where to buy??? dump parts

The catalog I just received from Northern Tool and Equipment Co. lists just such a thing in it... it's on page 66, which would probably help if you were to order a catalog from northerntool.com (which is free). There's a few different kinds, ranging from generic flatbed kits up to ones for specific models of Ford, Chevy, and Dodge trucks. Prices range from around $870 up as high as $1550 depending upon what type you pick. Maybe something like that would work?

good one. I knew I've seen that stuff somewhere:

Thanks for the link. That is a kit. I am hoping to find just the scissor lift or the scissor lift and ram. If all else fells I guess I will be calling Northern Tool. Thanks again!
J> I am making a dump bed for my trailer. I am looking to buy a scissor

Jonathan,
I looked for plans myself and never found any. One suggestion would be to go to a local trailer dealer and explain what you're doing and if they have any humanitarian instincts at all they should let you measure the scissors mechanism on a trailer.
I recently bought a junked pickup dump insert ("Ace Dumpet", evidently belly-up as I can't find a reference to them on the web) with a scissors mechanism. However, a previous owner has evidently modified it so that a non-standard cylinder would fit. I haven't got it working yet and I hesitate to pass on dimensions that may not be the best configuration.
Another problem I've run into with mine is finding a cylinder with a small enough retracted length to fit, and yet still have a long enough stroke to raise the bed far enough.
I also spent about an hour doing google searches for "dump trailers" and downloaded and saved numerous pictures of scissors mechanisms. That might be a useful exercise and there seems to be a fairly wide variation in the way they're made.
Good luck!

Jonathan,
If all else fails, with all the photos available on the web, it seems like it would be a fairly easy task(famous last words) to build a full size working prototype scissors mechanism from scrap wood or even corrugated cardboard. You could use dowels for the pins.
From what I've seen from looking at mine the things to watch for are that the cylinder and rod have clearance from the mechanism at full lift and all intermediate positions, and of course that there is enough leverage available to lift the dump bed at full capacity.
Once you get it figured out, then you can transfer the dimensions to steel and cut and weld away. 's catalog has probably half a dozen 12V hydraulic power packs. I think that has the best source of good quality hydraulic cylinders. It seems that single acting cylinders are scarce, and you can use a double acting cylinder as a single acting one by putting a breather valve on the unused side of the cylinder.
I paid about $30 for a set of dump trailer plans, but the hydraulic system just used a straight ram, no scissors.
Bob