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uncle mike

3 way pass thru

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Hey Gang, I'm hoping to get some input on a project I'm starting soon. I'm sure everyone here knows what a pass thru joint looks like and how to forge it. I'm talking about a simple Split and Drifted round bar with another bar of the same dia. passing thru it @ a 90deg angle. What I'm struggling with is finding ways to pass another bar thru the same intersection @ a 45deg angle using traditional blacksmithing techniques. To be clear, I'm talking about 3 bars total going thru 1 joint. It's not an uncommon design element in grille and gate work. 

Of course I can weld in the third bar, but I like to try to forge my work using traditional methods first and save the contemporary methods for a last resort.  

I'll try to include a pic if I can. Unfortunately I'm better @ Hammer and anvil than I am @ computer and mouse! Heh Heh Heh. :unsure:

 

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Maybe pre slit for the 2nd pass thru so the slit ends up in the first one. Drift it thru at the angle required. Maybe a custom bolster is required here. then fish the other bar  thru the slit.
 Hope that made sense.

Steve

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Not exactly what your describing but maybe an alternative to your design. This is a base of a coat stand I made back in 2010, 3 legs riveted tenon's equally spaced around the center post. It was 1" legs into 1-1/4" round post if I recall.

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Thanks for the input guys, the custom bolster and pre-drifting the second bar is a good idea, but did I mention all 3 bars are the same diameter? I'm going to try to attach a pic or two. 

Jeremy, that coat stand is awesome! Looks pretty substantial as well !

 

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Kinda Looks like it was drilled for the third bar to pass through. 

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1 minute ago, Daswulf said:

Kinda Looks like it was drilled for the third bar to pass through. 

I was just about to say something very similar.

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I guess the pics worked! heh heh  

It's hard to tell but I was wondering about maybe some short, angled tenons for the third member. If I make really good fitting joinery and make the angled bar in two pieces???

I was hoping there was some traditional layout method that I was missing....

These grills are aprox. 100 yrs old and the building is on the historic register, so I'm pretty sure I would catch some flack if I tried to disassemble one!

 

I hate to "kick a dead horse" but, did I mention they were all the same size? If I drill a 3/4" hole thru a 3/4" bar I'll cut it in half.:D  That makes me think of something else though, maybe a dowel right thru the center of the third bar???  Then the hole only needs to be maybe 3/8". 

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5 minutes ago, uncle mike said:

These grills are aprox. 100 yrs old and the building is on the historic register, so I'm pretty sure I would catch some flack if I tried to disassemble one!

 

Meh, no one will notice :-P

Two things that immediately come to my mind are that there's no swelling on bar No.2 and you can't see the setup from behind.

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Sounds like a possible solution. If you got a nice tight fit then maybe drill holes in the main stock to weld the pieces to the connecting through rod. It could be cleaned up easy enough. 

It really looks drilled. Perhaps if it was cleaned up it would show some clues. 

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No swelling on the first pass through member, it's hard to say for sure from the photos but could the 45 degree member have been miter cut and brazed at the joint? There is some build up at the point of contact with the end of the 45 degree member and the scroll work that looks like it could be brazed. Also could be one hundred years of built up gunk. I would think dowel pinning combined with brazing the joint would last for another hundred years and look spot on even if that's not how they did it originally. I hope you work it out, I would love to see your repro when it comes together!

 

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As you already noted, you can not do that joint with 3 members passing through and maintain the integrity of the grill. A close up photo from both sides will reveal that the section at 45 is purely decorative and not structural and was indeed welded on. If brazed or Oxy Acetylene I don't know. Quite possible there is a pin in the joint. The other end that sits between the scrolls is riveted for sure. That grill suffers from chronic rusting in those joints and that confirms to me that it is indeed welded. They have been battling with rust for a while judging from the cold galvo sprayed on.

You could make a joint like that, and if it is one off, and does not need to be perfectly symmetrical like in that grill, you can have your horizontal bar and the 45 bar forged together at 45 and carefully shaped. The vertical bar with the eye, will need to be drifted to accept the joint, opened up at the back and forged back in place. A lot of work for little gain. 

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Greetings All,

          Just an observation .  The scrols are welded I would assume the joint is done likewise.

 

Forge on and make beautiful things 

Jim

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Jim - am I seeing things? - the scrolls are riveted.

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@jeremy k I see the rivet on the virt/horiz members coming into the center of the scroll at right angles but the points of contact with the sides of the 45 degree bars look to have brazing built up. In the last photo one of the questionable, maybe brazed areas looks as if the brazing broke loose in one area. I cant clearly see a rivet head where the scrollwork meets the 45 but that doesn't mean it isn't there!

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Greetings All.

         Just another point . The round bars at the point of intersection are the same diameter. How would one accomplish a drifted hole or a drilled hole with no stock left on the side?

Forge on and make beautiful things 

Jim

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I am 50/50 on the rivet between scroll and diagonal decorative bar. 

100 years ago, blacksmith making that sort of work would frown upon welding and would be masters in riveting at the point of contact going to extreme pain to do so and countersink the rivet and file all evidence of it being there.

Being that the article in the photo is not European, and lacks a bit of detail, I would say it is possible that it is welded at the back. However ... the rust tells a story on older decorative work exposed to the elements. and none of the allegedly welded scrolls have rusted at the point of contact with the diagonal bar.

A third possibility is that they are neither riveted or welded and just sitting pretty. Inf fact I can imagine making the space between both scrolls rather tight, work a bit of a groove on the outside of the scroll and tap the bar between the scrolls in position, nice and snug. A groove in the center of the scroll would make the bar snap in place.  Next you oxy the joint and Bob's your Uncle. :)

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Since there is clearly some cast work behind the grill, is it possible its a  piece supplied as a complete unit, by the alarm bell company? There used to be a lot of very intricate cast work done.  Al

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I also think the 45deg. bars were welded on.  The way the paint is failing in that location is another clue.

If you wanted to do this with all "traditional" joinery, you could split a larger bar into a 4 way intersection, then slit&drift the intersection on the diagonal for the 45deg. pass thru.  It would turn  the swelling of the pass thru onto the diagonal.  

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Only 1 rivet per scroll, nothing but tight fit for the 45° points of contact. If you look close the lump/s you think are brazing, it is the casting "Behind" the grille.

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Wow, we have some activity now! Thank you all for your input! 

So, the grills are definitely forged, not cast.

The job is on a municipal building, so the "buildup" that everyone sees is simply years of bad maintenance and poor prep under a typical slap of Rustoleum. 

I agree that the angled members are not structural. The grilles that I will be reproducing however will be considerably larger, so the joint integrity is fairly important. 

I am going to be building 123 of these grilles, so assembling these joints in a timely manner is fairly important as well!  That being said I am more about delivering a good product than I am about a profitable one! (not very businesslike, I know)

The "rivets"that hold the scrolls are actually large round head screws! I was thinking maybe I would make a slight taper on the ends of those particular bars and drift those swells with a matching taper instead of straight thru. Then the screw would pull everything tight.  The other two intersections of the scrolls are a mystery, however,  I agree with Marc 1, I have seen rivets in some of the damnedest places! (and this is a tight one!) 

As far as the 3 way joints go, I also agree that craftsmen from this era would only weld something as a last resort. However, this project would have been more industrial and less artistic, and it may well be that brazing is the best option??? I have been doing restoration work for 40+ years now and I don't see a lot of brazing in historical work, but I do see it. I would still have to forge the first pass thru properly, and the fit of the diagonal member would have to be done nicely..........B) 

 

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I did not see that detail of the slotted head machine bolt, - I took it for a riveted over tenon. I had to enlarge the picture a little more to see that. With 123 grilles to make  - setting up a milling machine to mill the ends for a tight fit up would be the way to go on the 45º intersection ends. - Good Luck

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10 hours ago, uncle mike said:

I am going to be building 123 of these grilles, so assembling these joints in a timely manner is fairly important as well!  That being said I am more about delivering a good product than I am about a profitable one! (not very businesslike, I know)

123 grills ! now that is some job. How much time do you have and do you work alone?

Personally I don't like the design of the scroll sitting on a round bar. To me it should be the bar passing through the cross member and extend a bit before receiving the scroll on it's end, preferably with an invisible countersunk rivet or screw. 

The diagonals are the least of your problem. Forge the scroll like those in the picture. Notice they are not flat but have a concave surface all around. There is where you diagonal will be held tight. As for the 3 point joint, if you forge/grind a good fit and allow for a good groove for welding, you can rod/mig/ or oxy weld the diagonal at the joint. (I would MIG weld it anyday). File it round and it will look a million dollars better than any brazing that will inevitably rust ... unless you silicon bronze mig it, but why bother? Properly welded that diagonal bar is going nowhere fast and the weld will keep it in place even with a less than perfect fit at the scroll end. 

Make sure you price your work properly and allow for good profit. Nothing wrong with profit!

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Greetings Mike,

       You indeed bit off quite a challenge.  A few interesting points. The outer frame has very sharp edges . Cold rolled?  It also looks like the frame has very sharp corners . Welded ?  Would the stand off bend require bending last after assembly ?  In the past I have done many pass through elements and have used an Allen set screw ( easily disguised ) to lock the element. I only have one picture of a brass ball set with an Allen but you get the idea.  I would enjoy working with you on the build but I’m too far away and getting older. 74 yesterday. 

Forge on and make beautiful things 

Jim

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Could you drift the main bar and then split the back of it. Then attach the two angled bars to each other. Then put the angled one into the opened drift off the main bar and forge weld the drift back together.

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Heh heh, yes Marc, time is always the big part of any "guesstimate"!    I have most of the summer to do this project. At the moment I have 2 helpers in my shop. I may put on another since I have other jobs as well for the summer! 

I always allow for a decent profit, however as anyone with an artistic bent can attest, I almost always use every last second allowed for to make everything "just right". (and then some)

I'm not too worried about the fit. I'll probably set up a mill like Jeremy mentioned. 

Happy birthday Jim! I'm sure I would enjoy working together as well! One of my best friends just turned 80 last week and he forges almost every day! Seems like blacksmithing is good for our health!  Heh heh. :D

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