Thread: Machining a Cast Wheel?

Originally Posted by PDW

$1000? That's somewhat high IMO.

If you were near my shop I'd do it for $100 provided:

it was cash

*and*

we met somewhere so you didn't know where I lived, so that if the wheel fell apart while you were riding it, there was no chance you could hold me responsible.

Otherwise I'd probably just say no, or ask a ridiculous sum to get you to go elsewhere. Problem is, in Australia with our liability laws, you can't sign away the right to sue even if an accident is easily foreseeable and a consequence of something you did knowing the risks.

That lathe would probably get the spacer done but not quickly or well, IMO.

PDW

PDW its a common thing to do these days check out this web site MOTARD WHEELS KTM DRZ400 WR450 HUSABERG KLR650 DR650SE with CBR250 cast wheels - supermoto wheels in Brisbane Queensland and the responsibility would be on me as im the one putting the bike together first ride could be a moment or lol

Originally Posted by gazza2009au

PDW its a common thing to do these days check out this web site MOTARD WHEELS KTM DRZ400 WR450 HUSABERG KLR650 DR650SE with CBR250 cast wheels - supermoto wheels in Brisbane Queensland and the responsibility would be on me as im the one putting the bike together first ride could be a moment or lol

I was serious in what I posted. Problem is you need someone with a pretty big lathe and those beasts are scarce. I'm fortunate enough to have one that can swing 28" in the gap.

Setting up the wheel to turn it would be a bit of a PITA due to its size/shape if it's a one-off. Turning it down is the trivial part.

If it were worthwhile and there were enough to do, I'd make up a spindle mounted mandrel to be a good fit on the wheel bearings to locate the wheel concentrically, then drive it via a bolt or similar in a face plate. Once the tooling was made, doing the turning is quick & simple. That's my first thought anyway.

My big lathe is in my Tasmanian shop so I'm not in a position to do anything for you. Good luck with it, though.

PDW

no worries PDW, the shop i mentioned that would do the whole wheel fitting for $1000 will do any machining i need done

If they have quoted $1000 for this as said it may be something they don't really want to do,or there is a lot more to it than just knocking the mounts down.

Originally Posted by gazza2009au

PDW its a common thing to do these days check out this web site MOTARD WHEELS KTM DRZ400 WR450 HUSABERG KLR650 DR650SE with CBR250 cast wheels - supermoto wheels in Brisbane Queensland and the responsibility would be on me as im the one putting the bike together first ride could be a moment or lol

Back to what i said on the first posting I did here.We are becoming a litigious country thanks to likes of some big ambulance chaser law firms that are evening news on the media.Is why I would eer on the fine side of''caution'' doing these jobs.There is always some ''bum'' out there will do these jobs for a quick quid with no care and responsibility.Worse off they usually are void of assets to claim should litigation occur.
Finally you cannot guarantee what or where the [in this case] rider or owner will do.We have a legal obligation here in Victoria when inspecting a m/cycle to be looking for modification.Also tyre depth must be measured in company with the presenter of the machine and the time recorded as well.Been cases where 9 am tyres were ok at 4pm same day the bike off the Gt Ocean rd with no tread left and a dead or maimed rider.So it boils down to C Y A in these circumstances[cover your a.....se] .John.

I could swing it without the tyre, but I'm too far away. How much does the rotor need to come in? Is it an option to remount the caliper instead? Is it an option to space the whole wheel across? A few mm shouldn't be a problem.

A grand sounds like a lot, but I guess they're covering themselves for unforseen headaches - as well as making it worth their while. Personally I would be finding a cheaper way.

PS: You didn't use the word 'billet' by any chance, when talking to that machine shop?

Where abouts in NSW are you, it's rather large!

Can think of one person at least outside the metropolitan area who does large car racing wheels and that looks like a piece of p in comparison unless there's something obvious I'm not picking up. Whether he's inclined to do it, couldn't answer.

There is another possible option that is worth consideration. Get a hold of a swingarm that suits the rim you have and modify the swingarm to fit your frame. It's generally easier and safer to do it this way. Most swingarm mods only require basic hand tools and maybe a welder. If you choose a steel swingarm it is easy to weld with a normal stick welder. Even if you have to make the entire pivot tube and weld it on it's not that difficult provided you mock it up in position and align it all correctly then tack it up.

If you can find a swingarm that is slightly narrower than your frame then you only need a spacer. I've often seen complete swingarm and wheels off roadies on ebay for less than $100, especially steel ones.

I totally understand why engineering shops don't want to do these mods as it can easily end up in their lap if things go pear shaped. You can also get some more advice/tips from bike modding sites like streetfighters.com.au as they have guys that are doing these types of mods all the time.

Steve

ok lets clear this up the $1000 i was quoted is from a motorcycle engineer in sydney he mentioned he has "done heaps" (actually shop owners words) of these modded bikes but they have only done the XR650's for racing mine is a baby 250cc so its a little different, ive also been to this shop in person and had a crankshaft rebuilt by these guys and they know there stuff

the thing is with modding the road wheels to fit a dirt bike is all about alignment the wheels need to be centered and also the disc brakes needs to be centered otherwise it could turn awkward or even the brakes could lock up if not done properly but keep in mind this isnt brain surgery and if i go a head i will be using a laser light to align the wheels for precise measurement for machining

than there is the test riding people dont just jump on the bike and go YEHHHHHHH HAAAAA, there will be gradual steps taking to ensure the bike handles ok before its ridden to full potential, i do have over 20 years of motocross and road riding skills guys so im not a noob

this is the part needing machining its a sprocket carrier the section in the square needs to be machined all around and from the sprocket side in 10mm

also can someone point me to a dealer in oz who sells the harbour freight 7x10 metal lathe?

Well the sprocket carrier is a lot smaller and easier to machine than a whole rim. Guess we wasted some time on that.
So how thick are those lugs, 20mm? You want to halve them?

Originally Posted by Bryan

Well the sprocket carrier is a lot smaller and easier to machine than a whole rim. Guess we wasted some time on that.
So how thick are those lugs, 20mm? You want to halve them?

its about 20mm i do have a tig welder i can build up the back so that isnt a problem

machining the sprocket carrier has been done check out post 5 here CBR wheels on XR600 - XR600/650 - ThumperTalk

im thinking i could just buy a XY milling table and use a drill press to machine it

go for it

Originally Posted by gazza2009au

machining the sprocket carrier has been done check out post 5 here CBR wheels on XR600 - XR600/650 - ThumperTalk

im thinking i could just buy a XY milling table and use a drill press to machine it

As long as machining the sprocket carrier back doesn't go far enough to need to move the bearing recesses in the hub, no huge dramas. Still need a big lathe because the whole wheel needs to turn. I was assuming only the hub needed to be modified anyway, not the rim.

As for using a drill press as a mill, good luck with that idea. Many have had the same thought, almost none have ever succeeded in doing anything other than breaking tooling and damaging parts.

A drill press spindle is NOT designed to take side loads. Putting a side load on a Morse taper shank is a guaranteed way to get it to release. That's why mills with Morse tapers also have hollow quills and the tooling is restrained via a threaded draw bar. Drill presses just have tanged shank recesses. Put a side load on a tool in one and it will release.

Not to mention it'd need to be a pretty good sized X-Y table anyway and then you find the (lack of) rigidity of the drill press table with a pile of cast iron, then clamps, then your wheel, mounted up, all cantilevered out. Got a good dial indicator to check the hub is at right angles to the drill spindle? How about a rotary table to get it to spin, or were you planning on rotating the drill press table with the XY table bolted on top?

By the time you rig this lot up and buy all the bits then see it doesn't work, the $1000 for a pro to do it is going to look cheap. I say this as a person who'd FAR rather buy tools than pay someone else to do anything, too.

As for a HF lathe, they're just generic Chinese manufactured junk same as what you can buy on Aussie Ebay. No reason to not buy from one of the local suppliers if that's what you want. Take a hike to Hare & Forbes, get an idea of what you get for your dollars first. I dropped by there the other day and let's say I was underwhelmed with the fits.

This is a very do-able job, don't think I'm trying to say it's not. But you either need a big mill or a big lathe simply due to the wheel diameter.

PDW