Restoring the last of the series "A" Comets.

[greg brillus]

Earlier up on this same page shows some of the clutch/brake lever assemblies showing the square head screws holding the clips to the perch. Can someone give a good picture and/or dimensions of these screws, It looks like the hex is about a 2 BA spanner size, and I'm assuming the threads are 1 BA. I will probably get a small batch made if anyone wants/needs them. Unless someone knows of some available somewhere........... Cheers............. Greg.

 

[Dinny]

Simon, chip in here with the sizes. I will be up for two sets of Greg what’s to have them made.

Cheers
Mark

 

[greg brillus]

Once I get a drawing or similar with some details I will see my machinist about making a small batch and will let you know. It would be good also to know what the original finish on them was, either cad or chrome plating I guess. And was it only the two main levers that had them..........Clutch and brake, what about the other lever attachment screws.......... ?

 

[Simon Dinsdale]

I made the strange handlebar lever screws for my A and they were right swines to make. I didn't have an original to copy at the time so did a bit of guessing looking at photos of others. The square head I made to fit a 2BA spanner and the thread was 7/32 BSF. This is virtually identical to 1BA and I tried both size of screws in my lever brackets and 7/32 BSF fitted the best so that's what I went with. You need to look at the threads in the levers you are using. You don't want to use the wrong thread and find it strips out of the lever bracket when you pull the brake on hard.
These strange square head screws were only used on the clutch and brake lever. The other levers just used cheese headed screws which have a very slight dome head. I think they are called slotted fillister screws and Amal used them a lot.

Don't forget these screws were probably made by Amal and not peculiar to Vincent's and most probably not always what Amal provided as they would have been expensive compares to a std slotted screw..
Like a lot of things Vincent would just use what they received from Amal or Miller etc. Its the same reason on series B's bikes were fitted with 6.5" headlights and 8" headlights at the same time. Vincent just ordered a Miller lighting set and fitted whatever Miller provided on that day.

Greg is correct that the decompressor was the short type that has a gently S bend to the lever.

Simon

 

[greg brillus]

Thanks Simon, I will see what I can come up with. My machinist is always up for a challenge.

 

[A_HRD]

Greg,

Sorry, but I have an alternative view! A few years ago I made up 2 pairs from an alleged rusty original as follows:
Starting from the square end and working along the bolt:
Rounded end - likely 5/16 rad. 5/16 A/F square (so is Brampton spindle) and 5/16 long,
Then tapers into a waisted radius, 1/4 dia at min point, 3/32" long.
Then a 5/16 dia parallel shoulder, 1/8th long.
Then the "stud" part:- 1/4 dia, 5/8ths long, with 1/2 inch of 1/4 BSF thread.

Like Simon says, go with the thread in your lever brackets!

I haven't got the time at the moment, but I'll see if I can draw-up a dimensioned sketch and post it in the next 24 hours...

Peter B

 

[Bill Thomas]

That's funny Peter, I have just found one, And picked up a 5/16" spanner, And thought the same.
As you know, I am + or - an inch !!.
Cheers Bill.

 

[vibrac]

Some of the confusion is because Amal is 1BA and Docherty and others were 1/4X26 whenever I have to do the job now I use 1/4 cap screws I found I could get the torque out of those to keep the scrutineers at bay and the habit has continued if I have a problem

 

[greg brillus]

They sound very similar to the carb clip clamp screw, except with a square and not a hex.

 

[A_HRD]

Here is the dimensioned sketch that I promised (one dark and one light - whichever works best for you):

Peter B