Projects 1928 Chevy frame build

[valkokir]

Over the last couple of weeks I have been starting on the build for the new frame for my car. If you are not familiar with early Chevys the bodies were a wood substruture with sheetmetal nailed to it. The suspension was parallel (sort of( leafs front and rear. The frame rails are angled front to back with the leafs inline with the rails. he original frame was in very bad condition because of how the car was stored and seems considerably worse anywhere that wood was in direct contact with the metal.

I managed to save only the front 36" or so which was protected by oil spray from the engine and also did not have wood in contact with it. The frame is 12' total.

I wanted to keep the original frame profile to look as original as possible. It has a cool lip on the bottom leg of the channel.

I had 7ga sheet steel (same as original) bent to match the profile and mated it up with the front frame horns I saved with fishplates for strength.

I had these parts sandblasted while I was working on the next pieces...

Since I have to rebuild the whole frame I wanted to incorporate a 4" drop to the rear. This will match the 4" I will gain by placing the front axle over the springs instead of under. I drew up the existing frame in solidworks and moved the spring mounts straight up 4". This put the front mount for the rear spring right in the frame rail. The car will be a highboy style so a simple Z'ed frame would show underneath. This is the concept I came up with. I wanted to step box the frame and add an X-member.

you can click on the picture and download view a 3D model by downloading eDrawings viewer.
I tried to carry the detail of the existing forging for the rear mount of the front spring into my spring pocket. I like how it looks and it gives me full spring travel.

To build the rear frame section I had the pieces laser cut from 7ga steel from my drawing.(I've already welded on the nuts for the bumper mounts)

I started by building up the spring pockets after machining the outer plates to match my drawings.

We machined the rear spring mounts from solid bar stock. The original forgings were worn out.

Here's a mockup with the main leaf



I started tacking the top channel leg on the profile shape with the intention of heating and bending the strap to match the profile.)

I didn't like how distorted the part was and how slow and inaccurate the process was. I cut off the strapping beyond where I had already welded and bent it to shape with small bends every 1" this was much faster and better looking. the small bends gave it a slightly faceted curve but subtle enough to blend out later. Made the fixture out of some 1/2" Aluminum tool plate. Plenty of clamps to keep everything from warping.

A little bit of fine tuning required to get the boxing plate to set in.

Here's the other half, shown flipped over and clamped up and ready to finish weld and fit the spring pocket.

A few pictures of the rail with the fillet ground and filled as necessary.

This will be joined to the straight channel at a later date. I'll then build a frame jig to suit for welding in the crossmembers.
Thanks for looking. And thank you for all the excellent posts in the past that have given me some great ideas.

Kirk

[youngster]

Very impressive! Nice work!

Ron

[Mat Thrasher]

Very nice, good to see early GM's being built.
Mat

[Twisted Minis]

Wow, very nice work.

[Speedsterinc]

Too Bad your not closer I am getting ready to part out a 28 Chevy cabriolet with an excellent chassis.

[ohiotj]

Nice to see someone else with a 28 Chevy. I''m pulling the body off the frame tomorrow. I think my frame can be saved, here's hoping.

Just curious, how are you planning on handling steering when you relocate the axle? I noticed on mine the tie rod would possibly have interference issues with the spring, and axle might be prone to bottoming into the frame.

[JRODHOTROD]

It looks like you have a smart approach to the frame rebuild. I look forward to seeing what you do with the rest of the car. Do you have any SLDRW or PDF's of the frame I'd love to add them to my collection.
-J-

[valkokir]

Thanks for all the kind words, I'm excited about the progress so far and can't wait to do more.

Originally Posted by ohiotj

Just curious, how are you planning on handling steering when you relocate the axle? I noticed on mine the tie rod would possibly have interference issues with the spring, and axle might be prone to bottoming into the frame.

Good question, I'm going to leave the steering completely stock to start with. I also see some issues with the tie rod on the spring but it's only at full lock turns, the tie rod will also hit the original front crossmember when the suspension bottoms out. I may trim or notch out the pan (it's in the indent in front of the original front motor mount), to be determined. The axle will definitely bottom out on the frame at some point but will miss anything critical including the grill shell. The obvious solution to this is bump stops. Obviously this is going to limit the suspension travel though, it's looking like I'll have around 3" of travel with the original axle. Look for pics of Kerry's (UserID KERRY) Chevy and his axle flip, probably one of the best applications of the original axle I have seen. I've got a whole bunch of threads on this bookmarked. There's still some uncertainty in the areas you mentioned. It won't break my heart to have to switch over to cross steer or lose the original steering column/gear somewhere down the road if need be but If what I'm seeing so far is correct, there aren't any problems that will prevent me from getting safely on the road.

Originally Posted by JRODHOTROD

It looks like you have a smart approach to the frame rebuild. I look forward to seeing what you do with the rest of the car. Do you have any SLDRW or PDF's of the frame I'd love to add them to my collection.
-J-

Best I can offer at this point is the eprt already in the thread, I don't have any formal 2D drawings of the frame except of the pieces I sent to the laser. At some point I'll get around to this but they really aren't necessary since nothing is being sent out to be built.

[29bowtie]

Very interesting, and well thought out. They are a very good frame to build from. this is my 29 which is the same fame as a 28.

[ohiotj]

Thanks for the info - your front springs must bein better shape than mine. If I swapped the axle right now, I'd probably have about 1" of front suspension movement. I'm snagging my father-in-law's used 1930 springs (he replaced his with 1930 Chevy truck springs), in the hope that'll give me a bit more lift before I move the axle.

I've looked at some of KERRY's replies, and am hunting for the original build thread as we speak. Looks like I'll be doing some grinding on the axle.

[valkokir]

No problem. Actually I think my springs are pretty well shot, more than likely I'll at least be getting some new main leafs but I'm not even going to think about that until I see how it sits once together. I'm confident on their dimensions and location since they're staying stock but I don't want to speculate on spring rate and arch until I get the car together.

Originally Posted by ohiotj

Thanks for the info - your front springs must bein better shape than mine. If I swapped the axle right now, I'd probably have about 1" of front suspension movement. I'm snagging my father-in-law's used 1930 springs (he replaced his with 1930 Chevy truck springs), in the hope that'll give me a bit more lift before I move the axle.

I've looked at some of KERRY's replies, and am hunting for the original build thread as we speak. Looks like I'll be doing some grinding on the axle.

[captainjunk#2]

some nice fabrication work there

[valkokir]

Long delay between posts but back at it again with some more progress:
I was a little negligent on the picture taking when joining the previous work shown above together into a complete frame rail but you get the idea.
Started by tacking rear frame sections to channel, note that it is “keyed” in to carry the bottom lip detail right up to the spring pocket.

Fishplate inside frame to strengthen joint

Front and rear sections fully welded and ground, bottom lip detail will be blended into spring pocket at some point, just need to decide how I want it to look

Bolted the front and read crossmembers in for mock-up (will be welded in)

Original rear crossmember fitment to new rear frame sections

Original Front crossmember bolted in place

Starting to fit the boxing plates, step-boxed with a .27" step from plate to leg of "C". Most of the plates aren't sitting in all the way right now because they are hitting the bolt heads.

More boxing plate fitment, the wood block sets the plate in the proper depth, really unnecessary and not strong enough to use to weld but seemed like a good idea at the time. There are also wood blocks between the "C" and boxing plate for mockup.

boxing in around the steering mount (original forging) The stop/start of the boxing plate here is in a very obvious place in the open engine bay. Dad's good idea here on the 45degree bevel.

Just another detail shot.

I'll still need to fit the plates for the front frame horns (remember, it's a Chevy so those are structural also) Weld nuts added for front bumpers (probably won't run a bumper though)
Some of the extra holes need to be filled in the front section still.
Some holes and weld nuts will be added for the body mounts.
The next big step will be to build the frame fixture. The large rectangular tubing will be the base of the fixture, leveled and bolted to the table top.

Thanks again for looking

Kirk

[valkokir]

ttt for the morning crew

[ss34coupe]

fantastic work! keep the pics coming.

[kustombuilder]

real nice work!

[valkokir]

More build updates: As usual click on the images for a larger version

December 20, 2008 - Jan 4, 2009

Fixture Construction: Frame is leveled and straightened to hold critical points square

Frame was then disassembled again. Stand-off tabs added for step-boxing. Inside rails primed with U-POL for rust-resistance

Added some details back in that were lost with the new rear section

Added rivets back in (silver brazed or welded from back side where accessible)

The piece of square steel tubing near the front sits behind the motor mount bracket for strength. More detail of stand-off tabs.

Boxing plates to be prepped with U-POL

Frame fitted back together shimmed and leveled. Crossmembers welded to frame rails and boxing plates tacked in and marked for stitch welding

Starting to weld boxing plates in.


Clamping and tacking the center crossmember. I designed the crossmember then had it laser cut & folded

Trans crossmember shown here is bolt in. Also Laser cut and folded

This piece was an original crossmember that served as the mount for the emergency brake hardware

The original crossmember before modification is sitting on the table in this picture

It was pie-cut and fit in place. It will serve as the e-brake swingarm mount again.

[valkokir]

Engine set in place and leveled left to right and angled back a bit.

Brackets are squared up on the Bridgeport and bolted to the engine mounts with a temporary aluminum spacer. A gusset plate fills the gap.

engine dressed out a bit to see how it all looks and fits


top plate for center crossmember is hand cut and bent

Engine pulled back out to finish welding the crossmember


Finished, aside from some finishing touches and paint.

[skottyknukkles]

very nice!

[Ghost28]

A little break an back at it. Man you do some nice work. If your frame looks this good I can't wait to see the rest of the car. You make us chevy guys proud. Keep it going and more pics as you go. Thanks ...ghost