Author Topic: A65 stainless steel nuts & bolts  (Read 369 times)

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Charles R

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A65 stainless steel nuts & bolts
« on: 14 June, 2018, 18:01:50 »
I'm trying to replace as many of the bolts, studs etc as possible with stainless steel equivalents on my 1970 A65L.
There are at least a couple of issues with this.

1. Will the stainless steel equivalent be strong enough?
2. What are the sizes/threads?

For most, the latter question is simply answered by checking the old bolt.  However in my case the old bolt is sometimes missing and other times is blatantly not the correct part.  For example the bolts that should be holding the fork caps have been replaced by over-long studs, but at least I know they are 5/16" UNF.  Others are less obvious, for example the fork drain plug, is it 2BA or what?

Does a list exist identifying all these types of fixtures such that I could then buy a stainless steel version?  Do any of the fixtures need to be made in high tensile steel?

Cheers, Charles
My bike: 1970 A65L (pre OIF) - Basket Case with many issues

A10 JWO

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Re: A65 stainless steel nuts & bolts
« Reply #1 on: 14 June, 2018, 18:13:03 »
Pinch bolts H/T. I got 90% of my sizes from Draganfly's parts list. Find a main supplier of S/S, a few lads on here posted a few recently on one of the threads, try searching S/Steel. Regards.

JulianS

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Re: A65 stainless steel nuts & bolts
« Reply #2 on: 14 June, 2018, 18:52:04 »
The parts book shows the thread sizes of a number of the fixings. It also shows the material specification of some of the fixings - those needing high tensile fittings.

The 1970 bikes had a mid season change from bolts to studs and nuts for the fork end caps. The service bulletin below shows the change.

Bess

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Re: A65 stainless steel nuts & bolts
« Reply #3 on: 14 June, 2018, 20:56:21 »
Hi Charles,
                 Try this link for your 1970 A65 fixings part numbers:

https://www.draganfly.co.uk/index.php/a65anda50/category/126-1970-

Draganfly do a lot of stainless reasonably priced, if you want to make or source your own use this link for sizes etc.:

http://stainlessbits.com/link12.html

Best wishes...

Charles R

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Re: A65 stainless steel nuts & bolts
« Reply #4 on: 21 June, 2018, 10:18:34 »
Thank you all for your replies.

I live not far from Draganfly and went to see them yesterday.  I bought some parts (not related to my stainless steel query) from them and then asked them for advice on stainless steel.  They didn't seem to have any strong views and they do not hold much of a stock of bolts etc in stainless steel.

Specifically regarding the bolts (or studs) that hold the fork caps onto the fork outer member to clamp the wheel spindle, they supply ordinary steel bolts and not high tensile steel.  Their opinion was that SS bolts would be satisfactory.

As an aside, I've noticed in another post comments about the effectiveness of spring washers being questioned.  I think they may have missed the point that a spring washer is designed to dig into the the materials on either side of it when the head of the bolt rotates anticlockwise to prevent it from becoming undone.  The BSA parts list shows use of the spring washer under the head of a bolt.

I've included a photo of the two fork outer members, with one outer member having the end cap held by studs (as found on the bike), the other showing my intended solution with SS bolts & SS spring washers.

The photo shows how different the two outer members are.  Draganfly couldn't offer an explanation.  I'm assuming that the wheel spindle will bring the fork members into alignment and that 5mm discrepancy in the positions of the oil seal holders, either side of the wheel, will not be noticeable.  I'm also assuming the subtle difference in spring compressions will have no noticeable effect.

Thanks again for your help.

Cheers, Charles
« Last Edit: 21 June, 2018, 11:12:48 by Charles R »
My bike: 1970 A65L (pre OIF) - Basket Case with many issues

Bess

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Re: A65 stainless steel nuts & bolts
« Reply #5 on: 21 June, 2018, 11:13:26 »
Hi,
     That's strange about Draganfly, I just bought 12 fixings etc for my A10 in stainless steel an order totaling 84.

I was involved in discussions regarding spring washers.  Previously I found an interesting report commissioned by NASA, on nut locking it states that spring washers, "they serve as a spring while the bolt is being tightened. However, the washer is normally flat by the time the bolt is fully torqued. At this time it is equivalent to a solid flat washer, and its locking ability is non existent. In summary, a lock washer of this type is useless for locking".

The issue with the spindle was BSA's effort to overcome the forks binding. They drilled the spindle holes at 89 degrees not 90. There are lots of issues and problems with this and most people source fork tubes and caps at 90 degrees or machine the spindle hole back to 90 degrees.

Best wishes...
« Last Edit: 21 June, 2018, 11:19:55 by Bess »

Charles R

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Re: A65 stainless steel nuts & bolts
« Reply #6 on: 21 June, 2018, 11:36:02 »
Thanks Bess

I may not have asked the question re SS fixings correctly!  Draganfly didn't seem to be eager to provide a simple way of getting hold of the SS fixings.

Regarding the spring washers, I suppose it depends how much demand is being made on the fixing.  I can understand why NASA may have had reservations because they have little opportunity to keep an eye on fixings and put them right in operation.  Is an alternative to use a flat washer and use stud-lock on the threads?

I'm not familiar with the fork binding issue and I don't understand why 89 rather than 90 would solve anything.  The problem with my forks, I believe, is that the outer members are of different lengths because they are of different build standards (different models, years?).  In addition the end caps are different, which to the casual observer makes the two assemblies look the same size until you put them close together (as in the photo) and then you can notice that the wheel spindle location is 5mm out of alignment.

I've been given the impression from various people and articles/books that when my bike was produced (1970) BSA were in trouble and were using whatever stock was to hand.

I'm just hoping that the 5mm difference is not an issue for bike handling.

Cheers, Charles
My bike: 1970 A65L (pre OIF) - Basket Case with many issues

Bess

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Re: A65 stainless steel nuts & bolts
« Reply #7 on: 21 June, 2018, 12:03:54 »
Hi Charles,
                NASA do provide scenarios for different fixings and locations. I am using a mixture depending on the temperature around the application, report here:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900009424.pdf

Just realised you were involved in this thread:

https://www.bsaownersclub.co.uk/bsaoc_forum/index.php?topic=1817.0

Let me know your resolution, I fitted sliders with the hole drilled at 90 degrees.

Best wishes...
« Last Edit: 21 June, 2018, 12:19:28 by Bess »

Charles R

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Re: A65 stainless steel nuts & bolts
« Reply #8 on: 21 June, 2018, 13:32:51 »
Hi Bess

Serious reading from NASA!  Reviewing what they've said on the subject, I've decided that the SS bolt with a plain SS washer and loctite on the threads looks like the best option for taming the fixing.

On the subject of 89/90, I've clamped my two fork members together so that the bodies are exactly parallel to each other and the wheel spindle ends are coincident (see photo).  I've then placed a steel rule against the wheel spindle "grooves" to check any angle difference.  I can't see anything other than they are also parallel, ie at 90 to the fork member body.  It's difficult to photograph but I've included some close-up shots.  I haven't a wheel spindle at present, otherwise I would clamp it on and see how non-parallel the member bodies would be.  I'll have to do that at some later stage.

Cheers, Charles
My bike: 1970 A65L (pre OIF) - Basket Case with many issues

Bess

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Re: A65 stainless steel nuts & bolts
« Reply #9 on: 21 June, 2018, 16:19:31 »
Hi Charles,
                It could be someone has machined the spindle slot square to the sliders, making the wheel upright in use. The only issue will be the sliders are still different lengths (not sure how that will affect the springs, probably not much) and your mudguard stay brackets wont be parallel.

Best wishes...
« Last Edit: 21 June, 2018, 16:27:03 by Bess »

Charles R

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Re: A65 stainless steel nuts & bolts
« Reply #10 on: 21 June, 2018, 22:07:26 »
Hi Bess

I don't get the impression that the spindle groove has been re-machined, but who knows!

Good point about the mudguard.  I'll just have to find a workaround when I come to that part of the rebuild.

Cheers, Charles
My bike: 1970 A65L (pre OIF) - Basket Case with many issues