FF: Forks Modified Steering Stem

[davidd]

I am always amused when Randy, my flywheel builder, measures the bore of the big end of the Carrillo rod taken out of the flywheels and bounces the big end on an anvil to make it round again. I know he is doing it because he can. It will not stay round very long, but it is the best you can do.

I think those who are riding around with Greg's conversions are really enjoying themselves and I would guess that there would have been little Greg could have done to those parts to improve the rider experience even more.

I am not using exactly the same bearings, but when I set up the links everything fits quite nicely. On the racer I used one of the new lower links and I assume the play in the bearings allows them to work merrily while keeping everything as straight as possible. Everything has worked quite well without extensive measurement. The FF1's are done on the mill and the top link is reamed with a piloted reamer.

I think plan B is very sensible and will serve these wonderful old heaps really well.

David

 

[greg brillus]

I mean obviously if the link is bent quite a bit, and I mean if you put a straight edge along the sides of each eye and check the gap verses the front bush on either side and they are quite different, then you need to do something, just the same as per Norman's findings about the horizontal plane of the pair of eyes verses the centerline of the FF6 bushes, if this is out by miles, then you should try and straighten as best you can. Some might find it crude and a bit like David's example above, but I simply hang onto the link in a pair of soft jaws in a descent vice, heat up the offending arm and bend it usually with a big Adjustable Crescent "Shifter" and it can take several goes before you can effect a descent outcome. But I have done several in this way, and the outcome is always far better than how it was before. A bit of preparation with a couple of good straight edges and a good copper faced hammer are useful at the time. Unfortunately it usually spells disaster for the paint job, so a light sand blast and re-paint is needed once all the crashing and bashing is finished.............

 

[vibrac]

A crescent wrench and a copper faced hammer sounds like the sort of tools well to the fore in the old high street at Stevenage they were called fitters not assembly line operatives back then.

 

[Steve G]

...it did not fall apart even with all the bending and tweaking I did to it. I would not worry to much............they are a very strong component.

Thanks Greg. My question was asked with a wink and a smile. You did a first class job on reconditioning the link. A vast improvement over what I sent you.

 

[greg brillus]

Slightly off topic, but anyway............Years ago when I was doing my apprenticeship I used to do volunteer work at a local museum on weekends helping a couple of old blokes who were restoring some vintage cars. There were lots of old memorabilia around the walls including many old tools, oil cans and the like. Up on one of the walls, I was looking at a very early version of a "Socket set" made many years ago. One of the old chaps who was extremely knowledgeable on the vintage cars told me that years ago the "Then" inventor of this socket set had gone to several Tool manufacturers at that time looking to see if one might be interested in his "New design" at some point he approached "The Crescent tool co" who upon inspecting his new idea told him that this would never take off and he was basically wasting his time. How wrong could they have been......And for many, many years "Crescent" never made any socket sets.......... Perhaps too embarrassed by their lack of foresight all those years ago. We generally think of a "Crescent" as an adjustable spanner/wrench to which I'm sure they've sold many thousands of these useful tools ..............Imagine if they'd got the patent on "Socket sets"

 

[Dave61]

Right; this is going to take a while so please stay with me. I got a phone call from the chaps who have the line boring equipment this afternoon. Although they told me they could not do the job for three weeks they had nevertheless got on and done some measuring and it is not good news. I had given them seven lower links to be machined, one of which is brand new and belongs to Stu Spalding. It is unpainted and clearly never been fitted to anything. They had set up several of the links with a spindle through the two front Oilite bushes. This is an as new original Vincent spindle supplied from my bike. The spindle was placed in vee blocks on a surface plate and the rear two eyes allowed to rest on the surface plate. They then clocked the inside of the rear eyes off the surface plate. At first I thought that the potentially different thicknesses of the forged eyes could cause a problem but I soon realised that by measuring the inside of these eyes the thickness of the outer material makes no difference. You might have to think about this for a while, I certainly did. With the old lower links the differences in height were all over the place but generally tens to several tens of thous. I then got them to do the same with the brand new one. There is 22 thou difference between one side and the other. Twenty two thou gentlemen. To take the eyes from 1.25 inches to two thou under 32 mm one needs to take a cut of four thou, that is eight thou off the diameter. To imagine where this misalignment is please imagine taking hold of a lower link by the two rear eyes so that the front is away from your body. Then imagine pushing down on one side and up on the other. That is the amount of twist in that direction. We then set up the new lower link in such a way that the distance from the front axis to the inner rear of the eyes was measured. On the new link the holes were parallel with the front spindle. We did not do the same with the older links. And there gentlemen we have the problem. The two previous people who claimed they could machine these eyes and then told me that they couldn't never explained why. The new chaps have been kind enough to not only explain but also to allow me to play with their surface plates, vee blocks etc and to see exactly what and where the problem is.

So we are now at a stage where we have to make a joint decision. It is not just old lower links which have distorted with time but even a brand new one is so out of line, twenty two thou, that it is impossible to machine four thou out and make the eyes in line. There is absolutely no problem machining each side separately so that the eyes are the correct size to take the ball races and are exactly in line with the front spindle. However, they cannot be made so that the two eyes are essentially at the same height. It would be possible to bend the lower links to that they are more in line but the chances of that bending staying constant in the future is considered to be just about zero by the machinists and it is not a route they would wish to go down. The only positive thing to be got out of this is that all these links, apart from the new one, have been in use for many years without the riders feeling any problems. I can see only two choices here and that is why this is so long because it affects all of those of you who are going to go for the bearing mod, or even continue to use Oilite bushes. The first would be to make new links, heat treat them to remove any residual stresses and then give them to someone who would be competent to machine them accurately. This might mean two machining operation. One a course cut to relieve some of the original stresses, de-stressing again and then a final cutting to size. This would be prohibitively expensive for most of us as new ones already cost about £400 and they, or at least this one sample, are not accurate. The second option is to accept that we have less than perfect machines and to just open up the eyes independently and just accept the fact that there will be some errors which are probably not detectable to the rider. For my self and my own lower links I will go for the second option. Please let me know either via this Forum or by PM what you wish to do.

Hello Norman,
I agree with you and would go for the second option,not that I have an engineering back ground, but as you say they have coped with their deficiencies up until now. PS. I`m Dave from the Isle of Sheppey.

 

[timetraveller]

Thanks for that Dave. I have been down to the machinists this morning and told them to do the best they can by machining each side up independently. The will clock up/centralise each side in a jig they have to make and which will ensure that the bored holes are exactly parallel with the front bore. They will then bore out each eye independently. They should be ready in about two weeks. It will be more work than trueing up once and line boring but that is the best that we can do.
Cheers.

 

[Dave61]

Thanks for that Dave. I have been down to the machinists this morning and told them to do the best they can by machining each side up independently. The will clock up/centralise each side in a jig they have to make and which will ensure that the bored holes are exactly parallel with the front bore. They will then bore out each eye independently. They should be ready in about two weeks. It will be more work than trueing up once and line boring but that is the best that we can do.
Cheers.

Really appreciate all the effort you are going to Norman.
I`m on a steep learning curve being used to working on modern ish bikes, my Vinnie is a "Ted Davis Special" basket case that I just want to get back on the road & be able to enjoy riding it knowing it can cope with my Wife & myself in relative safety.
It`s the first bike I`ve worked on where I can`t take for granted something will fit with ease.

 

[timetraveller]

Ok chaps, sorry for the delays but I am now sending out the last few of the orders for the last batch of 30. It is already clear that there will have to be another batch of at least ten so I will be asking people to declare an interest in the next few days/weeks. In the short term, and to ensure all those who have waited so patiently for so long get theirs first I have to ask some questions. First, will the chap who wanted a special steering stem made to fit the VOC Spares Company taper roller conversion contact me again. I have your special here but cannot find the original correspondence so do not know who you are. Secondly there are several people who I have emailed recently to let them know that the parts are ready who have not replied. If you are waiting and have not looked at your emails for some time now is the time to let me know. If you have changed your mind due to the long delay then that is not a problem as there are enough people waiting but it would be good to know so that I can sell on the parts already made.
If anyone is likely to be able to get a message through to Stu Spalding then would you please get him to contact me or send me a message via an intermediary. I know about his accident and that he is in a nursing home and I have emailed him, via the Forum, to let him know that there is absolutely no pressure to take his parts or to pay any money at present but it would be good to know how he feels about doing the modification in the future. It is probably worth saying that I have now had seven of the lower links opened up and have assembled three of them, including Stu's 22 thou out of line one. The good news is that when assembled there is no trace of stiffness or unwillingness to swing totally freely. In fact taking one of these to the local Vincent section club night a few weeks ago so impressed one of those present that he ordered one of the next batch immediately.
Incidentally it was Stu's brand new steering head which was out of line and separate private correspondence has shown that it was obtained from the VOSSC relatively recently. 22 thou out of line chaps!!
Finally, I have expressions of interest for at least three modified steering heads to be made in aluminium alloy. If these are made at the same time as the steel ones then there is likely to be very little difference in price. If you are interested in these then please let me know.

 

[Dave61]

Ok chaps, sorry for the delays but I am now sending out the last few of the orders for the last batch of 30. It is already clear that there will have to be another batch of at least ten so I will be asking people to declare an interest in the next few days/weeks. In the short term, and to ensure all those who have waited so patiently for so long get theirs first I have to ask some questions. First, will the chap who wanted a special steering stem made to fit the VOC Spares Company taper roller conversion contact me again. I have your special here but cannot find the original correspondence so do not know who you are. Secondly there are several people who I have emailed recently to let them know that the parts are ready who have not replied. If you are waiting and have not looked at your emails for some time now is the time to let me know. If you have changed your mind due to the long delay then that is not a problem as there are enough people waiting but it would be good to know so that I can sell on the parts already made.
If anyone is likely to be able to get a message through to Stu Spalding then would you please get him to contact me or send me a message via an intermediary. I know about his accident and that he is in a nursing home and I have emailed him, via the Forum, to let him know that there is absolutely no pressure to take his parts or to pay any money at present but it would be good to know how he feels about doing the modification in the future. It is probably worth saying that I have now had seven of the lower links opened up and have assembled three of them, including Stu's 22 thou out of line one. The good news is that when assembled there is no trace of stiffness or unwillingness to swing totally freely. In fact taking one of these to the local Vincent section club night a few weeks ago so impressed one of those present that he ordered one of the next batch immediately.
Incidentally it was Stu's brand new steering head which was out of line and separate private correspondence has shown that it was obtained from the VOSSC relatively recently. 22 thou out of line chaps!!
Finally, I have expressions of interest for at least three modified steering heads to be made in aluminium alloy. If these are made at the same time as the steel ones then there is likely to be very little difference in price. If you are interested in these then please let me know.

Hi Norman,
It was probably me that wanted the steering stem to suit the taper rollers but it was Christian Patzke`s ones.
I`ve sent you an email as well.
Cheers
Dave.