Bucket rules (or lack, thereof)?

[speedpro]

I used a similar technique to mount and turn some clutch plates I was thinning but I ground and polished a HS steel tool for the cut. Made a really nice cut, no vibration, and a nice finish. Turned it a bit faster of course. Had a bit of success with my electric high speed grinder mounted on the tool post machining some hardened surfaces. Very slow material removal but beautiful finish.

[gatch]

I used a similar technique to mount and turn some clutch plates I was thinning but I ground and polished a HS steel tool for the cut. Made a really nice cut, no vibration, and a nice finish. Turned it a bit faster of course. Had a bit of success with my electric high speed grinder mounted on the tool post machining some hardened surfaces. Very slow material removal but beautiful finish.

Yeah if you can set up the grinder properly it will give the best finish.. I only had one wheel that was applicable to what I was doing and was slighly unbalanced I think, left slight vibration marks on the disc, but you cant feel any imperfection with your finger.. Good enough for the application I think.

[Ocean1]

Yeah if you can set up the grinder properly it will give the best finish..

Good job. They're originally finished with a cup wheel, you can see the machining marks clearly on most new disks.

I had trouble with my front disk pulsing at certain speeds, getting progressively worse. It's a known occasional Buell issue and there's as many "fixes" as there are "experts". Measured up in spec' (just) for run-out but nothing else worked so I ground my disk absolutely flat with a diamond cup wheel on a mill, (no rivets to worry about). It helped but didn't eliminate the problem.

In the end I didn't have time to piss around with it any longer, teh scooter centre replaced the disk under warantee () and the problem went away. Would love to know what the problem with the old disk was...

[koba]

I've never used a tool post grinder before.. So thought I'd have a go.. The tool steel might work if you can deal to the vibration, and the problem of intermittent cutting because of all the holes in the brake disc..

To hold it, I welded a bit of 10" pipe, to a 12mm thick mild steel disc, with an OD of about 340mm. Then held the pipe in the chuck jaws (you will never get the brake disc to run true just holding it in a chuck, even in a 4 jaw you will have vibration problems etc), I bored the 12mm thick bit out so that the brake disc carrier and rivets would fit inside it.. Then bored a spigot into it that was about 0.2mm bigger than the OD of the brake disc, so that it would run concentric. THEN used the tail stock to hold the brake disc in the centre, up against the machined fixture. It only needed light pressure because with the grinder you are only removing about 0.05mm at a time. I had the lathe turning as slow as it would go (45rpm) with the maximum feed I could. The grinder spins at 4500rpm I think. Lots of really watered down coolant..

Easy peasy

I experimented a bit with an angle grinder today, looks promising for what I'm trying to do.

Nice!

Smart bastard aye!

[gatch]

I experimented a bit with an angle grinder today, looks promising for what I'm trying to do.

Nice!

Smart bastard aye!

hahahah an angle grinder you rough prick !!

I guess if you can hold it rigid on the tool post it could work.. Tell me how you get on..

[speedpro]

One of the guys flicked a pushrod out of place at the drags. It wasn't any good afterwards and the only spares anyone had were too long. We fitted one end of a new one into a cordless drill and ground the end off. The guy with the cordless drill smeared one hand with grease and used that to steady the pushrod while it was spun. Once it was squared up and the correct length we fitted the end bit and put it back in the motor. Did another good run up around 200mph. Rough? maybe. Did it work? Certainly did.

[NOID]

yep rough but it works .. Grinder, hammer and welder and anything possible

[koba]

One of the guys flicked a pushrod out of place at the drags. It wasn't any good afterwards and the only spares anyone had were too long. We fitted one end of a new one into a cordless drill and ground the end off. The guy with the cordless drill smeared one hand with grease and used that to steady the pushrod while it was spun. Once it was squared up and the correct length we fitted the end bit and put it back in the motor. Did another good run up around 200mph. Rough? maybe. Did it work? Certainly did.

That is bloody brilliant!!!

[F5 Dave]

With rivets on a mag table apparently you can use a spacer but it is a pain. If you use too much magnet the disc is pulled straight & springs back after you make an ineffective cut. -or so I'm told, I pay to get those done, usually a band-aid till you get some more discs. Though I have straightened discs that lasted for many years racing on the wheel with crescent wrench & taps of hammer. Good luck required.

If the disc is straight & it's just grooves then a sand paper flapper wheel on the disc grinder while disc spun on lather works well, even sandpaper can be ok to deglaze & get rid of minor grooves.

[gatch]

With rivets on a mag table apparently you can use a spacer but it is a pain. If you use too much magnet the disc is pulled straight & springs back after you make an ineffective cut. -or so I'm told, I pay to get those done, usually a band-aid till you get some more discs. Though I have straightened discs that lasted for many years racing on the wheel with crescent wrench & taps of hammer. Good luck required.

If the disc is straight & it's just grooves then a sand paper flapper wheel on the disc grinder while disc spun on lather works well, even sandpaper can be ok to deglaze & get rid of minor grooves.

Flap wheels can fix almost anything..

[koba]

With rivets on a mag table apparently you can use a spacer but it is a pain. If you use too much magnet the disc is pulled straight & springs back after you make an ineffective cut. -or so I'm told, I pay to get those done, usually a band-aid till you get some more discs. Though I have straightened discs that lasted for many years racing on the wheel with crescent wrench & taps of hammer. Good luck required.

If the disc is straight & it's just grooves then a sand paper flapper wheel on the disc grinder while disc spun on lather works well, even sandpaper can be ok to deglaze & get rid of minor grooves.

My Brother used to do it by hand on a brake machine, just to break the ridges off.

Hold on this is KB I need to work on getting the braiks wronger.

Flap wheels can fix almost anything..

How I got on.

Conclusuions, lessons:

1. Gatch is correct about vibration and mounting.
2. Freehand grinder no good for actually reshaping the disk.
3. Angle grinder would probably work brill if mounted solidly.
4. Flat disk = easy, straight bolt to faceplate!
5. A bit of card under worn part of disk minimises vibraton.
6. Disk cut nicely with minimal marks with HSS bits.

I will probably carefully run a flapdisk over it to get "the look"

My other lesson was to fucken bloody measure everything, part 892.
When will I ever learn that one!

[gatch]

My other lesson was to fucken bloody measure everything, part 892.
When will I ever learn that one!

Good work. So long as its flat and parallel to the spigot it sits on, doesn't really matter how its done.. If all machining was straight forward and easy I wouldn't have a job..

Now now, I finished off the replacement front axle for the spada. It's got a 14mm hole right through it so is only marginally heavier than stock. Except for the ends are different, the retaining thread is now external. There is also an m10 thread in each end for holding crash bungs. The OD where the bearing sit is 19.98 - 19.99, where the oem item was 19.8 something ! Shocking tolerance.. Made from 4140 I am certain I will struggle to bend it.. The new one is at the bottom..

[speedpro]

4140, ppffft, I've snapped an axle made from that, mind you it was the rear axle in my bucket sidecar. We went on to some stuff they make drag race axles from. Then we broke the hub which was 41??. Got quite exciting.

[gatch]

4140, ppffft, I've snapped an axle made from that, mind you it was the rear axle in my bucket sidecar. We went on to some stuff they make drag race axles from. Then we broke the hub which was 41??. Got quite exciting.

If you are breaking stuff in 4140, its either made too thin, or hasn't had stress raisers removed.. Its good stuff..

[Skunk]

4140, ppffft, I've snapped an axle made from that, mind you it was the rear axle in my bucket sidecar. We went on to some stuff they make drag race axles from. Then we broke the hub which was 41??. Got quite exciting.

That sidecar may be making an appearance at the Easter Meet at Kaitoke.