Control rods. Riveted U.C.
 

My idea here is to make this thread a resource of info for the various control rods in the standard MkI U.C.
Most of the rods are medium tensile 7/16" dia. with BSF threads (the throttle control rods are smaller)
If I have any measurements wrong please advise, and I will edit my mistakes.
It maybe be that correct lengths are in a parts book, and if so, someone might like to put all of them up here.
Until then, here are the finished cut lengths of some, to start with;

There are essentially eleven rods;
Five for the brakes,
Two to hold the power unit to the rear plate,
Two clutch rods, and
Two throttle rods (1/4" dia.)
All rods are B.S.F. threads.

The LONGEST brake rods are both the same (TL5014) length at 2153mm overall length, with 32mm of thread at each end.
The transverse rod (TL 2332) is 646mm overall length with 45mm of thread at each end.

The front clutch rod (TL2328) is 1125mm long overall length, with 60mm of thread at one end, and 40mm at the other
The rear clutch rod (CTL7111) is 1078mm overall length, with 32mm of thread at each end.

The two throttle rods;
the long one is 1040mm overall length, with each end having about 25mm of thread. (rear?)(CTL7112)
the short one is 973mm. thread as above (front?)(CTL2744)
Which ever is the rear one may vary due to different throttle bell crank arrangements with 21 and 24 stud motors. The front rod is the same in all applications.

The engine tieback rod (TL 881) is 585mm overall length. It has 40mm of thread at one end, and 110mm at the other.
It has a kink at each end, about 100mm in.

With regards the cam control rods, the length of the rod from tip of the thread to the center of the pin (long clevis end) is 687mm. this includes the 35mm of thread. This would be the total of CTL 2881 and CTL2882 (1941 parts book) if both were riveted together as one assembly (and any adjustment would be made at the small clevis end. This is here so that someone can make up their own rod assemblies using original clevises. I hope its all clear?

The short brake rods are 250mm overall length. I have 35mm thread on one end and 40mm on the other. I made this rod some years back so these dimensions will need to be confirmed.

Well done Lynn.....this will help loads of folk, myself included ! i am missing the short rods that go from the brake pedal to the steering linkage bundle at the bottom of the steering column.

the steel used is it anything special ? reason I ask is the longer rods must get some pretty load on them and some steel is more flexible than others.... i have always wondered about this.

Rich
 

I'm not that sophisticated, I arrived at medium tensile, because it aint mild and you have to be able to cut a thread into it. Are there any metalurgists on the forum that can do a rockwell test?

I only put in the time and effort because I thought it might help some bloke on the other side of the globe wot talks funny :D.
I will get to the short rods (they are the only ones left) Are you in a hurry?
I'd like to hear from someone with an original engine tie back rod. The thread on mine seems very long. Is it normal?

Lynn, Thats all very handy info mate. the engine tie rods do have a long length of thread because you have to be able to wind the nuts a long way on the bars. This is so you are able to jiggle them through the hull and then through the block, does that make sence to you ?
TTFN
Shaun

no hurry at all Lynn..... and as always your efforts here are greatly appreciated.

Shaun, Rich,etc.
 

Richard, the short rods are there, but as stated need someone to check the details, as my sample, I made, and may not be accurate.
Thanks Shaun for the explanation. I havent got that far yet, so didnt know.

Sorry to resurrect the thread Lynn... The lengths quoted, is that minus the clevis pieces, ie it's the length of the actual rod rather than the assembly ?

Just getting ready to make up the front to rear brake rods, thinking about material, I cut the remains of one with ease using a blunt hacksaw today, my thoughts are if the brake works by being pulled on by the rod rather than pushed, then mild steel might be ok to use as it should be ok in tension.... Different gravy if they are pushed on though.

I made some using these dimensions and they were for the rod only, no clevis.

I ordered slightly higher grade steel. Mild steel today is generally crap. It wasn't much more money but seems to be better. For the life of me I can't find the invoice with the material name and number. If you ring a wholesaler and ask for some advise it would pay off. You'll be slightly limited in that you want 7/16 but the one I got has a little chromium in it as it's used it the petrochemical industry.

Ben

Steel Grade
 

Probably was 4140 -medium tensile , you can also get '' free cutting '' steels which cuts and forms threads better than mild steel grades.

I was only ever talking about the finished length of the rod, including the threads and nothing extra. I'm sure I have already covered this. (see line 5 first post)

The rod is a medium tensile, which is what you would require. You have to be able to put a thread on it, but you want it strong.
Free cutting mild steel has a lower tensile strength than mild steel (mild steel doesn't have a spec) It is higher in lead content to make the thread cutting easier. It is not suitable for this job.

On the thread cutting;
It is easy to screw it up! (start it crooked)
When you buy your steel for your long rods, and you have cut them to length, you have only one shot at it.
The best way to do it (unless you have access to special thread rolling gear) is to put the rod in a lathe (chuck) and your die holder against the spindle of the tail stock.
This helps you to keep it all square for the thread cutting
You can then "feed' the die with the tail stock, while turning the chuck by hand (maybe easier swinging it with the chuck key)
It the case of the long rods, careful planning to support the rod is required (maybe put it in a pipe that fits in the hole through the headstock and supporting the other end with a stand or timber frame or what have you) Make sure the lathe is isolated (switched off at the main) or serious damage is likely.

If anybody needs these, I can do them as required. I would suggest EN8 and I would thread them in a capstan using a Coventry diehead, this would give perfect threads.

Adrian, can you explain the EN system? I remember (as a young fella) the steel crank to have for a Lotus twin cam was made from EN40B.
If I was over there, I'd be taking up your offer. :note:

Lynn, it's the old British system BS970, superseded some years ago by a newer version with different codes.

Freecutting MS that you mentioned was EN1A and is now 230M07 where the 07 indicates carbon content, i.e 0.07 %. EN8 is now 080M40 so 0.4%. Carbon content is a good indicator of a steels ability to be hardened.

EN40B is now 722M24 and is a 3% chromium molydenum nitriding steel that when nitrogen hardened (nitriding) has a very hard wear resistant case and a tough (60tons) core. Ideal for a crank!

Just thinking out loud, how much load can you put on the brake rod in reality? Do you think the small lever that is the brake pedal has sufficient length to pull a set of threads ?

I am only asking as I have access to a load of mild rod I understand the need for a greater tensile if the rod worked in compression:)

It's a shame that I need to go order some EN8

Mild steel rod
 

I don't want to come in late and blow it to bits but I used shiny mild steel rod for my long brake rods, I didn't think that the threads would ever pull off or the mild steel rod to be inferior, the clevis's are screwed on about an inch and a bit with a locknut so its not like they are compromised by being held by 3-4 turns. I cut my own thread using hand tools and the rods are working fine. Also made the engine to rear plate and clutch rods with mild as well as the accelerator rod. When cutting the old rods I replaced (as parts were excessively rusty, I cut them with a hacksaw) then re used sections I did not notice any increase in hardness. My carrier has been getting around fine. Im not saying take my advice as im just a mechanic, but if you have a supply of mild it would poss do.

Lew it may be fine with mild steel (aren't some LP2 rods 1/2 inch?) but in this day and age of blame and litigation, I wouldn't knowingly be using an inferior component in my brakes.

Richard for the money you have spent on your carrier already, the rod is very cheap.

Adrian, Thank you for the explanation.

That's a contradiction!

I'm sure mild steel would be fine though, normal bright mild steel is EN3B, it has a tensile strength of about 80% that of EN8.

My thoughts being if the brake rod pushed the shoes on the rod would flex, and the need for higher tensile steel would be required.... Of course I could be way off as my understanding is negligible in this area.

I have dropped you a PM Adrian.

Richard, All the rods pull, none push.

Can some one give me details of where the kinks are in the rear clutch rod
(CTL 7111 - 1078mm long) and maybe the angles?
Thanks in advance.

CLUTCH REAR ROD KINKS.
To answer my own question:
With the rod installed the rear threads transition to plain rod sits approximately 25 mm rear of the bell housing line.
While the rod is in the above position the rear kink is in line with the vertical rod of the throttle bellcrank.
The front kink is about 80mm forward of the center exhaust manifold bolt.
The front and rear lines of the rod are parallel.

Clutch free board adjustment is achieved at the rear clevis. (it would be difficult to rotate the kinked rod)

I thought I'd drag this back to the top for Seb.