BritBike Forum logo
BritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorThe Bonneville ShopBritBike Sponsor
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments.
Buy BritBike staff a coffee
Buy BritBike's staff a coffeeStill here since 1996 serving BritBike enthusiasts..
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Member Spotlight
Clanger
Clanger
Northants
Posts: 184
Joined: April 2006
Show All Member Profiles 
Newest Members
Tim Schumann, Superspin1, Spot, longstroke, Lovatomi
10899 Registered Users
Top Posters(30 Days)
franko 106
DavidP 70
quinten 67
Popular Topics(Views)
1,048,226 mail-order LSR
a word from..
Forum Statistics
Forums34
Topics68,016
Posts682,611
Members10,899
Most Online14,755
May 5th, 2019
Who's Online Now
52 registered members (6T), 379 guests, and 844 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
drilled drums #778401 07/11/19 7:26 pm
Joined: Jul 2019
Posts: 1
betty plava Offline OP
New poster
OP Offline
New poster
Joined: Jul 2019
Posts: 1
https://s1378.photobucket.com/user/...949s_zps8qnofkay.jpg.html?sort=3&o=1
https://s1378.photobucket.com/user/...950s_zpsquu4r43n.jpg.html?sort=3&o=0
"nothing lighter than a hole" apparently, so bought a 1 1/2" HSS carbide tipped hole cutter especially for the job. but on centre punching the first indent (of 6) on the inside of the SLS drum on my BSA A65, a cap just popped out - so i guess the easy provision for some extra fresh air was already built in??? weighing the 6 caps = 10.4 grams so not much of a diet there.
added some budgie mesh to keep critters out.
on to the rear
https://s1378.photobucket.com/user/...944s_zpsgm7u2kh1.jpg.html?sort=3&o=8
https://s1378.photobucket.com/user/...938s_zpskum4njdp.jpg.html?sort=3&o=9
the area available on the rear is smaller so i was planing on smaller holes. no indents on the rear so i made a template with 6 holes marked equidistant between the spline bolts. again, bought a brand new drill, fully expecting to burn it out on the cast iron. centre punched, then starting with a 4mm drill as a guide hole, i was surprised to have it bore straight through with little effort. jumping to the next size(s) up i noticed the metal wasn't producing the expected pasta curls of swarf but odd chips. the depth of the hole/thickness of the vertical face of the drum is only 5mm (the front is 7mm) but i expected a tougher material. it almost feels/looks like bakelite with a few iron filings thrown it just to make it metallic.

so finally my question: what is the rear drum of a 1966 BSA A65 made of?
i'm not confident to drill the now 14mm holes any bigger for fear of weakening the structure.

Support Your #1 BritBike Forum!

Check out British motorcycles for sale:
British Motorcycles on e-Bay UK
British motorcycles on e-Bay North America
Re: drilled drums [Re: betty plava] #778416 07/11/19 9:46 pm
Joined: Dec 2004
Posts: 10,116
kommando Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Dec 2004
Posts: 10,116
Could be cast steel, Norton Commandos rear brake hubs are cast steel. You can use a grind test on a piece to tell you if it's iron or steel.

https://en.m.wikipedia.org/wiki/Spark_testing


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | DVD- Manuals & Parts books
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.7.3