Straight leg frame question
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Straight leg frame question
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
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
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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
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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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
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.
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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, 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
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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
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
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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
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
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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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