Machining Drums and Discs - any advice

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A standard tool room lathe won't be rigid enough for this task.
A trick to get round this is a special toolpost that has 2 cutters, one for each side of the disc, the cutting forces being opposite cancel each other out, downside is making the toolpost and the overhang to do a full width cut on old design discs.
 

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I had considered grinding my front rotor with a fixture.
It was easier to do a couple of 140 km round trips (on the Africa Twin DCT) to drop it off and pick it up 3 months later @ AU$128 Blanchard ground.
A new rotor of debatable quality (run out) was $330.

Chatter is normally tooling (including profile and depth of cut) or lack of rigidity or in combination with a harmonic.

I bodge my way through a few jobs on machine tools but there are times when it is easier to drop things off on occasion (or wait by the mailbox)
#
I did buy a DID X ring 530 chain but elected to not use it as it was to close to the gearbox (Mk2a) for my liking as is, I replaced the original drive chain with an endless non O-ring IWIS M106SL instead.
 
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Are you certain that the sprocket needs to be cut down?
Modern x ring 530 is quite a bit narrower than ten year old o ring 530.
I slid an xring 530 on the MK3.
Also on the 650ss and the Vincent.
In order to go to sealed chain, all those bikes would have gotten a 520 " conversion a few years ago.
The sealed chain is the way to go.
You won't be able to make 630 sprockets into 530 or 525.

Glen
Chain width, I'm thinking that 20mm is about the max to avoid potential issues.
Will have no issues on the Atlas.
Sealed chain I am sure is the way to go even though chains such as the IWIS look to be a good spec.
Z1 chain: As soon as I sent the post remembered the 3/4 pitch, duh! Just ordered a 5/8 gearbox and rear sprocket kit.

A standard tool room lathe won't be rigid enough for this task. If you have access to a vertical mill it's possible to surface the discs with a face mill (though I personally wouldn't trust it unless I was absolutely certain that the machine was within 0-.0005tir). The rear drum, however, should be easy enough to machine with this setup and a decent rotary table
Have ruled out the milling machine option. Set up on the 8inch table and a marginal face mill makes for more effort than I want.

Was going to the chromer on Monday, so will drop off some discs as well.

Just received last week one RGM UK made 520 drum - Very nice, just an expensive way to go for a few units. But after chrome removal will try on my brake lathe.
 
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The casting is very thick by the sprocket. Even if the chain takes a tiny bit out there in its first few times around, no harm. Both of my Nortons ran clear right off with the 530 vx.
There is also a special version of the 530x ring that is made for classic bikes with tight clearances. It is narrower than the DID vx 530.
I'll have to dig around to find the info

Glen
 
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Interesting comment from Glen:
"Are you certain that the sprocket needs to be cut down?
Modern x ring 530 is quite a bit narrower than ten year old o ring 530.
I slid an xring 530 on the MK3.
Also on the 650ss and the Vincent."

Has anybody else installed a 530 x ring on a Commando?
 
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The casting is very thick by the sprocket. Even if the chain takes a tiny bit out there in its first few times around, no harm. Both of my Nortons ran clear right off with the 530 vx.
There is also a special version of the 530x ring that is made for classic bikes with tight clearances. It is narrower than the DID vx 530.
I'll have to dig around to find the info

Glen
Hi Glen,
Any idea what the pin lenght is on these chains?
Are you in the BMOC Glen?
 
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You've used these Glen?
They really stack up against 530VX?
I haven't used these as the DIDvx530 fit on my MK3 easily. One of the VOC members has been running the RK uvw on his 1000 cc Vincent, no problem. I wouldn't hesitate to use it on an 850.
The 750cc recommendation means you could put it on a Kawi 750 triple which would stress the chain more than an 850 Norton.

Glen
 
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Hi Glen,
Any idea what the pin lenght is on these chains?
Are you in the BMOC Glen?
Hi Andy
I'm not in the BMOC at present.
Pin length on the DID 530 vx3 is .93"
Pin length on the RK uwv 530 is .89"

Here is a UK supplier that sells the narrow RK to US/Canada.
The price is a bit less than I paid for the DID, thats a surprise.

The RK uwv 530 has a tensile of 35k N
By comparison, unsealed Renold 530 has a tensile of 22k N

 
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mean gene

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To get back to the original question on machining rear drum break or sprocket, you must wrap the flat OD area with large rubber band or inner tube. Cast has a bad habit of wild vibrations when machining, the rubber band will cancel most of these
 
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Here is a UK supplier that sells the narrow RK to US/Canada.
The price is a bit less than I paid for the DID, thats a surprise.

The RK uwv 530 has a tensile of 35k N
By comparison, unsealed Renold 530 has a tensile of 22k N
Cheers Glen, appreciate the info.

To get back to the original question on machining rear drum break or sprocket, you must wrap the flat OD area with large rubber band or inner tube. Cast has a bad habit of wild vibrations when machining, the rubber band will cancel most of these
Now that's a trick I'd never dream of, will try that soon.
Cheers to you Gene.
 

baz

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Cheers Glen, appreciate the info.


Now that's a trick I'd never dream of, will try that soon.
Cheers to you Gene.
Another trick that's similar is sometimes if you are turning something that's resonating you can stuff a rag inside and wet it
Never tried it myself but an old tool maker mate told me this
 
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Re: "Here is a UK supplier that sells the narrow RK to US/Canada"
If you click on the link, it says they don't ship to Canada.
 

Burgs

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hi
Discs, forget trying to machine /turn the discs on anything other than a machine designed for doing this sort of work, I have tried and failed and I am a machinist and mech engineer.
People out there have the correct equipment, and are professionals at what they do, and at the end of the day it costs stuff all.
Blanchard grinding only does one side at a time, and the trick is you need to do both sides at once otherwise you will get pulsations back through the master cylinder/hand lever I know been there.
We have a couple of Blanchard grinders, and the time to setup the correct stones speeds ect would not make it efficient enough to make any money, maybe for a few hundred would be OK.

Drums, I machine my own on one of my lathes, no problem, what is most important is to machine the relined/new shoes to suit the drum after it has been machined to clean surface, I then set the backing plate up on the lathe true to the spindle, shim the cams so the shoes are around 10 to 15 thou bigger than the drum, then machine the shoes so they are a sliding fit in the machined drum, the aim is to get maximum contact of the linings to drum as possible, ie the greatest friction area shoe to drum.

My Penny's worth
Burgs
 
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Trying to turn down rear drum sprockets to fit a 520 and front discs to clean them up.
Anyone have any inputs on tool bits and feed rates? Tried hss and carbide bits and asstd speeds - having issues with chatter and poor cutting. Front disc is also an issue due to chrome finish and chatter. I could try milling but it may not be easier or quicker. I have a brake lathe that has not ben used for many years, but not yet thought of using it as I'm thinking that will not improve matters.
Cheers,
Andy
Hi Andy

I ran my MK3 rear sprocket at 350RPM with a cheepo Chinese carbide tip worked fine for testing a 520 setup.
 
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