Straight leg frame question

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wantapanrealbad
Posts: 34
Joined: Wed Jan 11, 2006 2:21 am
Location: Eastern Tennessee

Straight leg frame question

#1

Post by wantapanrealbad » Wed Dec 05, 2007 11:42 am

List,

Does anyone know how far into the neck casting the front downtubes go? I have to replace my neck and the old downtibes are sawed off. I am trying to figure out how long the downtubes were before being sawed short.
Thank You,

Joe



john HD
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#2

Post by john HD » Wed Dec 05, 2007 12:37 pm

does the blue print in the knowledge base show it?

i can't imagine it goes much farther than the bumps in the casting.

john

panhead
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#3

Post by panhead » Wed Dec 05, 2007 12:55 pm

Last edited by panhead on Wed Dec 05, 2007 5:09 pm, edited 1 time in total.

Cotten
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#4

Post by Cotten » Wed Dec 05, 2007 2:58 pm

Mr. P!

That really slowed up my dial-up connection!

Joe asked:
>>Does anyone know how far into the neck casting the front downtubes go?

As far as they can!

You are at a great disadvantage when the tubes have been sawn instead of having the headstock torched away from them. But once you have slugged on extentions, you can easily mock up for your proper rake and alignment.
Note in my attachment that the spine of the frame must also be cut and slugged; the turnbuckle makes it easy to hold the mock up in place while inspecting the alignment with straightedges.

The V-TWIN headstocks that I have installed made it hard to get it wrong.

....Cotten
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panhead
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#5

Post by panhead » Wed Dec 05, 2007 5:11 pm

That really slowed up my dial-up connection!
Sorry, made a link to it! What about a broadband connection?

Guest

#6

Post by Guest » Wed Dec 05, 2007 11:58 pm

Wantapanrealbad: The queation is sort of erelivent. You are going to have to clamp it down in a jig like the one Cotton has shown any way. Once you are compitant that the frame is to factory specs. Measure away.

Ripley/Fla

#7

Post by Ripley/Fla » Thu Dec 06, 2007 1:25 am

Where do you get the head casting? Can this be purchased through the Harley Dealer? The frame jig is an eye opener as a chopped frame could be salvaged. I am blown away at the knowledge on this sight!!!!

Cotten
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#8

Post by Cotten » Thu Dec 06, 2007 3:18 am

Ripley!

I haven't ordered one for a few years, but your local V-TWIN Mfg. (Tedd Cycle) dealer can research it for you. J&P probably offers the same thing by the same part number.

If Tedd's overall quality reputation scares you, then top line forgings are available from http://www.competitiondist.com/ or http://www.raceframe.com.au/index.html.

And we should not call my tooling a "jig", as it has no provisions for fixturing an assembly. It only immobilizes the frame to itself, providing a means to straighten bent bottom members, and to pressure the geometry in various directions.

It is nothing more than a chunk o' I-beam, with cheap auto strut compressors ground to clamp the frame. Also shown in this attachment is a section of drain grating that serves well to clamp and straighten bent members.

The service manual gives excellent directions for measuring the frame's alignment.
The dimensions suggested for the inspection straightedges are not easily found, but with a little math you can correct for using conduit or a fluorescent bulb.
The whole idea is to be able to 'sweep' the length of the headstock straightedge with a straightedge that is parallel to the chassis centerline.
The two straightedges do not touch; you judge the distance between them as the centerline straightedge is moved in an arc.

...Cotten
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Last edited by Cotten on Thu Dec 06, 2007 1:51 pm, edited 1 time in total.

wantapanrealbad
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Location: Eastern Tennessee

#9

Post by wantapanrealbad » Thu Dec 06, 2007 4:34 am

Thanks for all the information gang!

Cotten, can I assume the tubing used for the front downtubes is simply DOM mild steel? (A513 type 5) I found a website where one can order small sections of tubing needed for repairs ....onlinemetals.com, phone 800-704-2157. You can buy it by the foot. I also need to order the 1 inch diameter tube that goes from the headstock back to the spine - can somone tell me what the I.D. is ? I do not have an old one to measure. The website I mentioned has a few different IDs. It probably does't matter, just thought I would go with stock.

Thanks Again,

Joe

Cotten
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#10

Post by Cotten » Thu Dec 06, 2007 2:10 pm

Joe!

I really do not know what the frame material is; Cutting up other frames for repair parts was always easiest.
None are left here to measure for IDs.

Considering that they were often oven-tempered (instilling "memory" as well as springiness), and their resistance to rust is notable, the material must be other than 'mild'.
(I am neither a trained welder, nor metallurgist.)

(Beware of modern frames from (at least) the mid 80's on....they are made of mud!)

....Cotten

fourthgear
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#11

Post by fourthgear » Wed Dec 12, 2007 3:09 pm

Also having a set up like Cotten's , keeps ever thing straight after welding . It can be a eye opener when your measurements get kinda funky after welding with out some kid of jig fixture to hold them to your spec's.

Cotten
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#12

Post by Cotten » Wed Dec 12, 2007 3:32 pm

At risk of repeating myself...

The tooling I have shown is not a 'jig' or fixture for "keeping things straight'.
(I apologize for using the term in the photo label, but it is hard to keep them under eight letters.)

It does not matter how firmly you hold steel when it is welded, it moves on a molecular level.
Frames must be massaged to 'straight' after welding, and that is what my primitive devices allow.

Most frames have "memory" that results from their tempering and stress-relieving processes after the original weld construction. For that grace alone, re-straightening of bent original frames is relatively easy as long as you do not apply heat.

Once again, most of what is shown in my first attachment is nothing more than inspection straight-edges.

...Cotten

Commander47
Posts: 12
Joined: Thu Aug 16, 2007 1:48 am

#13

Post by Commander47 » Mon Dec 17, 2007 1:05 am

dscf0006zw6.jpg
I have done a couple of frames over the years and have never used a real jig.

In the pictures is a 51 wishbone frame i just restored using a neck and rear wheel castings from V-Twin. I got the sidecar loops from a guy on Ebay.

The rest I did myself. I followed the instructions on how the frame lines up exactly. Like Cotton says, holding it in place after careful measuring is key.

What I do is tack weld everything in place. Then I check, and recheck alignment and Level the rear castings and sidecar loops.

Those rear castings are a bit tricky because the distance between them has to be correct. They will want to V out on you.

The neck is actually pretty easy. Line it up, make it level, check the distance from the rear mount...and tack it up.

The sidecar loops are a bit tricky. The wishbone curves and the correct alignment take time to get right. I had to space the right side a little higher than the left and fill in the space with weld.

The castings and loops have holes like the original to allow you to adjust before final filling and weld.

I weld one side at a time and try not to heat anyplace other than the where I'm welding.

Some may not agree with this, but I also added slugs into the rear castings and welded it all up so that the slugs go above any heated area for added support.

Take your time....line it up......and all should be fine.
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Guest

#14

Post by Guest » Mon Dec 17, 2007 1:25 am

Thanks Commander! Great pics. Since you replaced the axle holders, I don't supppose you have whats left of an exhaust hangar lug from a right side casting would you? Mine has been sawed off.

Joe

Commander47
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Joined: Thu Aug 16, 2007 1:48 am

#15

Post by Commander47 » Mon Dec 17, 2007 11:04 pm

Image

I cut the castings off in such a way as to preserve the original tubing.

All of the castings had been "sanitized" for a bobber/chopper at some point.

There isn't really much left.

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