On hold 2nd guessing

[Zandoz]

Because of my health issues, I've put the next step in my project (having the frame built) on hold. The frame I was going with would be a lot of compromises from what I had originally envisioned. So since I have nothing better to do, I decided to fire up DraftSight and see if starting from scratch I could come up with a frame layout that would be less of a compromise.

To ease getting in & out with my mobility issues, in the door area I need the top of the frame rails to be at 12" or less high. On the compromised design I was going to go with, the best I could do is around 15"...requiring an automated air ride suspension on the rear to make the car "kneel" while getting in & out. The limiting factor being the angle and height of the rear kickup. Most of the T-Bucket frames I've seen have kickups at around 7"-10" at 45° or 60°. The compromised design I was going with would be 7" at 45°.

The design I'm playing with now would have a kickup around 10"-11" at 80°. I have seen rat rod frames with the kickup at or near vertical, and over a foot or more high...but rat rods don't have a popular rep for sound engineering. Given that the car I'm planning will be short wheelbase, light weight, and low power...would the 11"/80° combo require additional bracing and/or gusseting?

 

[HenrysT]

The angle should not matter, match the angle to the back of your body. As long as your welds are sound, you will be good. Some do a straight miter cut, some leave one side of the splice square and cope the mating piece to fit ( like a "z" type weld joint), Either way I would put a splice plate inside the tubing (both sides) so you don't have to worry about burn through.

 

[old round fart]

I was working on a very wide door for me to get in a bucket. I have put it on the back burner but if you want to look at what I'm doing and if it works for you I can do 2 at a time almost as fast. PM me if you want to talk about it.

 

[Zandoz]

The angle should not matter, match the angle to the back of your body. As long as your welds are sound, you will be good. Some do a straight miter cut, some leave one side of the splice square and cope the mating piece to fit ( like a "z" type weld joint), Either way I would put a splice plate inside the tubing (both sides) so you don't have to worry about burn through.

In this case, there is no matching the body angle. The previous owner of the body cut out around 2/3s of the back of the body, for channeling the back of the body over the kickup. Since I'm doing a '50s short wheelbase bobtail style car, I'll be channeling over the kickup to.

Would doing fishplates on the outsides of the miter welds be an alternative to the inside splice plates?

 

[Zandoz]

I was working on a very wide door for me to get in a bucket. I have put it on the back burner but if you want to look at what I'm doing and if it works for you I can do 2 at a time almost as fast. PM me if you want to talk about it.

The body I have has a 3"-4" widened door on the passenger side. For the driver side I've been planning on a door as wide as I can get and still clear the tire....done similar to the doors on the silver car that RPM has as his avatar.

 

[RPM]

@Francis Blake has that silver car now and could possibly get some measurements for you.

 

[Zandoz]

@Francis Blake has that silver car now and could possibly get some measurements for you.

Thanks! I'm a long way from actually doing anything, but if/when the time comes I'll contact him.

 

[HenrysT]

Would doing fishplates on the outsides of the miter welds be an alternative to the inside splice plates?

That's above my pay grade to answer that question, and I hate to generalize an assume, but I believe most frames are just plain butt welded and they (the frames) seem to survive. To me, anything you do to get an excellent weld on the base metal would be first priority, if you want to add a gusset later, that would be better!

 

[old round fart]

I usually don't splice plate my welds. I just do a nice bevel and leave about 1/16" gap and pour the heat to it. I tend to be a little heavy anyway. When I TIG weld 18 Ga. sheet metal you can almost see the stacked nickels on the back side! LOL

 

[Zandoz]

I'm hoping to use 4"x2"x.125" tube for the frame, so there would not be a whole lot of material to work with.

 

[fluidfloyd]

Would doing fishplates on the outsides of the miter welds be an alternative to the inside splice plates?

Bill...I do fish plate butted weld joints like you are describing. I prefer doing it on the outside so I can put the butt weld joints in shear instead of tension. Putting them inside make you have to use rosette or plug welds or cut slots and run long beads. Being on the outside you have much better control of what you want that fish plate to do. Hope this tells you what you want to know. Take care.

George

 

[old round fart]

IMHO 2x4 tube is gross overkill. I have used 1 1/2x3x 120 for years. On longer cars and big blocks I may go to 3/16 wall.

 

[Zandoz]

Bill...I do fish plate butted weld joints like you are describing. I prefer doing it on the outside so I can put the butt weld joints in shear instead of tension. Putting them inside make you have to use rosette or plug welds or cut slots and run long beads. Being on the outside you have much better control of what you want that fish plate to do. Hope this tells you what you want to know. Take care.

George

That tellls me what I need. Thanks!

 

[Zandoz]

IMHO 2x4 tube is gross overkill. I have used 1 1/2x3x 120 for years. On longer cars and big blocks I may go to 3/16 wall.

There are a couple reasons for going with the 4x2x.125 tube. The first being that I need to run a 3" ID tube through the main rails, to get the R&P tie rod ends and bellows through. Another reason is that I want adjustable rear lower control arm brackets...the off-the-shelf brackets I have for accomplishing that in a decent looking manner are designed to fit over a 4" high frame rail.