1934 Pontiac Convertible Coupe

[Ed Davidson]

Started a job restoring the wood on a 1934 Pontiac Convertible Coupe, it's been very tough to research.  The car has been redone over the years and not much makes sense when I try to fit it together.  Simple question: How thick were the sills on the original car??  The ones I have to work with are made of two layers of 3/4" boards laminated together, but I suspect they were 1 3/4" on the original car.  I'd love to see an original or faithful restoration.  Any experts out there?  email edswoods@comcast.net.  The owner of the car is getting impatient!

[padgett]

Might be better in general discussion.

[Bloo]

I don't have access to anything 1934. I might have some pieces of 1936 sill out in my shed, I'll have to look. Do you mean you think the whole sill was 1-3/4 thick or the boards? I seem to recall two equal thicknesses of board, maybe about 3/4" each. Sills were laminated, probably to control shape with temperature and humidity changes. The whole quartersawn-vs-flatsawn boards thing probably comes into play as well but I am not sure exactly how. Fisher boards for lamination in general do not seem to be any particular standard thickness, although they may have had to keep the thicknesses equal on a sill. White Ash was always the preferred wood for body building, although you can find almost anything in a Fisher body. I think I found some Beech in my doors, too rotten for positive ID but definitely not Ash. Fisher made so many bodies they may have had to make some compromises, though I suspect a sill would always be Ash.

 

Sorry I couldn't be more help. The most useful manual for a wooden Fisher body of any year is the 1926-1931 edition. It is posted here: http://chevy.oldcarmanualproject.com/fisher/2632fbsm/index.html

Sadly, I am pretty sure it is not going to answer the question you asked, but if you haven't seen it you may find it useful. There are some other years of Fisher manual on that site as well: http://chevy.oldcarmanualproject.com/ .

 

Welcome to the forum!

 

EDIT: Posting this in general, or better yet technical, would be a good idea. @chistech or @Cabnut might know something. Both of them have way more experience with Fisher wood than I do.

 

EDIT2: I just realized since it is an open car Fisher may not have built it. Do you know who did?

.

 

Edited December 26, 2020 by Bloo (see edit history)

[chistech]

Your main sills were most likely 1 1/2” thick. I make new sills out of solid 1 1/2” ash and rabbet or inlet any areas needed where some of the inletting, like the floor board area, was made by stepping back the edge of the top board on the original sills. I can’t tell by the pictures but between the two sides you probably have enough wood to duplicate what’s there. I found that these cars were intended to be mirror images side to side but wood pieces fitted by individuals on the assembly line often didn’t come out identical. I made mirror images on the restoration of my 32’ Olds convertible and found with little hand fitting, all the metal fit perfectly to the new  wood I made. My restoration thread is her on the ACCA and with it being a cabriolet and just two years older than your customers car, it should be fairly similar in construction. While the body should have a “Fisher” tag on it, as Bloo said, none of GMs early convertibles were made by fisher but were sub contracted out to another body builder that no one seems to know who that was as there are no records. The are also no records of open bodies being built in the Fisher records. I don’t know if this was still the case in 34’ but know it to be the case in 32’ and prior years.

[Ed Davidson]

Well then I'll go with the 1 1/2".  This Pontiac was a cheaper car than what I customarily work on, Dusenbergs and Packards and Lincolns, which have all had 1 3/4" sills.  The mounting on the chassis is not very stable, which is another problem.  The sill is bolted at the cowl and crosses the frame at an angle, ending up on a bracket only 2" extended from the frame, while the wood at that point is around 6" wide, so there's a lot of overhang.

[Ed Davidson]

I do have a Fisher Body service manual that came with the car, in it is a picture of the wood but it isn't a great deal of help.  I'll check out your thread, thanks.

[chistech]

1 hour ago, Ed Davidson said:

Well then I'll go with the 1 1/2".  This Pontiac was a cheaper car than what I customarily work on, Dusenbergs and Packards and Lincolns, which have all had 1 3/4" sills.  The mounting on the chassis is not very stable, which is another problem.  The sill is bolted at the cowl and crosses the frame at an angle, ending up on a bracket only 2" extended from the frame, while the wood at that point is around 6" wide, so there's a lot of overhang.

The majority of the average wood bodied cars from GM (chevy, pontiac, Olds, some Buick’s, )were that way. The front body bolts go through the wood at the cowl and through the frame. The sills then curve out and usually mount on angled steel mounts riveted to the frame. The rear body mount is usually a formed steel bracket that bolts both to the rear cross sill and the side kick up. The cowl bolt is considered #1 mount and the numbers progress up as they move rearward. I would assume you probably have 4-5 mounts on each side. The 2nd, 3rd, & 4th mounts are usually carriage bolts in large cup washers set into the wood sills with round inlets. The front and rear mounting bolts are standard hex head bolts. All hardware is normally 7/16” x 14 for the mounts. The lesser GM cars didn’t have the body mass of the larger cars hence the 1 1/2” thick sill vs. the 1 3/4”. Of course the door shimming process works off the position 2 & 3 mounts when the time comes. Sometime position 4 comes into play to open or close the gap at the B pillar. (Either the latch pillar on conventional doors or the hinge pillar on suicide doors) Seeing that your Fisher book shows the 34’ cabriolet tells me they brought the open car body production into the Fisher plant which had to have occurred after 1932’. 

[Ed Davidson]

Thanks for your reply.  Very helpful information.  I have several other car projects in here but am running out of excuses on this one!  Got to get it going.

[Ed Davidson]

Chistech, if you wouldn't mind answering another small point that I don't quite get, is the fact that the rear brackets for the sills are mounted about 3/8" lower that the top of the frame.  This was factory, because the vertical arm of the bracket is riveted in.  Tis means you have to add 3/8" to the regular shims, making the whole connection more precarious than it should be.  

[chistech]

If you look at my restoration thread in the forums here (32' Olds Deluxe Convertible Roadster) you will see 1/4" thick, 4" x 4" (approx) squares of ash brad nailed to each mounting area on the bottom of the sills at those areas you describe. There was then 1/4-3/8" canvas reinforced pads along with varied steel shims (1/16 up to 5/32") at each location to get the body and doors right. The cowl and rear mounts had no shims other than thin sheet rubber. So basically #2,3,4 would have the 1/4 ash squares nailed to the bottom of the sills, then the shims and thicker rubber.  With all these pieces to the mount, it allowed for mounting the body just a little lower yet to have some flex in the middle for adjustments. If the riveted chassis mounts were as high as the chassis, any shims or dampening rubber would lift the body even higher off the frame. This mounting also allowed for the cross sills, floor pans and tools trays to stay close to the chassis without contacting them. This whole rubber and shim system was very secure and not as precarious as you might think. Hope this helps.