Project Hellraiser 3

Page 3

   
 
 

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With the lower part of the chassis done it is on to stage 2 of the plans which gets into the middle of the chassis.

First up were the 4 uprights at the corners of the passenger compartment.  These were straightforward cut and notch.  The front two uprights sit on the nerf radius so you may want to turn the notch 10 degrees on one end.

To locate the uprights I measured off the required distance from the front tube and then tack welded a piece of 1.25 square steel tubing to the chassis to serve as a locator.  Make sure both sides measure the same which ensures the locator is square in relation to the front of the chassis. One trick I learned after I did this was to clamp a piece of u-channel onto tubes to make a straight reference edge. Measuring based on the center or edges of tubes leads to errors.

Next I measured and marked the location for the rear uprights using the flat face of the locator bar as the start point.

I tack welded the front upright in after making sure it was vertical in both directions using a level.  This is where the tube clamps I picked up from Van Sant come in real handy.

Next up is the front shock hoops.  These need to go from the front upright and tie into the front bumper tube on the chassis.  Here is where I deviated from the plans a bit.  First I added a few inches to the initial cut length since this was going to be a tricky fit. I also only cut one tube in case I messed up.  Also, I 'd advise you to keep notes of what you do, it'll help for the second tube for the other side.  In this case I wrote down the new cut length and the initial bend which I purposefully came up short.

Next I notched the upright end of the tube (writing down the notch angle) and fitted the tube in place (picture on left).   I could see I needed another 10 degrees of bend to get the tube to line up with the front bumper tube.  I crept up on the bend by bending, then checking, etc.  Once it was close I cut the un-notched end in the chop saw to the angle required to let tube the sit on top of the front bumper leaving about .25" extra.  Now I set fit up the shock hoop and marked with a sharpie where I need to grind it to allow it to set down on the bumper tube.  It doesn't take much grinding to get it sitting nicely on the tube (picture on right).

   A quick check shows this piece will work on the other side with the same angle and length (but different notching) so it is ok to cut the passenger side shock hoop and follow the directions I wrote down to get it nearly identical to the drivers side. Once both shock hoops are done I just have to get them setting at the same angle.  To accomplish this I took a sheet of steel and held it against the upper part of the hoop.  I then stuck the angle finder on the steel and dialed in the desired angle.  Repeat for the other side.

Here is the really nice thing about my little chassis jig, at the end of the day I can roll the chassis out of the way, clean the garage, then park the chassis in the corner.  This is so much nicer than having it stuck in one place on jack stands. What is shown above is roughly 4 hours of work and I am about halfway done with stage 2.

I picked up where I left off on stage 2 and started in on the tubing that would form the perimeter of the buggy at the beltline.  I did these in 4 pieces - you could technically do this in two pieces but if you messed up on the multi-plane bend you end up wasting a whole stick of tubing. I chose to go the safer route which requires sleeving some tubing but it allows you to simplify the bends and make adjusting the angles easier.

I started with the rear pieces which basically make a large "U" shaped piece of tubing that ends about 10 inches from the front "A" pillar.  To keep the tubes lined up with the "A" pillar I temporarily sleeved a straight piece of tubing to the rear tubing.

I made another sleeve where the two rear pieces of tubing meet in the rear.  For now I just drilled and plug welded one side, when I am ready to final weld I will add plug welds to the passenger side.

Once the rear pieces were done I could make the final two pieces that tie the rear tubing into the front hoops.  This is where it can be tough to get both sides to line up perfectly, I ended up partially notching the tubing with a hole saw, then crept up on the final cut with the grinder.  I did have to cut the tack welds on the front hoops to get the short piece of tube over the sleeve and into position.

A quick comparison with my 3 seater shows this chassis is pretty much the same length nose to tail. The engine bay in this chassis is also a touch bigger than on my 4 seater, I did this to allow a bit more room for component mounting.

Today's bit of work took about 6 hours, most of it involved measuring and notching to get everything symmetrical.

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