Author Topic: TS Foot Board tubes  (Read 1416 times)

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Offline Marcus

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TS Foot Board tubes
« on: 28 Mar 2022 at 23:37 »
Hi Everyone,

My 1925 frame has had its tubes that the foot boards are fixed to removed and so I'm hoping someone wouldn't mind measuring how wide they are please and if the are the same length or different lengths front and back.

Thanks
Marcus

Offline Jim

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Re: TS Foot Board tubes
« Reply #1 on: 06 Apr 2022 at 23:55 »
Hello Marcus, first there is a bit of 3/4 od tube about 5 inches long  in the frame and then a piece of 7/8 od tube on each end which is 6 1/2 inches long, front and rear appear to be the same, and a 1/4 rod through the middle to hold it together. Hope this makes sense, regards Jim

Offline Marcus

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Re: TS Foot Board tubes
« Reply #2 on: 07 Apr 2022 at 00:09 »
Hi Jim,

Thank you very much for that information, below is what remains at the front.

Am I correct in assuming that the 5 inch piece of 3/4 tube is brazed into the frame lugs and then the 2 pieces of 7/8 on each side are just slid over and clamped by the 1/4 inch rod with a cap on each end of the 7/8 tube.

Cheers
Marcus

Offline Jim

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Re: TS Foot Board tubes
« Reply #3 on: 07 Apr 2022 at 03:45 »
Hello Marcus, I think the 3/4 tube isn`t brazed so it can be removed if it is bent (don`t know) and the 7/8 tubes do fit on it like you said, regards Jim

Offline Marcus

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Re: TS Foot Board tubes
« Reply #4 on: 07 Apr 2022 at 05:09 »
Thanks Jim,

I assumed that the 3/4 tube was brazed as the remains at the front seems to be, however I will have a really good look when I remove it. I was worried that if the 3/4 tube is sliding inside the 7/8, that over time it might work its way out of the lug into one of the side tubes. But lets see what I find.

Thanks again for your help

Kind Regards

Marcus

Offline Hutch

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Re: TS Foot Board tubes
« Reply #5 on: 09 Apr 2022 at 06:54 »
Hi Marcus,

I concur with Jim's dimensions and findings. On the frames I have seen the front 3/4" tube does not appear to be brazed. It was a tight fit on one I pulled apart but that was partly because it was bent.

The 1/4 rod is about 17" long (measured on an original) and the threads at each end are 17/64 25tpi. The nuts are 7/16" across the flats but I cannot be sure they are original. The end caps protrude about 3/16" past the end of the 6 1/2" long 7/8" tubes. I can take a picture of an original if you like (I have only ever found one!).

cheers

Hutch

Offline cardan

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Re: TS Foot Board tubes
« Reply #6 on: 09 Apr 2022 at 07:06 »
The 1/4 rod is about 17" long (measured on an original) and the threads at each end are 17/64 25tpi.
That's interesting. Was the thread rolled on the 1/4 rod, like a giant spoke?

Leon

Offline Hutch

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Re: TS Foot Board tubes
« Reply #7 on: 09 Apr 2022 at 08:46 »
I (edit- think I can) see where you are coming from Leon and a good point :-). I re-measured my "original" 1/4" rod and it is 1/4". The threads appear to be 1/4" not 17/64". - so a 1/64" (15 thou or so) missing from the tips of the thread form?. I will have to investigate further to see if it is a rolled thread - I'm not sure.

Or maybe it is not an original rod as I assumed - tho' it does have the patina of an original and is even bent for good measure. Pitch does measure 25 tpi and not 26 tpi. (Taps and dies shown are the club ones for 17/64 25 tpi and I also used a thread gauge for good measure).

The hole in the (presumably) original end cap is 17/64".

I have no idea what year or model of 2 3/4 hp Douglas the rod came from. Maybe war effort and Douglas had a shortage of 17/64" rod? :-) .....just joking.

Maybe 1/4" was deemed to be near enough or originally nickel plated 5 thou or so for corrosion prevention and that made up part of the missing 1/64"  ?. No evidence of plating on the rod I have - but it is not unusual for it to be long gone!

Maybe some other forum members have an original they can measure for comparison?

If one was to  make a reproduction with 1/4" rod and 1/4" 26 tpi BSCY threads I don't think anyone would notice! :-)

cheers

Hutch
« Last Edit: 09 Apr 2022 at 11:06 by Hutch »

Offline Marcus

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Re: TS Foot Board tubes
« Reply #8 on: 10 Apr 2022 at 06:42 »
Hi Everyone,

Thank you very much for all the information. I now realise by looking at a couple of bikes here and also the photos of the frame currently for sale on the Facebook page that what I thought were the original tubes that had been cut off at the front are in fact the 5 inch long 3/4 tube that has 1/2 long 7/8 tube sleeves fitted over it hard up against the lug on the frame. The front lug is only 2 inches wide while the rear lug is 3 inches so the 7/8 half inch sleeves end up making it 3 inches and then 6 1/2 inch long 7/8 tubes can be used both front and rear.

I cut a 5 inch piece of 3/4 tube and that is a tight fit in the rear lug, I will take it with me this week to get some 7/8 tube that is a good fit, I think 1.6mm wall thickness should work well but want to make sure and then will press the 3/4 tube into the frame lug.

Hutch,
I will probably end up using 1/4 rod as I have some and 17/64 is not available, If you wouldn't mind taking a photo of the end cap from the side, that will be much appreciated as I can turn some up. I was going to use a suitable size cup type core plug but would much rather match what Douglas did originally.

Thanks again guys

Marcus

Offline Hutch

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Re: TS Foot Board tubes
« Reply #9 on: 12 Apr 2022 at 02:20 »
Not quite in focus but hopefully good enough for you to copy?

Offline Marcus

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Re: TS Foot Board tubes
« Reply #10 on: 12 Apr 2022 at 02:30 »
Perfect, Thanks very much for that, I will knock 4 out to suit the tube.

Cheers

Marcus

Offline Marcus

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Re: TS Foot Board tubes
« Reply #11 on: 15 Apr 2022 at 06:00 »
Today I turned up the end caps and made the clamping rod. I didn't get a chance to get some 7/8 tube before the weekend so that will have to wait until Tuesday.

Thanks again everyone
Marcus


Offline Hutch

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Re: TS Foot Board tubes
« Reply #12 on: 16 Apr 2022 at 04:23 »
Looks good Marcus,

I had two original (or at least ones that were bent, rusty and generally mangled) footrest tubes so I needed to make up some more. The only scrap 7/8 OD tube I had lying around was off an old Landrover steering drag link. It was a bit bent (due to off road adventures) so was not going to be used on a Landrover again. It was also a bit thick in the wall so I just machined the ends out to suit the caps and 3/4" tube. Only concern I have is that if the bike comes to grief and the foot rests / boards get hit then these tubes probably won't bend but something else will (!) - like the frame  :-(. I guess I could bore them out all the way but that would involve making up a boring bar for the purpose......or find some tube with the correct ID.

cheers

Hutch

Offline Marcus

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Re: TS Foot Board tubes
« Reply #13 on: 16 Apr 2022 at 05:18 »
Hi Hutch,

Here in Auckland we can buy 22.2mm OD tube (7/8") in 1.6mm and 1.4mm wall thickness so this gives them an ID of either 19.0mm or 19.4mm so I will take my piece of 3/4 which is 19mm and see which fits best, and they sell it by the meter.
I'll let you know how which size I decide on.

Cheers

Marcus

Offline Hutch

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Re: TS Foot Board tubes
« Reply #14 on: 20 Apr 2022 at 03:03 »
The 1/4 rod is about 17" long (measured on an original) and the threads at each end are 17/64 25tpi.
That's interesting. Was the thread rolled on the 1/4 rod, like a giant spoke?

Leon

I don't think the thread was rolled Leon. I did a quick and rough set of measurements by winding some 0.020" wire around the threads of the LMDCC 17/64" 25 tpi tap, a 17/64" 25 tpi threaded bolt out of my junk box that appeared to have a good thread and the 1/4" footboard rod.

The wire diameter was such that it only just cleared the thread crests of the tap so was only just big enough. It cleared the crests of the bolt and rod thread reasonably well. The diameter of the crests of the wire was then measured;

LMDCC Tap 0.268" - 0.269"
Bolt            0.266"-0.269"
Rod            0.264"-0.267"

These measurements don't tell if the thread of the rod is rolled or cut with a die, but does appear to indicate that the thread pitch diameter is approximately the same for all three examples.

The crests of the rod thread are at 1/4" or just under and as I would expect a rolled thread to have the crests above that figure, I think Douglas (or whomever manufactured this part) just ran the 17/64" die down the rod and said "...near enough.."

This is the only footboard rod I have inspected close up so others could be different and maybe there is better evidence of a rolled thread. I think I would need something like an optical thread comparator to be able to definitively say that the thread was rolled or cut, but at this stage I am erring towards the latter.

Unfortunately the thread ends (on both ends of the rod) are corroded so I cannot use this to pick if the thread was cut or rolled (i.e. I assume the cut one would have a sharp root end and the rolled one would be rounded - but I may be wrong in this assumption)

Cheers

Hutch

Offline cardan

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Re: TS Foot Board tubes
« Reply #15 on: 21 Apr 2022 at 03:26 »
I'd imagine the 17/64-25 thread was just rolled onto the 1/4" rod - similar rolled threads are sometimes seen on  mudguard stays.

Leon

Offline Marcus

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Re: TS Foot Board tubes
« Reply #16 on: 22 Apr 2022 at 02:02 »
Hi Everyone,

Thank you very much for all the information. Here are the finished tubes and fittings ready to mount on the frame once I get it cleaned up.

Hutch,
I used 7/8 with 1.6mm wall thickness tube as it is a tight sliding fit, still possible to push it on by hand but is nice and tight even without the clamping rod but once that is fitted and tightened its absolutely solid.

Cheers

Marcus

« Last Edit: 22 Apr 2022 at 05:08 by Marcus »

 

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