Thanks Ron, Yes I have done that, And it looks good enough for me, Cheers , Bill.
Tank mounting misalignment
- Thread starter Oldhaven
- Start date
Thanks David but....
Wow, that's kind of worrisome. With the UFM on its right side and the 1/2 rod through the front mount in my mill collet I get a difference of .5 plus or minus .01 and the side of the tank is almost perfectly aligned with the table. In other words, the right outer surface of the front head mount sits on a 1" block so the inner surface is at 1.25 from the table. (This section is only 1/4 thick!!, seems pretty marginal but I guess it works). I measure the inner surface of the rear mount at almost exactly .75 and a 3/8 spacer block just fits underneath its 3/8 thickness. I have to push pretty hard against the front mount rod to get the extra 1/8 inch for 5/8, though it does get there, and I have had it on the engine head brackets before without much trouble. That is the least of my worries, I just need the correct figure for my bending setup. Back to measuring.
Ron
Wow, that's kind of worrisome. With the UFM on its right side and the 1/2 rod through the front mount in my mill collet I get a difference of .5 plus or minus .01 and the side of the tank is almost perfectly aligned with the table. In other words, the right outer surface of the front head mount sits on a 1" block so the inner surface is at 1.25 from the table. (This section is only 1/4 thick!!, seems pretty marginal but I guess it works). I measure the inner surface of the rear mount at almost exactly .75 and a 3/8 spacer block just fits underneath its 3/8 thickness. I have to push pretty hard against the front mount rod to get the extra 1/8 inch for 5/8, though it does get there, and I have had it on the engine head brackets before without much trouble. That is the least of my worries, I just need the correct figure for my bending setup. Back to measuring.
Ron
I have a lot of respect for David, So I tried to MAKE it 5/8 ", Can't do it, Putting a straight edge inside the fork I can only get 1/2", Come On Clev Trev, You must know it, Cheers Bill.
Hi Bill,
As a quick check, hopefully to put your mind at rest, fit long bars through front and rear sidecar mounts. M16 studding with nuts to square it up against the tube faces should do. If you roughly centralise both studs you should be able to measure the distance between them at each end. You could just use a steel tape or you could makeup a crude fixed guage by putting a couple of nails in a bit of wood or just cut a bit of wood to fit betweenthe two studs. This should let you compare one side with the other.
Good luck,
As a quick check, hopefully to put your mind at rest, fit long bars through front and rear sidecar mounts. M16 studding with nuts to square it up against the tube faces should do. If you roughly centralise both studs you should be able to measure the distance between them at each end. You could just use a steel tape or you could makeup a crude fixed guage by putting a couple of nails in a bit of wood or just cut a bit of wood to fit betweenthe two studs. This should let you compare one side with the other.
Good luck,
Bill,
I may have let you down. Someone is checking for me, but it looks like it is .5". I have it on a jig, but I cannot easily measure the jig because some other brackets are in the way. When I measure the UFM I am getting closer to .5".
Thanks Ian, Good idea, I am happy with mine, I have seen some funny dents in oil tanks, But bending a head stock, Is strange to me !, I wonder what happened to Ron's, I have straightened a very bad rear frame, And the Saga with Kevin's fork blades, Just shows we have to be careful, Glad I did not pay much for my bikes !! A dealer told me the other day, A "D" went for £91,000 in bits !!. Cheers David , I thought I had a good eye, Well one of them anyway ! but it is not easy, To be honest, One side was a little less than .5, But I think it will be OK, I seem to remember I have to Nudge the rear fixing of my D Special a bit !!, Like us these bikes are getting Old !. Have Fun, Bill.
NOBODY expects the Spanish Inquisition!
Well, I have come to a (mostly) satisfactory conclusion to the bent UFM. the stone axe engineering seems to have helped. (picture 372 is a picture of the setup.) I had the high lift with a 4 foot extension on the handle and a piece of A2 steel machined to fit the steering column and bearing pockets. I gave it all I felt comfortable with, (considerable, I can't believe how strong this thing is) and left it overnight. I know at that point I could feel it at the deformation under load point. That was where I stopped.
Next day I t did a post torture set up of the complete UFM
using the head brackets flat on the mill and the fitted mandrel through the
headstock. (That 1 1/2 inch A2 did not bend a bit) Using a dial indicator I checked the angularity of the
steering axis. I found that it leaned to the right about .060" in 4".
This would mean, If I am thinking correctly, that I would be approximately
3/8" to the right of the correct position at the tire patch about two feet
from there. Not too bad, but not perfect. This is picture 373.
I then removed the headstock and put it on its right hand side as David D
suggested earlier. (and I really want to thank him and all who chimed in with suggestions and encouragement). With all the tank mount machined surfaces on spacers I
found that the steering axis was off to the left by .004 in 4 inches.
This means that my bending had some effect and I even over corrected a
bit, but using the same math, I would be off only .024 at 2 feet if the
steering axis and tank mount surfaces were all I had to worry about. This
is picture 376
So where is the bend to the right coming from? I assume some of it is in
the tank itself, which is stronger and harder to correct than it looks, and there is a slight
wrinkle in the sheet metal on the right side, indicating a permanent
deformation that would be hard to fix. I think I got a lot of that
with the high lift, but not all. The next thing I looked at was the head
fork. There is some bend there after all. Relative to the tank mount
surfaces, both the 1/2 holes in the fork for the head bracket and the two
tank mount holes next to it show difference of about .095 in 6 inches.
This means that the tubular part that connects them to the steering column
is still bent, or rather that the fork is rotated relative to the steering
column. Since the head bracket is a big piece of metal connected to a
stiff engine, the effect is to put the steering axis to the right. The real lesson I learned is that the UFM must be considered as a unit, and correcting just one part will not t fix everything and may even make things worse. This is picture 377
It then occurred to me that rather than trying to correct the steering
column rotation, it would be easier to correct the fork. I put a 1/2 rod
in the top fork hole and placed it not through the bottom hole but just
under 1/16th inch in a direction to correct the rotation and presto, there
was no misalignment.
So, I think I will try a couple of things in increasing order of
difficulty, and if I am lucky, one will work satisfactorily.
For the fork rotation, I will just put it together and ride it, and see if
it causes handling problems. If it does, the next easiest thing is to put
thins shims on top of the head nuts on the left of the front head below the
head bracket. this will rotate the steering axis to the left slightly.
Even Phil Irving thought about this:
from MPH 378 "Excessive tightening and/or overheating is likely to cause
permanent deformation of the bolt bosses, and subsequently going round the
bolts and again over-tightening them eventually results in causing one or
more of the bolt bosses to co llapse. The one most likely to be affected
is at the near side of the front cylinder which apparently runs hottest,
but any of the others might suffer in a particularly bad example. Besides
being squeezed down below its original height, the boss may have cracked
away from the top fin, but the head may still be usable. This sort of
defect, though rare, is sometimes found on engines fitted to hill-climb
cars without the head brackets in place. It may well be that the absence
of these components allows the bolts and bosses to deflect outwards, thus
causing the cracking of the top fin. If such an engine is being put back
into a standard machine, it is essential for the tops of all the head nuts
to be parallel to the joint face which will necessitate packing up the low
nuts wit h thick washers or shims. This precaution may seem a little
finicky, but any slight inclination of the head bracket will throw the
steering column out of line by an equivalent amount" (My emphasis here).
Finally, if that is not satisfactory, I can fill and re-machine one of the
1/2 holes in the fork to move it that little bit necessary to correct the
steering axis. this would be a fix that would be useable for another
machine if the UFM ends up with its correct engine someday. I will not
worry about the two lower oil tank mount holes since these fit the tank as
they are and moving them would cause problems.
As a bonus, when I reassembled the headstock to the tank, the petrol tank now fits easily, even though I did not completely correct the rotation of the bosses. They improved enough that it is not a real problem, especially if they are done first, before the rear tank bolts. the outer race of the bottom taper bearing also fits better than it did before the torture, and is centered in the pocket with the correct interference fit fore and aft. Though some stretch exists at the sides, it is within the gap filling powers of the Loctite supplied with the Patzke kit.
Finally , I attached picture 380, since it shows an interesting thing
about the oil tank holes in the headstock of this late 1948 B
. The front 3 seem to have been drilled off the
cast bosses centers quite a bit, which would rotate the oil tank up at the
front a little bit. This might affect the angularity of the rear head
mount bracket slightly, though I suppose this was all done in a fixture.
I can't see any real problems, as I am not sure it would affect the trail,
but interesting.
So, all in all, a very informative exercise for me, and I can get back to other things awaiting attention, like the RFM and brakes.
Ron
Well, I have come to a (mostly) satisfactory conclusion to the bent UFM. the stone axe engineering seems to have helped. (picture 372 is a picture of the setup.) I had the high lift with a 4 foot extension on the handle and a piece of A2 steel machined to fit the steering column and bearing pockets. I gave it all I felt comfortable with, (considerable, I can't believe how strong this thing is) and left it overnight. I know at that point I could feel it at the deformation under load point. That was where I stopped.
Next day I t did a post torture set up of the complete UFM
using the head brackets flat on the mill and the fitted mandrel through the
headstock. (That 1 1/2 inch A2 did not bend a bit) Using a dial indicator I checked the angularity of the
steering axis. I found that it leaned to the right about .060" in 4".
This would mean, If I am thinking correctly, that I would be approximately
3/8" to the right of the correct position at the tire patch about two feet
from there. Not too bad, but not perfect. This is picture 373.
I then removed the headstock and put it on its right hand side as David D
suggested earlier. (and I really want to thank him and all who chimed in with suggestions and encouragement). With all the tank mount machined surfaces on spacers I
found that the steering axis was off to the left by .004 in 4 inches.
This means that my bending had some effect and I even over corrected a
bit, but using the same math, I would be off only .024 at 2 feet if the
steering axis and tank mount surfaces were all I had to worry about. This
is picture 376
So where is the bend to the right coming from? I assume some of it is in
the tank itself, which is stronger and harder to correct than it looks, and there is a slight
wrinkle in the sheet metal on the right side, indicating a permanent
deformation that would be hard to fix. I think I got a lot of that
with the high lift, but not all. The next thing I looked at was the head
fork. There is some bend there after all. Relative to the tank mount
surfaces, both the 1/2 holes in the fork for the head bracket and the two
tank mount holes next to it show difference of about .095 in 6 inches.
This means that the tubular part that connects them to the steering column
is still bent, or rather that the fork is rotated relative to the steering
column. Since the head bracket is a big piece of metal connected to a
stiff engine, the effect is to put the steering axis to the right. The real lesson I learned is that the UFM must be considered as a unit, and correcting just one part will not t fix everything and may even make things worse. This is picture 377
It then occurred to me that rather than trying to correct the steering
column rotation, it would be easier to correct the fork. I put a 1/2 rod
in the top fork hole and placed it not through the bottom hole but just
under 1/16th inch in a direction to correct the rotation and presto, there
was no misalignment.
So, I think I will try a couple of things in increasing order of
difficulty, and if I am lucky, one will work satisfactorily.
For the fork rotation, I will just put it together and ride it, and see if
it causes handling problems. If it does, the next easiest thing is to put
thins shims on top of the head nuts on the left of the front head below the
head bracket. this will rotate the steering axis to the left slightly.
Even Phil Irving thought about this:
from MPH 378 "Excessive tightening and/or overheating is likely to cause
permanent deformation of the bolt bosses, and subsequently going round the
bolts and again over-tightening them eventually results in causing one or
more of the bolt bosses to co llapse. The one most likely to be affected
is at the near side of the front cylinder which apparently runs hottest,
but any of the others might suffer in a particularly bad example. Besides
being squeezed down below its original height, the boss may have cracked
away from the top fin, but the head may still be usable. This sort of
defect, though rare, is sometimes found on engines fitted to hill-climb
cars without the head brackets in place. It may well be that the absence
of these components allows the bolts and bosses to deflect outwards, thus
causing the cracking of the top fin. If such an engine is being put back
into a standard machine, it is essential for the tops of all the head nuts
to be parallel to the joint face which will necessitate packing up the low
nuts wit h thick washers or shims. This precaution may seem a little
finicky, but any slight inclination of the head bracket will throw the
steering column out of line by an equivalent amount" (My emphasis here).
Finally, if that is not satisfactory, I can fill and re-machine one of the
1/2 holes in the fork to move it that little bit necessary to correct the
steering axis. this would be a fix that would be useable for another
machine if the UFM ends up with its correct engine someday. I will not
worry about the two lower oil tank mount holes since these fit the tank as
they are and moving them would cause problems.
As a bonus, when I reassembled the headstock to the tank, the petrol tank now fits easily, even though I did not completely correct the rotation of the bosses. They improved enough that it is not a real problem, especially if they are done first, before the rear tank bolts. the outer race of the bottom taper bearing also fits better than it did before the torture, and is centered in the pocket with the correct interference fit fore and aft. Though some stretch exists at the sides, it is within the gap filling powers of the Loctite supplied with the Patzke kit.
Finally , I attached picture 380, since it shows an interesting thing
about the oil tank holes in the headstock of this late 1948 B
cast bosses centers quite a bit, which would rotate the oil tank up at the
front a little bit. This might affect the angularity of the rear head
mount bracket slightly, though I suppose this was all done in a fixture.
I can't see any real problems, as I am not sure it would affect the trail,
but interesting.
So, all in all, a very informative exercise for me, and I can get back to other things awaiting attention, like the RFM and brakes.
Ron
Hello Ron, You have some good tooling there, If anybody can fix it , You can !. Did you see that youtube bit about a year ago, Where a newish bike was straightened, More or less, With out taking the bike apart !!, Must say, I did not like it, I thought new bikes were strong but they look like junk to me. Some of the Pot holes I have hit in UK this year, Would destroy them !! Good Luck, P.S. Are new head stocks for sale, I wonder if it would be better to buy a new one, There is a bloke in London making new rear frames, B and C, Selling them on Ebay, Cheers Bill.
Thanks Bill. I'm pretty limited in the shop because it is set up as an industrial engraving operation. Everything is pretty small, and as you can see, crowded. I wish I had the equipment and skill to do frame fabrication like some of our more talented members. I do have 2D and 3D Deckel and Gorton pantographs and while they are not CNC machines, they can do some interesting things with a good template.
I reckon if you hit anything hard enough it will bend, and what it takes to bend the Vincent UFM is pretty amazing. I can see that the later headstocks were probably stronger, but this type 1 only weighs 6 pounds.
VOC spares has new headstocks in stock right now, and complete UFM's and oil tanks, though they are out of stock. I do wish quantity would bring down the cost, but this is an exceedingly small market, especially when matching numbers and originality seem to matter so much .
Ron
I reckon if you hit anything hard enough it will bend, and what it takes to bend the Vincent UFM is pretty amazing. I can see that the later headstocks were probably stronger, but this type 1 only weighs 6 pounds.
VOC spares has new headstocks in stock right now, and complete UFM's and oil tanks, though they are out of stock. I do wish quantity would bring down the cost, but this is an exceedingly small market, especially when matching numbers and originality seem to matter so much .
Ron