across? Up one knuckle, down to the valley, and repeat. You would be taking up the slack, there would be less stress in the points to tear, and you could hopefully correct any lateral wandering before it became an S-shape. Just a thought.

[Indianer]

Add a little prong to one side of the tool, permit the rider a longer allowance on one side to accommodate a hole drilled through for catching the pin?

EDIT: Oh, and can you preshape the blank with aluminum foil? Take the pattern directly from that? Might help with width...and would be interesting to see

[Mac]

I wonder...would it do better to fix one side to your form, then work your way across? Up one knuckle, down to the valley, and repeat. You would be taking up the slack, there would be less stress in the points to tear, and you could hopefully correct any lateral wandering before it became an S-shape. Just a thought.

I think it might be better to take the "slack" out of the two ends and work towards the center.

Part of me says to try to wire down the valleys to keep them form rising up when they get a chance. That would be difficult while the tool is in the vise, though... I would have to add some spacers to the sides for the vise to grab. That would let me run wires without taking the whole (hot) think out of the vise.

Then again, this whole idea might be flawed.

I'll try a couple more things tomorrow.

Mac

[Mac]

I had another go at this today, but didn't get very far before I gave up.


The process that I envisioned contains two essential flaws...

--Getting from an essentially flat piece to the desired knuckle shape requires too much shaping to be done in one step. It's too difficult to raise the work down "over the air" without getting wrinkles.
--The pointy little nipples are too sharp to serve as mandrels, especially early in the process.

It might be possible to rough out the volume of the knuckles by raising over an anvil horn, and then finish up the shape on a mandrel, but even there, I think the nipples would worry their way through the plate.

A better approach would be to work up the knuckles by hand (or however) to a depth that is sufficient to produce the desired overall shape, and then work the very points down hot with no support. A mandrel like the one I made, but without the nipples might well serve.

It's easy to see where that line is headed, but I will do some more experiments before I just grind the nipples off.

Mac

[Aussie Yeoman]

...I will do some more experiments before I just grind the nipples off.

Mac

I nominate this for quote of 2018.

[James Arlen Gillaspie]

Getting back to one knuckle at a time, seeing as the knuckle blank is a strip, more or less, why not extend both ends beyond what you could possibly need and then rivet handles to them, and trim the excess off later? That way you could hot forge to your heart's content.

[Sean Powell]

I had another go at this today, but didn't get very far before I gave up.

The process that I envisioned contains two essential flaws...

--Getting from an essentially flat piece to the desired knuckle shape requires too much shaping to be done in one step. It's too difficult to raise the work down "over the air" without getting wrinkles.
--The pointy little nipples are too sharp to serve as mandrels, especially early in the process.

Mac

I was thinking the same thing as I read the post this morning. In the industry that deep of a draw would be handled with a progressive die. Much liked you dished 4 domes to start there would be another middle process of stretching the valleys down because that's a larger chunk of material and will require more force than raising the tips.

Question: would it not make more sense to process the steps as 4-domes then the valleys between the domes then collapse the domes into cones THEN create the sharp tips? I've got to think that the tips could be done over a single 'nipple' stake that is moved from knuckle to knuckle... or is that too much hot-work close to your fingers?

Sean