The making of a 1936 Knucklehead springer front end

[Jerry Wieland]

The brake anchor needs to have the weld disappear and be brazed. I have not had much luck trying to braze with a torch what HD brazed with a furnace. It is hard to get enough heat into the fork to get the braze to fuse without getting too much heat. So what I do is dress the weld until it no longer looks like a weld. I have had a fair amount of practice doing this because over the years I have fixed quite a few Indian frames that had 'slipped joints'. The late Indian frames were very poorly brazed and it is not uncommon to have a joint pull apart. I would remove the tube and then because I no luck with brazing the big bulky Indian castings, I would weld them and then have to dress them back to appear not welded.

Before



After

[Jerry Wieland]

I also needed to slim down the fender tabs so I made a patter from another front end,



I then laid it on the springer fender tab and carefully outlined it with a marker and started carefully removing metal until I was happy with result.

[duffeycycles]

Jerry ,on both my Cannon and my Nikon,Macro[close up] is a flower..on Nikon SLR it's on the dial on top of camera,
on point and shoot cannon its on the back
Flash on off is a lighting bolt..same thing,on top SLR -on back on point and shoot
On SLR you rotate to the lightning bolt ,on point and shoot you press it and it will say flash on ,press again it will say flash off,,,wait until it's done before chainging to Macro or it will turn the flash back on
hope this helps .Roger

[Chris Haynes]

Use a Rosebud tip for best results when brazing.

[Jerry Wieland]

Use a Rosebud tip for best results when brazing.

Thanks for the advice Chris

[koanes]

I looked at the two 36-E37 forks I have and they both have the dents, obviously part of the manufacturing process. One of them came with a motorless 37 basket case I bought, the other with a parts pile, so no history. Jerry, I think you better push some dents in the fork to finish the job. (Insert face with smile)

[Steve Little]

Robbie This is the first that I had heard of the dimples and I do not know what to make of it. I have no doubt they are original but the springer on my original 36EL2025 does not have them or do any of the other 4 early springers that I own. Secondly the obvious question is why. What is the reason for them. I cannot believe that a messed up stamping die would be allowed to run that long with such an obvious defect. Why only on one leg - I assume that both legs would have been stamped in the same die. Especially on a bike that they (HD) were apprehensive about releasing in the first place.


Jerry

Hi Jerry
I am enjoying you'r picture sequence of work.

A possible scenario for the dented leg. As follows:
The forward sweep of the 1936-1940 springer legs, would mean that there would have been separate forge plate sets for left and right sides.

Traditionally, *forge plates (when first manufactured), are hand polished with fine emery paper in the indented shape, to the smoothest possible finish.*

A dent in one of the legs would mean that something has stuck to the surface of the indented shape of one of the die sets.*
A possible scenario could be that the forge operators let the plates get too hot during production of the legs, and some red hot scale has annealed itself to the surface of one of the die sets.*
If this happened part way through the production of the run, it would account for some having the dent, and some not.
Supposition only!!*
Regards Steve

[MMasa]

We're these legs originally roll forged?
Mark

[Jerry Wieland]

We're these legs originally roll forged?
Mark

Mark I do not know what you mean by 'roll forged' but I am absolutely convinced that the legs started out with the profile of the up tubes. They then went inside with a "swedging' tool and spin expanded the leg until it looked like a lamp post. When this was done it was put into a stamping fixture and "flattened' and given the offset bend. I think that the swedging had a tool hardening effect on the leg and added to the strength of it as a result. The 'porkchop" piece as I have heard it called added even more strength where it was needed most.

This process was a fairly common technique in the brass lamp industry that abounded in the 1920's and 30's and I think HD used it to make their frontends.

I might be wrong but that is my story and I am sticking to it.

Jerry

[Chris Haynes]

My '36 fork has no dimples or dents.

[Steve Little]

The original sales booklet that I have for 1937 has a picture of the springer with wording that says "Chrome moli tube front forks for extra strength"
I am at my beach house, so I can't scan and share at the moment.
Chris, have you heard of this phenomena prior to this thread?
They still make springer front forks. It would be great to know how they form the legs.
I think the rear legs are the most interesting/complicated part that HD made.

[Jon Louis]

Definitely a dimple on my 36' springer rear legs ( both sides ). JL
No real history to pass on. Bought 'em offn Ebay yearz an yearz ago. JL

[duffeycycles]

[Chris Haynes]

[Jerry Wieland]

OK guys, I dug out the last early springer leg that I think I have. It is a little rusty but actually a pretty nice front end except some Bozo back in the past did a poor job of straightening the lower legs. This is the 5th one I have looked at and not one of the first 4 had the little dent but guess what.



At first glance this one does not look like it has a dent either but I could fell something ever so slightly with my fingers. Then when you shut off the flash and get the natural light just right - presto. This is the left leg.



Right leg.



So both legs on this springer show at least some distortion. The pictures are a bit fuzzy because it took my camera about 10 seconds to intake enough light to get a decent picture - I guess I am shakier than I thought.

OK after further analysis these dents are less severe than what I was anticipating. 2 of the other 4 early legs that I looked were once chromed and it is quite possible that dents could have been polished out during the chroming but that still leaves 2 painted early springers with absolutely no dents.

We have a sonar device at work for measuring wall thickness on pipes that we use 2 twice a year to measure inside erosion on critical cooling pipes. I think it just found another job - measuring wall thickness on those 2 chromed springer legs. I'll report back when I have any results.

Jerry