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Warp prevention...



wellis77
10-19-2010, 09:02 AM
I'm going to be building a chassis/frame table for myself in a couple months and have recently been thinking about the best way I can weld this together to avoid warping. I've read multiple threads on different and heard about bolting top rails to the frame of the table to avoid warping but I'm having a hard time picturing what that looks like.

Outside of that, what are some ways I can avoid warping, as much as possible. Until last week, I figured I would stitch weld 1 - 1 1/2 inches per leg, then about an inch on each side of the 2 x 2 cross braces. From other threads I've read that seems to be a pretty common way of welding a table together, aside from bolting on a top rail but I haven't seen a pic to know what that looks like. Earlier this week I found some "welder angle clamps" and it got me wondering if this might be a better option. At $40-$50 a piece plus shipping, they aren't cheap but it may be worth it in order to be certain everything is square and true. Any thoughts on these clamps and if they would be worth the investment or other ideas on what I can do? I can probably use them also for squaring the rails on my frame too, and who knows, I may be able to find other uses as well.
http://cgi.ebay.com/4-Industrial-Wel...#ht_2871wt_907
http://i876.photobucket.com/albums/ab324/wellis77/weldingclampvise-3.jpg

Below is an image of my design so far. I'm planning a 15' table with the side rails out of 3x3x1/8 box tube, cross braces and angled leg braces out of 2x2x1/8, legs are 2x3x1/8. I'll be building adjusters into each leg in order to level it out.
http://i876.photobucket.com/albums/ab324/wellis77/chassistable.jpg

If you're not familiar with a table like this, I'll be mocking my car one it, using a jig to establish my suspension pick-up points and building the chassis on this as well. My main concern is warping of the table as I weld it together but if you have other ideas of what I can do for this I'm open to hearing anything. Thanks everybody, good to see you all again.

Hopefully this all makes sense too. I've adapted it from multiple car forums...

SICFabrications
10-19-2010, 11:38 AM
i NEVER weld the table top to the table frame.... when you weld it, it WILL warp and bow... trick is, you gotta use a steel top thick enough to not move around.... you also gotta use frame parts heavy enough to..... not move around....

wellis77
10-19-2010, 12:44 PM
I'm not using a top. It's going to be open so I can work and weld from underneath and inside too. Any thoughts on how I can put this together to minimize or eliminate possibility of warping altogether? I hate to have to bolt the entire thing together but that may be the best situation. Any thoughts on whether or not the clamps I listed would be a benefit?

SICFabrications
10-19-2010, 01:04 PM
i'll get back to ya on this later tonight..... i dont have any clamps in my inventory that even remotely resemble those clamps.... other peeps use em, i dont.... if you lightly tack corners, inside then out and constantly check for square plumb, flush, and level as you are tacking it together, then you should outta be fine.... after its tacked, then weld a joint on 3 sides, then jump to another part of the table... keep moving around and making square adjustments as necessary

tomsign
10-20-2010, 04:47 AM
well put Stan

ISKI
11-08-2010, 11:09 AM
I used two 6 inch I-Beams for the table, and then I use 2x3x0.128 rectangular tubes to slide up and down where I wanted to set a datum. I bolted two 6 inch I-beam rungs in the middle to hold it together and added wheels so I could slide it around. I used a water level from home depot to get the four corners set. I was worried that it would warp when I welded it, and decided that the best option was to use screw adjusters out of inch bar from home depot to set the level. After this I wanted to put turn-buckles from the jig to the concrete to keep it from twisting or lifting. I also set the suspension mounts using the jig/ chassis holder vs. the frame rails so that the holes are exactly where I want them in relation to each other. The I-beams alone did the job for my 4 inch 1020 DOM tubes. If I ever use it again, I’ll turn buckle it to the concrete floor for a perfectly solid datum. I like the I-beams since I can unbolt this thing and store it in almost no space at all.

I have a picture of some of it in my gallery

KHK
11-08-2010, 12:41 PM
From my experience, which is limited, I have found that if you get things to hot it will warp. I would recommend that you spot weld it together, check for square and adjust as needed. Do the final welding by moving around to keep any area from getting to hot. You do not really care if the legs are square and plum only the main tubular top of the table. Bolting the assembly to the floor before final welding should help to keep the top true.

tigqk
11-17-2010, 02:13 AM
Got a chipping hammer?

wellis77
11-17-2010, 06:20 AM
Got a chipping hammer?

yup, sure do

UnfinishedProjects
12-06-2010, 10:10 AM
Wellis77,

Like every mentioned, I always have luck tacking and stitch welding but moving around on the project. Just don't spend to much time in one area and you will be ok.

By the way, how do you determine the width for your table? Tire-to-tire distance? I would love to build a similar table but I want to make sure I can build multiple cars on it no matter their width or length.

wellis77
12-08-2010, 12:53 AM
UFP, I was originally going with a width that would allow me to set the tires on the rails but recently talked to a guy that works in a shop in Ontario. He showed me some pics of the tables in their shop and was saying max width should be 3 feet.I was a little floored by that but he was saying it works out perfect because you run cross members to your suspension jigs if you are using those, cross members to attach the body, but more importantly, it allows you to work on the car/chassis without having to reach over the perimter rails. You can literally get into the wheel well if you need to. His recommendation is also NO top to the table so you can get into the car or under it easily.

Check out some of the pics on this page, '80 Camaro - Lowdown Hot Rods (http://lowdownhotrods.smugmug.com/What-weve-done/Current-Projects/80-Camaro/12157989_TrSYL#1001972675_Y9GdE). So I've redesigned my table similar to what they use in this shop. I'll still be using a total of 6 legs for my table, though he was saying deflection of the table with 4 legs in the corners and 64 Impala on top was 2mm in the center of the rail.

May different opinions on how to do this well and the design I like the most is what I described above. Check out this thread if you want more reading material, chassis jig design (http://www.pro-touring.com/showthread.php?38625-chassis-jig-design). I'll get some pics up next week when I get back to the States and get mine built.

Will

UnfinishedProjects
12-08-2010, 01:25 AM
Thanks for the advice. I have seen so many styles of tables, I'm sure they all have their ups and downs, but the open top table seems good to go. Especially for getting into hard to reach places and saving some money (less steel = lower price tag) on the table as well.

What about your wheels/tires, won't they just hang off the car since they are unsupported? Do you just have to use some type of support or stand to jack up and keep the tire bottom of the tire even with the top of your table?

wellis77
12-08-2010, 05:25 AM
I agree with you on all counts, especially cost. I'm building mine from 3x3 box tube and looking to save a few pennies when I can.

For my wheels and tires I'm going to do almost exactly what you describe, but using outriggers level with the top of the table. This will only be temporary because designed and had some fixtures cut to hold my suspension jig at ride height. Here is a pic of what I put together. This combined with my suspension jig will set my pick-ups and I'll be good to go, building the frame around the pick-ups.

1659

UnfinishedProjects
12-08-2010, 05:40 AM
Ok, sounds like it will work. I read through the thread on Pro-touring.com and found some good info. Your car is going to be bad a$$. I added a comment about building for a chassis that will "lay frame" when the air suspension will be lowered. Let me know what you think and if you would build the chassis at ride height or at slammed height.

wellis77
12-08-2010, 07:18 AM
I saw your post over there and did comment. I'm doing pretty much what you described. I'm using Viper suspension plus Ride-Tech shockwaves for my build, though I won't be laying frame-just setting down on the bump stops, and need to narrow the track. In doing so I need to figure out how much I need to tuck the front tires to account for 2.1" of compression at full lock. To do that, I'm going to use a 2x4 tube outrigger to hold the wheels/tires in place, plus a 1/8" shim to account for the .1", than work the wheel/tires back and forth lock to lock and adjust the track until I have probably 1/2" to 3/4" fender clearance. Then I'll set my suspension jig where the tires lay and start building my chassis around the jig.

I imagine you can do the same thing at your 4" ride height then to account for laying your frame, just use 2 2x4 tubes. Seems like a solid plan to me. I'm looking forward to seeing your build. What are you doing for suspension?

UnfinishedProjects
12-08-2010, 07:37 AM
As it the trucks sits now, it has air bags front and back and lays frame and rocker. My dad and I back-halfed from the cab back with 2 x 4 x.120 box tubing back in 2001. The 10-bolt rear end uses a triangulated four link.When I finally get a long enough set of orders and can buy a house, I'm going trailer that thing from my dad's to where ever I am and start fresh. I think I will use the stock frame and back-half as a template, build a full chassis then sell the frame off. I would like to do IRS, that's why I was asking about your set up. Maybe go with some shockwaves as well. The front suspension is simple but will work, drop spindle, modified lower control arm and air bag.

wellis77
12-08-2010, 07:47 AM
Sounds like a cool project. If you are going to full frame it anyway, I don't see any reason not to go IRS. If I were doing a truck, I would even look for a C6 transaxle. Ironworks has built a truck with C6 front and rear (I'm pretty sure) and it's freaking amazing!

UnfinishedProjects
12-08-2010, 07:56 AM
Yup, that is really what I want to do. You can get a C5 rolling chassis kinda cheap on ebay or even a worn out or salvaged one cheap as well. Yeah, that truck is nothing short of amazing. I really like the rear set-up how the shockwaves are tucked in tight to the center of the frame and use links to push up and down on the control arms. Not to mention using that transaxle puts some more weight in the back of the truck.

ISKI
12-12-2010, 08:41 AM
Will, when you move the wheels in, remember to check the bump steer, contact patch, and roll center with math / 3D models, or with a simple string computer. I figure you already know about all of this, but some don't and end up with squirrelly suspension.

Iski

wellis77
12-12-2010, 11:20 PM
Iski, I'll be checking all that using Suspension Analyzer. Although, none of that should change since I'm using factory Viper pick-ups. the only thing that could be different is bump since I'll be having a custom length steering rack built by Woodward Steering. Even then, there tech pages give some good information on determing where the pivots of the steering rack should be. Still, that is the one thing I need to be real mindful of front and rear, since I can't use the factory stuff because of the narrowed track. Thanks for the reminder though.

I'll be getting some pics put up by the end of this week. Only three more days before I'm FINALLY able to get work putting this table together and playing with my new 50D and Mig 205...

ISKI
12-13-2010, 12:14 PM
Suspension Analyzer or equivalent is the ticket. I wish I had purchased a program as it would saved me a lot of time.

wellis77
12-13-2010, 01:36 PM
I'm definitely not purchasing it, I'm using the free trial download. I think it's only good for two days so I need to have my junk together before I go to town on my junk.

ISKI
12-13-2010, 02:45 PM
Setup a second machine, have a freind download it again, and when you boot up each day, reset the calendar before you run the application;) Maybe you could set the machine to 1901. Good luck with the design.

wellis77
12-14-2010, 12:40 AM
Does that work? Huh.

tigqk
12-15-2010, 01:55 AM
Getting back to your chipping hammer, if you smack the welds wile hot it releives the tension on the weld, does nothing for the appearance though,it is more prevalent and obvious when you are welding sheetmetal - hammer forging, weld an inch, on dolly the weld, the weld disappears and removes stresses, do it again until finished - how I was taught anyhow.
As for releiving your stress on the table, plan your spotwelds and if you can place three in one side try to put three on the other side of things, and pay attention to technique, bevel where you need to to keep yourself from overwelding and do it quickly to keep the heat down.

mdkrusemark
01-09-2011, 11:59 PM
If you havent built the chassis table yet I would seriously look around for a used frame straightening jig from an autobody shop. They are old technology now but are made of I-beams with large casters and machined top surface on the I-beams. They are around 3 ft wide. If you find the right one they even come with pinchweld clamps distance measures, etc. The shop I worked at had one. They go for scrap metal price.

wellis77
01-10-2011, 03:55 AM
Already built, done and done! I looked for some old frame tables but had no luck. I haven't had a chance to put any pics of my work up here yet but I'll do that shortly.