Heymow - Lawnmower Racing Forum

Mower Building / Setup Help => Chassis => Topic started by: snydas1987 on January 28, 2015, 07:25:21 pm

Title: 1 off Chassis building jig ideas???
Post by: snydas1987 on January 28, 2015, 07:25:21 pm
Hey guys,
Im almost ready to start building my chassis for my new racing mower project, been collecting all my goodies needed for the project and im now redy to get the welder out.
Im wanting an alternative to using a solid steel welding table that i could just tac the rails in place onto to make sure the frame would stay square and level as a weld it all together.?. I know this is the best and most preffered way but im only building one chassis and dont have that table setup which would also be a big outlay if i was to make a table.
So i was thinking about getting a 19mm sheet of ply wood and doubleing the thickness buy fixing 2 sheets 1 on top of the other which i believe would be solid enough to hold the frame rails to with a setup of G-clamps and be able to keep them all level and square while i weld it all together.
So what do you think of my plan?, will it work good enough or is it a failed idea?
Can you give me any ideas or methods you have used yourself, or that you think/know would be a better way to go about this step in building my chassis?
Or maybe you have a way of bettering my idea of using plywood n solid clamps? If so id love to here your changes and ways of doing this?
Thanks heaps guys and i will appreciate anything you can help me with on this topic??
Cheers Snyds
Title: Re: 1 off Chassis building jig ideas???
Post by: docbro on January 28, 2015, 10:01:41 pm
The problem I see with your idea, is that here in the states, any thickness of plywood will have some crown or be warped as it is taken off the stack.   It is only flattened when nailed or screwed to a frame that is straight and strong enough to hold it.  Another issue would be from the heat transfer during welding which could ignite the plywood.  Do you have a concrete floor level enough to lay it on?  Maybe a thinner piece of sheet metal on the floor to tack the frame to?  This would be a lot of stooping and working from your knees, but less cost possibly.
Title: Re: 1 off Chassis building jig ideas???
Post by: chavez on January 29, 2015, 12:17:22 am
I'm not sure the cost of steel down under, but if you are planning any fab work, a flat, square steel bench is worth it's weight in, well, it's worth a lot more than what it's made of. Otherwise, good ol flat concrete is your next best bet. Just watch out for too much concentrated heat on concrete, it'll pop like a fire cracker, sending pieces flying in your face.  Just ask anyone in a welding shop.
Title: Re: 1 off Chassis building jig ideas???
Post by: Huffy044 on January 29, 2015, 11:18:44 am
As much as we would like to do things differently, sometimes it just ain't going to work. My welding plate is 1" thick and 5 X 14', it has paid for it's self many times over the last 30 years. Make the investment. Besides, wood catches on fire LOL!
Title: Re: 1 off Chassis building jig ideas???
Post by: snydas1987 on January 29, 2015, 05:14:36 pm
Docbro- i was planning on making a frame of sorts to fix it to to stop that bending but with a 19mm sheet i didnt think it would do that to much.
I have a fairly level surface in my shed but i wanted a way to be able to clamp it in place so my welds wont be able to pull it out of shape, cause as you know as welds cool they can tend to move your structure, hence why the big sheet of steel works good cause you can tac each piece of the frame down before you join them together.
on the idea of using a thinner sheet of metal? wouldnt it just pull out of shape anyway as it wont have enough stiffness unless you get to 3/4" or 1"? thats why i thought going like 38mm of ply fixed together would hold shape better and yes i know wood burns but i just felt i could get a truer frame that way.
What price do you think a sheet of1" or even 1/2" steel would be?
thanks guys
i found so prices and im looking at only like double what it would cost for the ply wood idea so i think i should jus go it cause like you said even if i only build 1 mower frame il use it for many other little projects so thanks guys for pushing me that way.
At least i know im gonna have a straight n true chassis when im done.
So what thickness plate do you think i can get away with 1/2" or ???
Title: Re: 1 off Chassis building jig ideas???
Post by: Haganracer88 on February 04, 2015, 08:47:46 pm
The plywood will work just take a price of sheet metal and screw it to the top of the wood and then u won't have to worrie about fire and u can take a 2x4 and run it up the middle for an extra brace and that should work
Title: Re: 1 off Chassis building jig ideas???
Post by: chavez on February 04, 2015, 10:23:13 pm
Personally, I'd not go less than half inch. If you ever get to hammering on something, you'll like the thicker top. Then at that point you have something strong enough to bolt a vise to, or other things.
Title: Re: 1 off Chassis building jig ideas???
Post by: snydas1987 on February 05, 2015, 07:34:53 pm
yeah cool guys, thanks for all your input as this is where iv been stuck for awhile as i want a perfect chassis once done.
cheers