Jim Thomas Drawings

[wrist_pin]

Hi all,

There was talk on this thread about some drawings made by Jim Thomas.

I know the thread is 10 years old but maybe someone has them.

Scale Drawings Cobra Mk II Frame +

Did any of you get the set of 5 drawings?

For that matter, did anyone create CAD drawings (.dxf or .dwg) from them?

I'm in the market for a copy of the set and don't mind paying a fair price.

Does Jim Thomas still sell the 289 version? How would I get a hold of him?

Forrest

[KarlCSX2498]

Hello, I purchased a set of those drawings in approx. 1980. I sent them up to Nick at Acton Custom to be transferred over to CAD a couple years ago. I will ask Nick what he has been able to do with them.
Later, Karl

[wrist_pin]

Thanks Karl, for the offer of help. Good Luck! I'm more interested in a copy of the drawings than a cad file.

I found a 2001 email address for J Thomas on the interWeb. Based on where I found it, I think it was for him. Anyways, I tried to email him and it came back to me as undeliverable.

Using a 14 year old email address? It was a shot in the dark.

Forrest

[KarlCSX2498]

Hello, Nick says he has most of the drawings transferred over to CAD. I will ask Nick if we can get a new copy of the drawings for you.
regards, Karl

[mickmate]

I haven't talked to Jim in a long time I'll have to see if I can dig up a number for him. Karl has been in touch and we'll arrange a copy for you.

[LMH]

Forrest, are you thinking of building a chassis from scratch? Got to tell you it's quite an undertaking to get right w/o a fixture jig.
Larry

[ScratchBuilder]

Chuck has built a couple 289s n sells plans for them: . WEB SITE INTRODUCTION

[MAStuart]

Larry a good set of plans is more important than a jig. You can build a nice straight frame without a jig. Takes patience and a lot of measuring. A good jig would be nice if you are going to build more than one or two. Keep in mind that when you weld it will pull the tubing all over the place. This will happen with a jig . You have to learn tweek thing as you go to keep things straight.

I build thing from others plans. Most plans have problems. From what I have seen there are no cobra chassis plans that don't have problems with the numbers or missing numbers. They just don't add up.

If you could find a set of plans with good numbers it would easy to build accurately with no jig.

Mark

[MAStuart]

Originally Posted by wrist_pin

Hi all,

There was talk on this thread about some drawings made by Jim Thomas.

I know the thread is 10 years old but maybe someone has them.

Scale Drawings Cobra Mk II Frame +

Did any of you get the set of 5 drawings?

For that matter, did anyone create CAD drawings (.dxf or .dwg) from them?

I'm in the market for a copy of the set and don't mind paying a fair price.

Does Jim Thomas still sell the 289 version? How would I get a hold of him?

Forrest

I looked at these drawing in the link . The rear spring tower does not appear correct . The two side plates that the half shafts go threw should have an almost 180 degree bend that come down to the bushing that he rear diff mounts to. This is all welded together to make things stiffer in that area.

[LMH]

Originally Posted by MAStuart

Larry a good set of plans is more important than a jig. You can build a nice straight frame without a jig. Takes patience and a lot of measuring. A good jig would be nice if you are going to build more than one or two. Keep in mind that when you weld it will pull the tubing all over the place. This will happen with a jig . You have to learn tweek thing as you go to keep things straight.

I build thing from others plans. Most plans have problems. From what I have seen there are no cobra chassis plans that don't have problems with the numbers or missing numbers. They just don't add up.

If you could find a set of plans with good numbers it would easy to build accurately with no jig.

Mark

It can be done, of course. But I've seen more than a couple frames built from plans that are just too far out of square to work. It all boils down to the
person making it. It's an undertaking few really realize until they actually get into it. I'm speaking of replicated original type frames.
For me, I have access to a jig but I'm only interested in one frame.
Larry

[mickmate]

As Mark (MAStuart) says they all vary. Dimensions are all off the frame so if you start with good frame rails it's all doable. On the 289 frames and plans I have seen issues with lower control arm holes which raise hell with leaf spring geometry. That is why I make a lot of adjustable or comp style lowers for bent originals or replicas with incorrectly located mounts. Fortunately for 289 builders we have a lot more options on spring length or even adjustable trunnions. Other common issues are frame width anomalies that don't jive with original tank sizes, leaf spring channel mount heights that translate into diff mounting issues. If you have paid the money for an original style diff you pay again in sweat getting it to fit in there. We have some creative solutions there too with Jag pumpkins actually fitting even though we're told they won't.

[MAStuart]

Hi Larry What I am getting at is how do you know the jig you are using is an accurate jig of an original. There will be problems in just building a jig accurately when welding it together . Most people would be shocked to see how much a weld can pull a joint when lets say a piece of tube gets welded on one end and the other end is 3 foot away. I have seen where a part was jigged up and welded and after the part was taken out of the jig it is imposable to put back in the jig. I would think that the original cars chassis varied from car to car for this reason alone. If the jig was built off of an original car how does anyone know that that car didn't have a crash in the past and have small twists and bends that cant be seen?

Mark

[LMH]

Definitely an issue, even in a jig but that underscores my point. It's hard enough to get it right in a jig. Built on a table compounds the problem. It can be done right for sure but it's a lot more work out of a jig. For some owners though, that's where the hobby is... the build. I don't want to pee in someones Cheerios about building their own chassis. I just want to point out that there's a lot more to building it than it looks like from a set of plans.
Larry

[cobrakiwi]

Building a frame from scratch is a large project, having something to copy or good plans is a must.
I would follow ScratchBuilders advise and contact Chuck.
I have built a few 427 type frames now, believe me, it is a lot of work but also very satisfying if you can pull it off.

One of my build links, New Build

Here is a pic of one of my 427 frames I just completed and dropped off to powder coating last week.

IMO, It will make your task a lot easier if you have all your suspension and body first.

I say have a go and good luck!

[MAStuart]

As much interest there is in building original chassis you would think the info would be easy to find . Having access to an original would be a big help. Do you think we could start a thread on the Originality forum to maybe get some input from original car owners ? So that we as a group could come up with a set of plans for at least the basic frame to start.

Mark

[MAStuart]

Hi guys. Not wanting to burn any bridges or bad mouth anyone. But has anyone tried to build off of Chucks plans? I have been looking for someone else that is building off his plans from the time I started my scratch build coupe project. If you buy all his info it is expensive. The info is invaluable to build a coupe but there is a lot of problems with the drawing. Even with the drawing there is a lot of head scratching because of missing info. If you contact Chuck about a problem he will get back to you to try to help. He has revised some drawing when I called problems to his attention.

Mark

[LMH]

I haven't seen them in real life but I have heard Chucks plans are accurate and complete. Would be nice to hear from someone who has actually done one from his plans.
Larry

[MAStuart]

Larry I am trying. If the info was good and complete I would be done. I have gotten 3 of the packages for the coupe at a cost of $1800.00 plus shipping. He has more packages coming like the wire harness. I think it will also be a $600.00 set of drawings.

Mark

[LMH]

Originally Posted by MAStuart

Hi Larry What I am getting at is how do you know the jig you are using is an accurate jig of an original. There will be problems in just building a jig accurately when welding it together . Most people would be shocked to see how much a weld can pull a joint when lets say a piece of tube gets welded on one end and the other end is 3 foot away. I have seen where a part was jigged up and welded and after the part was taken out of the jig it is imposable to put back in the jig. I would think that the original cars chassis varied from car to car for this reason alone. If the jig was built off of an original car how does anyone know that that car didn't have a crash in the past and have small twists and bends that cant be seen?

Mark

I really don't know if the car copied for the jig was ever in an accident or not. I know it was built using an original car though, during it's restoration. I'm not to a build point that I can say everything came into adjustment perfectly, so as for my frame, I can't say everything is perfect. Jeff Gagnons car came out of the same jig though, so he could say better than I.
Larry

[LMH]

Originally Posted by MAStuart

Larry I am trying If the info was good and complete I would be done.

Mark

Oh, you are building from Chucks plans? Cool! Didn't know that.
Larry