Frame Restoration

[Steve Little]

Now that the spears have been brought back into correct alignment, I will ease my way into addressing the lack of forward sweep in the spears.

The picture below, shows the side view of the spears on my spare 1936-1940 fork.
It has been tampered with, or traumatised at some time in its past life.
Instead of a forward sweep, this fork actually has a negative sweep.
Straighten 36-40 springer 002.JPG
This next picture shows the height gauge set at the correct height of an inline axle.
It looks to be about 1/8” negative

Straighten 36-40 springer 003.JPG
I am going to use Kyle’s estimate of the forward sweep axle measurement, as I have no other information to use at this time.
I am getting up on my soap box now.
If any of you (100’s of peepers) have a good condition forward sweep fork, laying around, it would be very helpful if you could add some input on the measurement…or confirm Kyle’s measurement.
Keep in mind that this is probably the most information that has ever been written about these forks, so have some input.
When I get the time/energy to take the springer off my 37, I will measure it and add that to Kyle’s measurement.
The more measurement that we can garnish, the more accurate our accrued information can be.
There are an awful lot of these 1936-40 springers that have been straightened by a couple of very well known HD restorers in the US over the years, because they didn’t know any better.

Firstly, I established the measurement of the centre of the spindle by placing the height gauge on top of the rod. See picture. Then subtract half of the round bar to calculate the centre of the spindle.
Straighten 36-40 springer 005.JPG
Then I added Kyle’s measurement to the centre height of the spindle.
Then set the height gauge to that measurement.

The height gauge pointer indicates where the centre of the axle hole should be on a forward sweep fork.
The next step is to put the forward sweep back in the spears.

Straighten 36-40 springer 006.JPG
I have designed a couple more fixtures for this next operation.
The ram will be placed under the end of the spears to press them up.
I do not want to put all this upward pressure on the neck spindle, so I have drawn up some supports that will be bolted to the jig and hook over the top of the spears.
I will be able to support the top of the spear at any point along the jig and achieve a forming action at that point.
It may be a week before I can do any more work on the leg.
I ordered the steel yesterday.
I am having the plates profile cut and surface ground to make them look pretty and also, cut down on some of the machining time.
I’m getting sick of my own diatrab, so if anyone would like to chime in to add your experience of fork adjustment I would be happy to read it.
I will post more pictures when the fixtures are ready

[poorbiker]

Steve,
I have wondered more than a time or two if there is a calculation for how much over bend is necessary to straighten a bow or bend in various metals, cold. I once tried to straighten a 1/2" x 12" x 4` piece of cold roll that had a 1/16" bow in the middle of the plate. It finally took a little over 6" to remove the bow. I concluded it had to be the quickness with which the opposite force is applied (without heat) to effect change in the metal structures memory, I think requiring less over bending, travel. But I suppose that would be just another form of heat generated by quickly bending it, more of a quick hydraulic pressing. But I could be full of crap also.

[Steve Little]

As I have written, I had very little first hand knowledge of working with Chrome Moly.
In an earlier post, I suggested that I was going to get a springer blasted so I could apply heat to the spears to aid in the straightening process.

A lot of people use the AMCA forum as a base for working on their projects and I must clear up that incorrect comment.
After I made this jig and set the first springer in the attachment, I felt under prepared with information to proceed with the job.
After my initial appeal for “springer straightening” information was met with deafening silence, I started a hunt for information in other avenues.

A reply from HD confirmed that the springers were straightened on the factory frame tables. And that Harley Davidson booklets that went with the HD straightening tables, are out in the world somewhere.

Also, I needed more information on the correct procedure for straightening Chrome Moly.
Ric, kindly advised me that it was going to be like herding a bunch of cats.
I only have one cat, and when I had a couple of attempts at herding him, he just sat down and looked away, indifferently.

I trawled through 5 or 6 forums that came up with a google search of “working with Chrome moly”.
There is plenty of information on Tig welding, brazing and tube benders for forming Chrome Moly, but I could not find one single reference to straightening a slightly bent tube.
I decided to resort to a phone call to a drag racing car manufacturer here in Australia for some first hand info. He advised me that when the nitro cars get a bout of shake, the frames get bent, (hate to think what it does to their bodies). So he does a lot of straightening.
He stressed that under no circumstance should we apply heat to Chrome moly to straighten a mis-alignment. Quote: “Heat will anneal the Chrome moly which is not the desired result. All adjustments must be done cold to maintain rigidity of the metal”
So, in conclusion, I wish to offer an apology for any bum steer I led anyone on. And to my cat for upsetting him.

[Steve Little]

Alhoa Ric. Thanks for the advice, and there was some of that going on.
You might have noticed from the pictures that originaly started work on another springer but switched to this earlier springer. A friend of mine wanted to repaint all the tinware on my 37 knuckle. So I let him and it looks so beautiful and shiny with this new paint job. But there is a draw back to putting lovely glossy paintwork on a bike that has been assembled for a while.... the rest of the bike now looks tardy. So now he wants to paint the springer and we are running out of good painting days as we scream toward winter over here. I dont have the energy to pull the whole front end off the bike at the moment, so I thought I would straighten this springer and give it to him for painting.

Back into the picture process:
I pressed it 1" past the measurment I wanted.... and supprisingly it made no difference
Straighten 36-40 springer 017.JPG
Straighten 36-40 springer 019.JPG
It eneded up moving at 1 3/8" (35mm) past the measurement I wanted.
If you are going to use my expieriece as a manual for your springer, I suggest a carefull approach like I have done. Dont assume that 1 3/8" will be right for your springer.

After releasing the ram and then measuring it, check out the vernia reading.
If there was such a thing as shed cam, you would have seen me do a little jig.... and then a a calming moment and then an air punch.

[ricmoran]

Steve, your on the right track, I have to say I'll bet your butt is puckering while your bending. Do you have another springer knocking about that is beyond help that possibly you could experiment with? That might help get to the correct over bend factor to arrive at the final set you seek.

[Steve Little]

I decided to press it 3/4" passed the measurement I wanted.
Straighten 36-40 springer 016.JPG
Nope!! It just followed the ram back home.

Ok. I,m Freakin out... but I,m going to press it 1" passed the measurement I want.

I'm thinking...what the hell is going to happen.
This is my part, but I dont want to ruin it.
Its a genuine 1936-1940 keyhole springer.
They stopped making them you know!!

[Steve Little]

The right side spear is just short of 1/4" out of correct alingment.
I have no idea how far I have to press this spear, to allow for spring in the metal and get a change in measurement.
I started by pressing a 1/4" past the measurement I wanted. Thats about 1/2" of spear movement. I can tell you I was nervouse!!!

Nope! It didn't move a jot.
It just followed the ram home like a dull eyed cow, when I backed the ram off.

[Steve Little]

The bow came out pretty well and the measurement HD has listed is 3.703".
Although the vernia readout has a bit of flash reflection it reads 3.701.
I'm thinking I will leave it at that for the moment and move over to the other leg
Straighten 36-40 springer 011.JPG

When I set the vernia to the HD measurement of 3.307" and put it on the right side, you can see how much the spear has to be pressed toward the centre line to come into alignment

[Steve Little]

I have been a little bit hesitant on how to go about straightening these spears.
I have only done a small amount of work with Chrome molybdenum about 6 or 7 years ago and I didn’t enjoy it very much.
This over head shot of the left leg shows that it has a bow in the centre.
Straighten 36-40 springer 001.JPG
I decided to start by straightening this spear first.
I placed a rule on the inside of the spear to determine where the bend starts and ends.
And marked couple of lines to help during the setup
Straighten 36-40 springer 005.JPG
My first go at pressing the spear failed. I used high density rubber, thinking that it would be strong enough to push the tube but not dent it. Wrong. Not enough body in the rubber.
Straighten 36-40 springer 008.JPG
Hunted around the workshop looking for some nylon but could not locate it so down the Super market and bought a $5 2 pack speacial bread board and cut it to the size I wanted.
Now we are cooking

[Steve Little]

Thanks for clearing that up Ric.
When I fly to LA I try to resist looking at the flight path screen for as long as I can.
Usually I watch a movie, do a couple of laps around the craft, watch another movie, couple more laps, sleep, listen to music then...I gotta look at the flight path Woohoo!! we are past Hawaii. I thought it was 6 hrs but I just checked the Qantas flight time for Syd to Hon....9 hours 45 minutes
(Flew Hawaiian Air and it took 11 hours to get to Sydney) Qantas must fly faster in those new A380's or Hawaiian air must be "takin it easy bro".

[ricmoran]

[QUOTE=Steve Little;130773]

Not looking forward to boxing up the frame I have for it's overseas journey to the mainland US, as at this point there is no other option.

Hi Ric.
I flew to Hawaii 2 years ago to visit a friend on Kaui ( not sure if that is spelled correctly) and it took 6 hours flying to get there. It generally takes 15 hours to fly direct to LAX from here. Does that mean you are closer to me than mainland US?

Steve, we did a tour of the east coast of Australia back in 2005. Flew Hawaiian Air and it took 11 hours to get to Sydney. Form Honolulu to Los Angeles is a 5.5 to 6 hour flight depending on headwinds. We are about 2,600 miles from LA where Sydney is just over 5,000 miles so it is just about twice the distance.

[Steve Little]

Hey Kyle. When I had a look through my springers I realised that this has the same mis-treatment as yours. This was a "foreward sweep" springer (1936-1940) that has had the foreward sweep taken out of it.
The 1936-1940 springers can be identified by the keyway that is machined into the bottom of the steering dampner hole "as seen on the left hand side of the hole".
I might get this springer blasted before working on it, as I will have to use heat on the spears to help in the re-forming of the foreward sweep.
I think that quite a few of these foreward sweep springers have been straightened to the 41-46 workshop manual description.
The piece of french chalk sitting on the spear of the springer, shows where the alteration was made. There is a slight bump in the spear at this point.

[Steve Little]

Hi. Apologies for the delay.
I was not satisfied with the initial design of the spindle fixture.
My first design did not hold the neck spindle on a positive, centreline, alignment with the jig, and instead, allowed the springer to self align.
I changed the design of the fixture to hold the spindle on the centreline of the jig (effectively, like it would be held in the motorcycle frame) and I am happier with this higher level of thinking.
This design looks to be robust enough to withstand the rigors of straightening the spears of the springer.
If it is not, maybe I can fit a maginfied lense in each end, and try to accelerate some light particles.
On second thought, maybe not. My shed might implode and leave me standing there with a puzzled look on my smoke stained face, and a few wisps of smoke rising from my hair.

[Steve Little]

[QUOTE=ricmoran;130752]

Not looking forward to boxing up the frame I have for it's overseas journey to the mainland US, as at this point there is no other option.

Hi Ric.
I flew to Hawaii 2 years ago to visit a friend on Kaui ( not sure if that is spelled correctly) and it took 6 hours flying to get there. It generally takes 15 hours to fly direct to LAX from here. Does that mean you are closer to me than mainland US?

[ricmoran]

Fantastic Steve and your reply was not too long.

Impressive history and experience you have and it shows in what you do in the images.

If I were as accomplished at this as you are, I would do exactly the same. Your in a business and any chance to let folks know what it is all about is excellent & smart marketing.

One Oahu, the are 2 shops who build frames, side by side. These are just down the street from me.

I stopped to discuss needed frame work at both shops.

Their answers were very telling as they answered with body language. Crossed arms, a step back and no answer. Discussed with them proper OEM frame repair and they advised we only build custom frames, nothing like what you need. I asked about their jigs and they advised they built them as well. I have to believe though they did not go to the extent you did and that extent reflects in what happens at the close of work in restoration.....correctness of frame geometry for trueness when run on the road as well as providing clients with the most important part of this, a safe frame that a client needs not worry about having issues with.

Not looking forward to boxing up the frame I have for it's overseas journey to the mainland US, as at this point there is no other option.

Purchasing a jig would be a wise investment, but only if I were in a market where there is demand for services as you perform...this all states to me another good reason to relocate!

Thanks for your reply.