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wythac Samba Member
Joined: August 02, 2004 Posts: 2791
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Posted: Thu Jan 29, 2009 9:07 am Post subject: Strongest way to attach flat tab to tube end |
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I"m going to tie a tubular rear sub frame into my shock tower. I am thinking that I will cut two open ended slots (across from one another) into the end of the tube (.120 wall DOM) about 1" to 1.5" back from the tube end. I'll then fab and insert an arrowhead shaped flat steel piece with a hole in it's end for a shock bolt into those slots. With the end of the tube still open, I would have access to weld the tab to the tube on the inside and out. I'd then weld caps to the open tube on either side of the tab.
Any suggestions for a better way of doing this? I'm thinking it would be plenty strong, with the overlap of the tab and the tube creating increasing the area available to weld the pieces to each other, but there might be a better mousetrap out there. Let me know what you folks think or have already done...I am always open to consider other ideas. |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20365 Location: Just a tiny bit west of Yosemite Valley
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Posted: Thu Jan 29, 2009 10:39 am Post subject: |
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Works for me....
Dale _________________ “Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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lostinbaja Samba Member
Joined: December 19, 2004 Posts: 4036 Location: Frankfort, Illinois
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joescoolcustoms Samba Member
Joined: August 08, 2006 Posts: 9054 Location: West By God Virginia
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Posted: Thu Jan 29, 2009 12:19 pm Post subject: |
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I think if you weld a plate into a tube, the weakest point will be the bolt hole in the plate.
If possible, I would make/use something like the tubing ends Lostinbaja shows. Something with a double shear. _________________ Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race
Everyone is gifted. Some just do not open the package.
Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone |
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wythac Samba Member
Joined: August 02, 2004 Posts: 2791
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Posted: Fri Jan 30, 2009 6:58 am Post subject: |
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Thanks for the suggestions. I was looking at it last night. The clearance between the tube running back from my mounting plate and the upper shock bolt won't allow enough space for a slot clevis. There is little more than 1.5" between the bottom of the sub frame tube and the top of the shock tower.
It looks like what I really should do is make to tab a little longer and fishmouth the top of the tab where it meets the tube and weld it directly to the tube. I can use half round short (1", like I said, not much room) sections of tube as gussets on either side of the tab, with a fishmouth on the tube side for added strength. This would give me four seams to weld the tab to the main sub frame tube.
I'll be looking for some of those slot clevises for a different application where I have some more room. I think you just gave me a great idea for a removable spare tire mount that is strong and doesn't use unsightly clamps or plates. I'm likely to re-engineer the attachment points for the engine cage with some of the slot clevises, especially where it attaches under the engine to the frame horns, where space is at a premium.
Thanks again for the suggestions. |
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xirxious Samba Member
Joined: November 12, 2007 Posts: 665 Location: Seattle
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Posted: Sun Feb 01, 2009 2:29 am Post subject: |
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Will it be pushing or pulling on the joint, or both? If its pulling, I'd make a U-shape clevis. You could also weld in a plug and drill a hole through. |
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wythac Samba Member
Joined: August 02, 2004 Posts: 2791
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Posted: Mon Feb 02, 2009 9:40 am Post subject: |
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I may still add some gussets to the shock tabs, but I am rethinking that for two reasons:
1.) I have the subframe tied into three other places on the shock tower.
2.) I think that adding a gusset to the tab will only concentrate any shear potential at the very end of the tab, where it is weakest.
I might double it up as a means of strengthening it, but not until later....I have a lot of other stuff to finish on this car if I am going to drive it this summer. |
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joescoolcustoms Samba Member
Joined: August 08, 2006 Posts: 9054 Location: West By God Virginia
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Posted: Mon Feb 02, 2009 9:14 pm Post subject: |
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Well I totally misunderstood what you were doing. Pictures speak a thousand words.
I like the sub frame. My opinion is that if you shear/break what you have fabbed up, you have more serious problems to contend with. I think with a hard enough rear end hit, it would possibly bend the top of the shock mount upward/forward before sacraficing the mount you have.
Nice job. _________________ Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race
Everyone is gifted. Some just do not open the package.
Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone |
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wythac Samba Member
Joined: August 02, 2004 Posts: 2791
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Posted: Mon Feb 02, 2009 10:30 pm Post subject: |
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Thanks. It was a long weekend. I still have a few more welds to complete, and a battery box to fab. My next challenge is to find a way to attach it to the rear hoop and suspend a rack inside the package tray from it while completely isolating it from the FG body. I have some remanufacturing of the existing engine cage to do as well, but that is less integral to the build and so it can wait. |
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Glasser Samba Member
Joined: September 18, 2007 Posts: 1640 Location: Calgary Alberta Canada
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wythac Samba Member
Joined: August 02, 2004 Posts: 2791
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Posted: Tue Feb 03, 2009 11:51 am Post subject: |
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Yes, I have a kafer bar assembly that is not pictured. It attaches on the inside of the shock tower, a separate assembly but strengthened by the addition of this piece. Look forward to seeing your pics..no such thing as too many ideas to consider. |
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Glasser Samba Member
Joined: September 18, 2007 Posts: 1640 Location: Calgary Alberta Canada
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