Fabricating Seat Spring assembly

[MikeC5]

I thought this might be of interest to anyone with a '25 vintage DB with rusted out seat springs.  I'm trying this on the seat bottom springs since the framework is 2 dimensional (unlike the seat backs which require some 3D bending).  There is at least one Model T/A parts vendor that can make seat springs to order but it is very pricey.  

 

The tool you see here is the Harbor Freight tube/Rod Bender (https://www.harborfreight.com/compact-bender-38470.html).  It looks identical tot he Eastwood model at less that half the price and seems pretty robust.  The tubing I'm using here is 1/2 x 1 rectangular tube, 0.062 wall.  In order to get this to smoothly bend without buckles, the inner diameter dies were modified as shown in the photos (there are Youtube videos showing similar).  So you do need access to a metal lathe.  Also, in order to make things bend easier, I heated up the tube to bright orange with an oxy-propane torch with rosebud tip.  I do have AutoCad drawings for the dies I machined if anyone wants more detail.  I also had to buy some larger diameter stock to make dies for the larger radius bends.  

 

The bottom frame of the original spring assembly is shown first.  Please note that the original has a crimped in tack strip for holding the seat cover on.  This was too complex for me to reproduce so I'm planning to use hog rings.  

 

 

[nearchoclatetown]

Looks good and strong.

[trimacar]

Your base looks great!  I assume the top rim of the cushion is edge wire, a spring steel used for seats?  I agree That the commercially made seats are a little pricey…

 

[MikeC5]

Thanks guys.  Yes, the top will be edge wire bent to a somewhat more rectangular shape and I'll be using coil springs of pretty close to original diameter.  The number of coils on each spring increases toward the forward end of seat (thickest at forward edge and tapers down by roughly 3 inches at aft edge)  I'll show some additional photos of original spring assy.

[Mattml430]

Very nice job it looks great. I remember doing the ones for the roadster, they were tricky to. I had to stick some nylon inside my square tube and then cut a bit out of it so I could staple the leather to it. I think it also helped the tube keep its shape on the corners. But yours looks great. 👍

[MikeC5]

Thanks Matt.  Here is the tube all welded up.  It will need just a little tweaking to lie flat.  The next step will be to weld on the u-pieces that will serve to crimp onto the edge of the perimeter coils (at bottom of spring).  This and the tack strip were all accomplished with one piece on the original seats.  I don't think the piece was extruded but bent from flat sheet (~ 0.040" thick).  I'd like to see the tooling they used...  I'll be using this u-shaped piece which is 0.125 opening but I could only find them 1" long.  I'll be cutting them back to 1/4 to 3/8" and then will weld the bottom of the 'u' to the inside edge of frame.

 

 

Edited April 21, 2022 by MikeC5 (see edit history)

[MikeC5]

Front seal frame completed.

 

 

[Ron Lawson]

3 hours ago, MikeC5 said:

Front seal frame completed.

 

 

Beautiful workmanship  Thank you for sharing These little things help others that become stuck with a problem 

[MikeC5]

Thanks Ron!  Sometimes I'm envious of those Model T guys where almost anything you need is just a few clicks away....  Not much challenge it that though...

[Ron Lawson]

1 hour ago, MikeC5 said:

Thanks Ron!  Sometimes I'm envious of those Model T guys where almost anything you need is just a few clicks away....  Not much challenge it that though...

Same this end Mike. The DB 2249 series Senior is a rare car anywhere and mine with an Aussie touring body is one of 250 that were made so I can feel for you. We have no choice to become "Industrious" and make our own parts 

[MikeC5]

A small update, the perimeter spring retainer is welded in place on the front seat base.  The channel is easily crimped over the edge of the springs.

 

 

[Machinist_Bill]

Well Mike, if you ever have problems keeping a job as an Engineer, I can get you started on being a Machinist! 😁

Very nice work!

 

Bill

[DB26]

Beautiful 

[MikeC5]

Thanks Guys.  I think the biggest challenge will be making the pleated leather seat covers.  I've got a pile of Youtube videos, some books/articles, an old Singer 111 walking foot sewing machine and scraps of the original seats to get me going.  It should make a good winter project.  I have to start shopping for hides..

[MikeC5]

Rear seat frame completed.  The welding did result in a bow to the forward tube.  The first picture shows the 'stress relief' fixture.  I heated the u-channel side with oxy-propane to orange hot then air cool.  Straightened it up pretty well.

 

Edited June 10, 2022 by MikeC5 (see edit history)

[Mattml430]

Bloody beautiful!!

[MikeC5]

Thanks Matt.  I'm having to do some modification on the springs because the ends are too large in diameter.  Will post detail later.

[cutdown]

Mike. I suggest you make the first seat cover out of vinyl in order to get it right.  Then get some hide and make the real one. Wish I had one of those sewing machines. 

[MikeC5]

Yea, that's a good idea.  I was thinking maybe canvas.  Would vinyl be better for practice?

[cutdown]

My seat is made from Lyonide Moose Black. I purchased some more of it to finish the seat better that it was [ as per previous post of mine ] and got enough do the whole seat squab again using the fold stitching technique which was in the video you sent on to me. 

Once you have done that, you may decide it looks so good  you will be happy to use that permanently.

[MikeC5]

I looked and it doesn't appear the Lyonide Moose Black is available in the USA.  I made a little more progress; attaching springs to the perimeter frame.  I then added a little weld where the crimped sides of the u-channel meet.  

[cutdown]

Looking good.

 

BTW. How many people do you have helping getting your seat done. Hope you have enough safety glasses for them all.

 

Dereck

Edited June 30, 2022 by cutdown (see edit history)

[cutdown]

Mike. That vinyl I used had a textured pattern on it rather than dead smooth.  Looks a little like leather so you ought to be able to get something similar locally.

Have another question for you on my original seat thread.

[MikeC5]

Got a little further along.  I was able to do a pretty decent job bending up the edge wire for the top edge of front seat bottom.  I ended up welding the ends where they meet and it seems it should hold up well.  The one thing I can't find anywhere (on-line) are these paper clip-looking links that tie spring to spring in several areas.  I may have to make my own....  

[MikeC5]

Progress has slowed.  I'm waiting on back order for more spring edge wire...

 

[trimacar]

Looks like nice work!  Did it originally have the wire across the top of the springs as pictures show?  That's unusual and would make for a very stiff seat.  I understand the wire on the bottom to position the springs.

 

Usually there are a couple of diagonal wires, from rear bottom to front top, to help keep the spring assembly from collapsing backwards.  On some cushions they go both ways, also having front bottom to rear top.

 

You might try Three Rivers Supply in W. Homestead Pa. they usually have edge wire.  PerfectFit in Oregon also carries it.  As to the loop clips, never seen those for sale so making your own probably the best, they could be just mild steel, as the edge wire is so hard to bend in tight curves.  A lot of cars used short extension springs to connect the tops of the coil springs.

 

I have hundreds of pictures of seats I've worked on, but hard to find one which shows the diagonal wire I discuss, this gives you the idea...

[MikeC5]

Thanks David,

I am following the original seat spring wire pattern as closely as possible.  The diagonal wire makes sense.  I'll have to see if I can fit something like that in.  I did find another source for the edge wire and am hoping it is the same diameter as what I have now (which measured 0.148" OD).  It comes back to what is 9 gauge?  It depends on what standard they are using...  The springs to tie together the tops of the coils may work.  I'll have to see what I can find.

[MikeC5]

A little more progress.  I thought I would try an aircraft mechanic trick by using safety wire to tie the springs together on top.  This is 0.032" diameter stainless steel wire.  I'll put some blankets over it and test it out for a while...

 

[cutdown]

Someone mentioned that tying the top of the springs close together may make the sea harder. the original has those paper clip look alike retainers which allow the springs to operate independently.

Below is a picture of my original which if you look closely, you can see the diagonal support springs mentioned above from top front to bottom rear and vise versa in the middle . They stop the top of the seat from moving out of line in the forwards backwards direction. you can also see how the links between the top of the springs are situated. They tie together the middle and back row of springs sideways, and all of the springs in th eforward bacwards direction.

 

Good like rebuild there mate.

[MikeC5]

Thanks for the input.  I took another look at the original seat springs and I do see some of the clips are longer than the distance between springs (allowing some movement), but some not.  They don't have much give if you try and pull them apart.  It will be some time before I get around to covering the assembly so if it is too stiff, I'll be able to change the plan.

 

Edited August 23, 2022 by MikeC5 (see edit history)

[MikeC5]

I did add some diagonals as you suggested Cutdown.  I was able to get a couple of drives in with the new spring base and some blankets over it and it seemed pretty comfortable.

[MikeC5]

Thanks John.  Feel free to ask for help when you decide to tackle it.  I did get some of my supplies from Albrights.  

Edited November 11, 2022 by MikeC5 (see edit history)

[MikeC5]

Here's an update showing the 1/2 inch hardware cloth (vinyl), canvas (instead of burlap), horse hair /rubber and then jute added to the spring assembly.  I'm following Hugh's playbook and it looks pretty good so far.

[Mark Gregush]

Looking good! The link that follows shows some information about installing the upholstery: Installation Videos (classtiqueupholstery.com)

[MikeC5]

Thanks Mark.  I like the idea of using the 2 x 4s to compress the seat bottom for attachment of cover.  It appears he compresses it 2 - 3".  I made my bottom spring assemblies to match the uncovered spring height of the originals.  I'm not sure if there is enough left of the orignal covers to tell how tall the side skirt should be (a clue to how much the springs were compressed).  Can anyone measure the approximate hieght of the seat bottom at forward and aft end of cusion?  This would give me an approximate number to work towards for finished cusion height.

[Mark Gregush]

My question would be, is that 1/4" hardware cloth going to allow enough flex to the seat, or will it be like sitting on a board? 

[MikeC5]

This is the stuff I used https://www.walmart.com/ip/Tenax-Hardware-Netting-15-ft-L-2-ft-H-1-2-x-1-2-in-Mesh-Plastic-Black/468782704.  It's not real hardware cloth.  It's nylon (?) string coated with plastic.  It's really is pretty flexible.  I think it's the same stuff Hugh used on his '25 Buick.

Edited January 6, 2023 by MikeC5 (see edit history)

[MikeC5]

I'm trying to get the spring padding looking right and am not sure what to do on the upper portion of seat back.  The cover has come up and over and have a rounded look like this photo from a restored car.  I think using cotton will give the smoothest look here but it's difficult to get a consistently think layer in there.  Any other ideas?

 

[MikeC5]

I finally bit the bullet and ordered up the leather.  I'm still experimenting with getting the bend around top of seat back so it won't wrinkle the tuck & roll.  I'm using leftover top material that is a vinyl backed with some kind of cotton (I think).  It's not as pliable as the leather samples I've gotten, nor does it stretch.  In this photo, the 3.5" pleats are stuffed with 2" think cotton batting that is folded over in 2 layers (so 4" total).  I then compress it down into channel tins and insert into the pleat (this is a good video of how it's done https://www.youtube.com/watch?v=re4ybTju-t4).  I'm happy with how the pleats come out but am concerned about getting them to bend around the top of seat back.  The photos shows what happens when trying to bend a test panel around the top.  I believe this will be not as bad with leather (a test panel will be made) but I'm looking for ways to minimize the problem.  Ideally, if I could taper the thickness of stuffing to little or none around the bend, it would help but I'm not sure how you would deal with the extra material (since it isn't bulging out).  Adjusting the pleat dimensions and using less stuffing thickness also helps.  I tried using 3/8" jute instad of cotton and it does improve things.  One suggestion I have received said to increase the radius of curvature of the bend, but I'm not sure I could change it enough to make much of a difference without radically chaning the seat back shape.  Anyone been there, done that, with some suggestions?  

 

Edited March 6, 2023 by MikeC5 (see edit history)

[jan arnett (2)]

Have you tried leaving it in the sun or heat lamps.  I have used hair dryers.  Don't use a heat gun as then may get too hot.