1956 Model 19S thread sizesUp to Singles
1956 Model 19S thread sizesPosted by mark_bishop at February 24. 2012
hi im rebiulding a model 19s and could do with some help on some nut and bolt sizes. the first one is the rear engine mount to frame bolt 4 of them i need to know what size they are. also the top gearbox bolt with the adjuster on i need to know the size of the nut. and where can i get these new would be a great help. thanks
Re: 1956 Model 19S thread sizesPosted by eugene_brolund at February 24. 2012
Hi Mark, I am not sure what country you are from, but I recommend Molnar if you want stainless: http://www.manx.co.uk/pdf/MPL-Norton_Singles.pdf
If you want stock finish, you might try Norvil (if you dont see it , email a request for a quote): http://www.manx.co.uk/pdf/MPL-Norton_Singles.pdf
or Domi racer : www.domiracer.com/homepage.html
Re: 1956 Model 19S thread sizesPosted by mark_bishop at February 25. 2012
HI skip, im from cornwall in uk thanks for you help.
Re: 1956 Model 19S thread sizesPosted by albert_sheean at February 26. 2012
I've gotten some engine mounting bolts and nuts from Russell Motors for my 1958 19S, they advertise in the two main "Classic" motorcycle publications.
Re: 1956 Model 19S thread sizesPosted by mark_bishop at February 26. 2012
hi albert thanks for the info.
Re: 1956 Model 19S thread sizesPosted by albert_sheean at February 29. 2012
You're welcome, use the Norton parts numbers and they'll send the exact item you need. Provided they have it in stock.
Re: 1956 Model 19S thread sizesPosted by Chris Grimmett at February 29. 2012
The Technical section of this web site has a Screw thread identification chart - it probably doesn't cover the big gearbox adjuster though. Cycle thread (BSCY) is not shown on the chart as they are all 26 t.p.i. Except, they are not.
7/16" BSCY can be found in standard 26 t.p.i. format and also in a 20 t.p.i. version. Just to add to the fun, 7/16" UNF is also 20 t.p.i. I found that I was having trouble with the rear engine plate mounting bolts and it was all down to this. Unfortunately, I can't remember which of the two it was in the end. Although the t.p.i. is the same on both, the threadform will be slightly different and fittings will snag up if you use the wrong one. In stainless, it will of course be worse.
Re: 1956 Model 19S thread sizesPosted by albert_sheean at March 01. 2012
If my fading memory serves, the threads on the front engine mounting bolts was indeed 7/16-20 t.p.i. I cannot say what the threads on the bolts and nuts in question would be, without unscrewing the actual bolts and measuring them.
I'm not real crazy about stainless steel fasteners. In my non-motorcycle related experience with stainless, threads would gall and the fastener ended up snapping off. If the bike is never to be dismantled again it is probably just fine, if the bike is to be worked on occasionally, use a different material. OR just a nut of a different material.
If one has to have stainless fasteners use aircraft grade items, they seem to be more resistant to galling.
Re: 1956 Model 19S thread sizesPosted by eugene_brolund at March 02. 2012
I have been using stainess steel fastners for some time in the house remodeling world & you are correct about the galling. If a thread is coated with Copaslip, or one of the other anti-galling compounds, no worries! But to state the obvious for the beginners, do not use any compound on the threads if you are using loctite! Use the correct loctite cleaner/de-greaser spray, then the correct type of loctite.
Here is some info on copaslip:
Copaslip is a High and low temperature assembly compound protects against seizure, fusion and corrosion in extreme conditions. Reduces wear and torque in areas of high friction. Prevents galling and pitting. Use to ensure easy dismantling and re-assembly of metal fittings. Can be used on all joints including nuts, bolts, battery terminals and spark plug threads. Copaslip offers protection from sub-zero temperatures to over 1100C.
I have also had good luck with "Molykote"
here is a good article on the subject: http://www.fastenal.com/content/feds/pdf/Article%20-%20Galling.pdf
Re: 1956 Model 19S thread sizesPosted by albert_sheean at March 02. 2012
when I relaced the wheels with stainless spokes and nipples on my BSA Gold Star, I was given a small bottle of green stuff by Buchanan's, the big big source for wheel components here in the U.S. I was told it was to prevent thread galling, it may have been the Copaslip you mentioned.
I used surplus aircraft fasteners extensively on my BSA as I was "personalizing" it, I figured there are enough restored goldies out there.
My model 19s is pretty much all original (sort of) I've elected to steer clear of shiny bits unless necessary. (new exhaust system)
Most commercial stainless fasteners seem to be made from 300 series for greater corrosion resistance, I think the aircraft stuff is likely made from 400 series for greater strength.
Sorry for straying from the original intent of this posting.