2 weird 2 live, 2 rare 2 die.
Pulled the front wheel this morning, the brake disc is pretty lumpy, so will see what I can do at work to give it a skim. The wheel bearings and seals are STUFFED ! I think only the brake was holding the front wheel straight. With the brake removed and holding the bars steady, there was about 5mm playat the edge of the wheel.. Dodgy..
So new bearings/seals are in order. A wee spacer where the speedo drive used to sit to be turned up. Skim the disc.. Good fun
Originally Posted by sil3nt
2 weird 2 live, 2 rare 2 die.
So today after work I get to having a go at the front disc. Not as easy as you would think.. I'm not going to bother with a regular ass tpmr tip tool, or grind up a piece of assab. I've made a fixture so the disc will sit in nice and snug, then held in place with the lathe tail stock. I've pulled out the old tool post grinder that most people didn't even know existed ha. Found a reasonable cup wheel for it and had a test run today. Considering it spins at 4,500 rpm and has no guard, I'm going to make a guard so I don't lose my face if it explodes..
I've also decided to replace the front axle with a custom job, That has the necessary threaded holes for attaching crash bungs..
Watch this space.
Forum whore
I must be drinking am seeing double
"Instructions are just the manufacturers opinion on how to install it" Tim Taylor of "Tool Time"
Saying what we think gives us a wider conversational range than saying what we know. - Cullen Hightower
Forum whore
i see it too!, maybe we should both attend AA?? ahahha
2 weird 2 live, 2 rare 2 die.
I has no ideas what you's is on abouts..
Long Haired Yobbo
I'm watching with interest!
Heinz Varieties
2 weird 2 live, 2 rare 2 die.
Soo, today I took the day off to mess around in the work shop. Welded up a fixture and fixed that in the chuck, turned it so it was flat. Fitted up the tool post grinder. A whole bunch of little issues getting that set, but persistence pays off.. Front disc is now nice and clean. No gnarly lip or gouges. Obviously I have no motor so can't test it at all. Started on the new axle as well but ran out of time.. Maybe will have it done next friday..
Long Haired Yobbo
Nice, Im going to have a go at that myself very soon.
Heinz Varieties
Long Haired Yobbo
Is there any reason you went for the grinder? better finish in a quicker time?
I've been pissing about with an old disk in the lathe and HSS seems to cut it OK but its quite fussy to get a good finish. Oh, and the factory disk was really far from concentric!!
Heinz Varieties
2 weird 2 live, 2 rare 2 die.
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
Why Not???: MNZ975.
Nice Work Gatch.
I didn't think that it would be that difficult... Now I see why everytime i get things machined it costs the earth.
(Its the time and thought that you guys have to put into it to acutually get the stuff done).
Sounds like you have access to some equipment.
111000101000100010011110
reckon that technique would work well with warped discs? I'm guessing with the light pressure needed the high spots probably wouldn't be pulled back down like they would in a surface grinder.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
2 weird 2 live, 2 rare 2 die.
Na most of out stuff it pretty basic.. We just have to think outside the square to get things done..
Depends how warped they are to start with I guess ? I thought about getting them ground on a surface grinder, but the rivets the hold the disc to the carrier get in the way.. I'm not sure about the strength of the magnetic chucks..
111000101000100010011110
bout .1-.15mm runout, good point bout the rivets, theyd have to come out before using on a surface grinder
2 weird 2 live, 2 rare 2 die.
I don't think .15 would cause any problem.. You'll be grinding both sides so any imperfections should be ironed out.. Yeah I didn't want to mess with the rivets so did it on the lathe..
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