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Repairing Top frame wood


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Looking at a 1929 four door sedan that has an issue with some wood framing needing replaced as well as the top.  All wood is in the roof section. One piece looks to be along the front / visor area and the other is one of the back corners.  Being the top would be coming off in the future fall for replacement just how big of a job is it replacing pieces?  I am not a novice or even handyman wood worker by any means but not a furniture maker either. Have most tooling of a cabinet shop as I do like to dabble in making things. Large band saw, table saw, pocket hole machine, router table, joiner, surface planner, etc.. I have good knowledge of joining lumber through mortising, etc.    So in the skinny, how did Franklin join their framing together? I am sure our glues and joinery has advanced today for sure.  When replacing framing like this just how much of the car needs disassembled? The rest of the lower side of the car seems fine with no sag in the frame. I would be the 4th owner of the car and the maintenance of the car with records since new is top notch. Just an older 1960's restoration that has some issues that need addressed but is a very mechanically sound car.  I am guess the top replacement is would the easier of the issues.?  Any input on that as well ?

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Franklin didn't join them, Walker did. :D

 

Walker Body Co. of  Amesbury Mass built the that body for Franklin. http://www.coachbuilt.com/bui/w/walker/walker.htm

 

They had their own style of wood layout and where/how joints are. Rather strong compared to some of the  competition.  They used casine glues and steel screws in the joints. Then steel plates over graphite asbestos "anti-squeak" paper screwed on at key areas.  Then it was painted black to help seal it.

 

You can do the same using slow-cure marine grade epoxy glue, or Weldwood or Elmer's Carpenter's glue, and wood screws. 

 

Don't butt-join the new wood to old. Instead use scarf joints which are stronger because the angled cuts (12-1 ratio) allows side grain to be glued to side grain. End grain to end grain joints are extremely weak and useless in auto body work. There are many ways to make scarf joint - most being "locked scarf" joints. Here's a simple one we used to scarf new planks, ribs, and spars  on wooden boats. http://www.craftsmanspace.com/knowledge/scarf-woodworking-joints.html

 

If you don't want to add complexity to a scarf joint by stepping it, to keep the joint from shifting and sliding during glue-up just tap a few small nails into one half of the joint and clip them off about an 1/8 inch sticking up. Then position the other half of the joint and drive them together. Lift off, spread your glue, and put the "pins" back into the holes made when you drove the joint together. The pins will keep the wedge shaped joint from sliding with clamp pressure.   Pix below are the body sills of a 31 Derham bodied Franklin that I scarfed new ends on all four corners, plus a new trunk deck.

 

For repairing small spots of rot that won't affect the frame strength, forget the off-the-shelf rot treatments. They can't soak in completely enough and the rot will continue to travel inside the wood, unless you can keep the moisture content of the wood down to that of a climate controlled museum - which you can't.  Dig all the rotted wood out and fill with a mix of epoxy and sawdust. Dam the mix in place with overlapping strips of masking tape as you fill the cavity from bottom to top. Sand to shape when mix has cured.

 

Paul

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Here's some other examples of repair joinery.

 

The first picture is a stepped scarf joint of the post at the rear edge of the passenger rear window of a 29 Franklin Victoria. Good for when you may not have enough length to get the ideal 12:1 joint ratio to gain maximum glue joint strength. The butted step is placed in the middle of the joint length where it will have the least effect on strength of the joint.

 

The second picture is the driver-side rear corner post of that same 29, with a scarf joint just below the belt line, and a new "foot" that fits into an open mortise of the rear cross sill. While the post foot is not a real scarf joint, it is taking advantage of the curvature of the bottom of the post to get a strong side-grain glue joint as the grain runs straight compared to the curve of the post.

 

Same for the bottom of the wheel arch in the background beyond the c-clamp.

 

Paul

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And here's some 29 new roof rails and front bow.

 

The rails are rather complex because they are made of several layers, with the corner joints overlapping the next piece rather than having the joints line up and cause a weak area. So you may be able to replace to an exiting piece, tie into the original joint, and not have to get fancy with as much mid-length joinery  when you get the top uncovered.

 

Walker liked to use nothing thicker than 2-1/8 white ash (10/4 dressed to 2-1/8).  So, by layering they could build up the thickness of the pieces and keep the joints from lining up. That makes some of wood replacement in the roof rails a bit easier.

 

You can see how the inside curve of the rear corners are routered to inset the steel reinforcing plates and anti-squeak paper to lay flush. Hopefully you won't have to get at areas like that, because you'll have to remove some of the interior.

 

And the last two pictures are the new rails and bows installed.

 

You can make anti-squeak the way Derham Body company did. Cut up cotton cloth and dip in melted candle wax. Hang to let the pieces cool and excess wax to drip off.  Cut to shape with plain scissors.

 

Paul

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Here's a picture of filling in rot in the rear of the driver side roof rail of another 29.

 

Note the angle of the scarf joint is not 12:1. It can be a shorter angle because it doesn't need max strength here. It's glued on top of the roof rail layer below it that forms the side window header.

 

Also note the gray areas  at the front of the new wood and inboard are a mix of epoxy glue and fine saw dust  formed into the last areas of rotted wood that was completely dug out back to good wood. This was not an area that needed strength, it just forms the curvature and attachment points for the top covering materials.  So rather than do more cutting/fitting work to make a larger wood filler to get 100% those areas filled with new wood, the mix was used and sanded to the correct profile after curing.  

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Fantastic pictures and information about Walker body construction.  My apologies if the next suggestion offends.  Fisher suggests using "friction tape" between wood and metal braces to eliminate squeeking.

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38 minutes ago, Tinindian said:

Fantastic pictures and information about Walker body construction.  My apologies if the next suggestion offends.  Fisher suggests using "friction tape" between wood and metal braces to eliminate squeeking.

Not offended at all.

 

That will also work if you can get the strips of friction tape to stay put while you get the parts screwed in place. Not a job for a cold garage. 😉 

 

I just duplicated what Derham did with their waxed linen. I  cut up old bed sheets the wife was going to get rid of and melted down candle stubs. No squeaks, squawks, or any noise from the metal to wood contact areas, including using it under the edges of where all body sheet metal attaches to the  framing. And it doesn't absorb moisture like Walker's graphited asbestos paper. Even though there was a lot of wood rot in the body framing, there was no corrosion wherever Derham used the waxed linen,..... unlike Walker's graphite/asbestos paper where there was rust under all  the steel reinforcements. 

 

Paul

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On ‎4‎/‎25‎/‎2019 at 6:41 PM, Brooklyn Beer said:

Has pocket hole joinery been attempted repairing wood? 

If you mean biscuit joinery, no need. Properly fitted scarf joints, with good quality slow-cure epoxy are very strong. The glue-joint boundary area actually exceeds the wood strength. Adding biscuits just complicates fitting the joints and does not increase the joint strength. That's why we used them to strand up to the high stresses boat are subjected to that biscuit joinery type woodwork is not. The stresses on cars are more like boats than houses. The mindset of how to design the framing and how to properly repair car wood to withstand being bounced down rough roads  with hundreds of pounds of passengers is very different from a house carpenter mindset.

 

Paul

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6 hours ago, Tinindian said:

Pocket hole joinery and  biscuit joinery although related, perhaps, are different.

 

https://en.wikipedia.org/wiki/Pocket-hole_joinery

 

https://en.wikipedia.org/wiki/Biscuit_joiner

Thanks for posting that, TI.

 

Joints with just screws holding end gain to side grain are far too weak and will allow movement at the joint, which will eventually weaken it more. When joining wood at right angles to the grains, such as posts to body sills and roof rails,  mortise and tenon  joints were often used. That type joinery gives side grain to side grain for gluing and a far stronger joint that won't squeak  like a screwed together joint.

 

Paul

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Could be a good reason to finally buy that mortising and tenon jig for my table saw but I am sure I could figure out a way to use the sled on the router table. Works well with cabinet door frames but maybe the wood on the car would be too big for it.

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17 hours ago, Brooklyn Beer said:

Could be a good reason to finally buy that mortising and tenon jig for my table saw but I am sure I could figure out a way to use the sled on the router table. Works well with cabinet door frames but maybe the wood on the car would be too big for it.

Save your money on fancy jigs and accessories. Most of the mortises used in body framing are basic "open through type".   Those jigs and a router are ok for house hold type carpentry, but won't work well for the thick white ash wood used in autobody framing.  A good crosscut saw, Wooden mallet and a good set of carpenter chisels work better . For instance, where posts attach to the body sills, you make two cuts in from the edge of the sill the width of the post and chisel out the waste. The post then has a step that rests on the inner edge of the mortise in the sill. Same for many of the posts fitting to roof rails. Then the post would be glued and one wood screw in from the outer surface through the tenon into the sill to hold the tenon into the mortise as the glue dried.

 

That wood screw through the tenon is also handy for first fitting the new wood in, making sure the sheet metal fits back, then it can be unscrewed to glue the joint for final assembly, once it's certain that everything fits together

 

Paul

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  • 1 year later...

Certainly would suggest purchasing this book:  Practical Car Restoration by charles wilmarth III  The top wood had to be rebuilt as you can see. Believe you would learn and be encouraged. He drove it from the West to the 2002 Trek.  VERY interesting.  Check Amazon, ebay, etc. the book is available.
EDIT:  I thought a later post; I need to read date of post.  ANYWAY~~~~~~~~~~~ a good read !
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7 hours ago, Fonie said:

Hello paul: in need of wood top for my 1929 franklin. Email is biscit216@gmail.com.

 Sorry Fonie. I don't make wood kits or parts from the bodies.

 

The body framing was not built like the other parts of the cars to be interchangeable. Each body was built by one carpenter. Then the sheet metal shop fit the sheet metal to whatever that ended up as. The only parts that were jig built were the doors. Too much variation in the other body parts that parts patterned from one body you could expect they will fit properly with another of the same body style. Plus, there were mid production changes to deal with problems that turned up.  

 

Even year to year the same body styles that look the same had changes not easy to see. I've re-wooded  28 12B and a 29 135 Walker Victorias. It was assumed that other than the curvature of the corners of the rear side window reveals, they were the same body. Except that the 29 is one inch longer from the rear window frame to the dash board header. Which means doors, body sills, and roof rails are different.  

 

So I only work on a car in my shop and fit new wood to that one.

 

Paul

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