chassis jig design

[Mathius]

Just a thought, could house type screw jacks be adapted for the adjustable legs? They are cheap,very simple and some have a rating of up 12000 lbs.

Art

Making a setup mobile is easy, there are tons of options. Braking is more important. You don't want that thing to start rolling when you have a 2000lb or more chassis attached to an already heavy steel jig, + the weight of the frame. I realize a chassis jig is for the frame, but at some point you will want to seat the body for test fitting.



Your screw type setup sounds ideal for a break. Screw the legs down to seat it in place. We have a setup on our 'lock' machines where you can actually push a foot pedal and it releases the brake. Maybe someone makes something like that on a castor?

Mathius

[MrQuick]

Making a setup mobile is easy, there are tons of options. Braking is more important. You don't want that thing to start rolling when you have a 2000lb or more chassis attached to an already heavy steel jig, + the weight of the frame. I realize a chassis jig is for the frame, but at some point you will want to seat the body for test fitting.

Your screw type setup sounds ideal for a break. Screw the legs down to seat it in place. We have a setup on our 'lock' machines where you can actually push a foot pedal and it releases the brake. Maybe someone makes something like that on a castor?

Mathius

Great point. I've used 1" acme thread screws but don't recommend to be longer than 3" for the very reason Mathius stated. The more legs the better.

As for castors I recommend them to be used temporarily for moving or positioning. IE: backing off the jack screws to lower on to the casters or a adjustable castor mounting arm. Very dangerous to keep it on them. Also may damage the wheel or bearings. Casters are available with braking levers.

Scotzilla, im in San Carlos. Just south of San francisco.

[wendell]

This thread got dumber by the minute for a while. Looks like JP got it back on track. For retactable casters check out my post and pic, 3/4 the way down in this thread:
https://www.pro-touring.com/forum/sh...=welding+table

While I built them so I could move the table, the same design can be used fo leveling pads (basically the opposite, static casters). I've since added a single large ball bearing between the top of the caster and the bottom of the bolt. Focussing the load on the very center of the bolt has made it VERY easy to screw down.
EDIT: To Mr. Quick's point about the strength of casters; the scafolding casters I used are huge and well with in their load range. They were probably expensive. The same can't be said for the casters I used for my TIG cart. I wanted to keep the cart low profile and was being cheap. The result after a year is four squar wheels ready to start puking bearings any minute now. Leason learned.

[lz07rp]

A friend of mine just built one out of H-beam. It's all bolted together much like the ones in the pics. If you go with the acme screws for the leg adjustment enco and msc sells different lengths and sizes for a decent price. Post some pics when you get it done.

[Mathius]

Great point. I've used 1" acme thread screws but don't recommend to be longer than 3" for the very reason Mathius stated. The more legs the better.

As for castors I recommend them to be used temporarily for moving or positioning. IE: backing off the jack screws to lower on to the casters or a adjustable castor mounting arm. Very dangerous to keep it on them. Also may damage the wheel or bearings. Casters are available with braking levers.

Scotzilla, im in San Carlos. Just south of San francisco.

That's how the castors on our lock machines work. You hit the pedal, castors come down, feet go up. Hit the pedal, feet come down, castors go up. These things are WAY too heavy for me to try and get under them and see what they look like, not to mention my shop foreman would be asking me wtf I was doing.

Mathius