A question for the Engineers on the site

**Crasherfromwayback** · 7th October 2012, 16:15

Long story short. I need a clutch cover and waterpump housing made for a bike that they're not avail for. Is there any foundry in NZ you know of that'd do one offs like that in magnesium I can trust to do it right? Alloy if need be.

Ta.

Pete

**tigertim20** · 7th October 2012, 16:21

hayd3n worked at the foundry down here a few years ago, he may know more details around what they can or cant do.

what are your dimension? any reason you cant get it machined out of billet alloy or is that a cost issue?

**Crasherfromwayback** · 7th October 2012, 16:23

Originally Posted by tigertim20

hayd3n worked at the foundry down here a few years ago, he may know more details around what they can or cant do.

what are your dimension? any reason you cant get it machined out of billet alloy or is that a cost issue?

I'll track him down and PM him. Cheers for the heads up. Short story longer...it's for the SR500 I have coming (the bike in my avatar). Ain't no bits floating round for them...Kawasaki only built four of 'em. I don't want billet bits...I'm really anal about shit being correct. Especially on such bikes.

Chur.

**schrodingers cat** · 7th October 2012, 17:23

Do you think the original was gravity sand cast or pressure die cast?
It would be quite involved to produce the pattern and get a good quality gravity casting.

Why not billet then sand or shot blast to get to appearance right?

**Crasherfromwayback** · 7th October 2012, 17:28

Originally Posted by schrodingers cat

Do you think the original was gravity sand cast or pressure die cast?
It would be quite involved to produce the pattern and get a good quality gravity casting.

Why not billet then sand or shot blast to get to appearance right?

Not sure which method they'd use for the originals mate.

Guess we could do that...but would've thought the finish was hard to duplicate? Also thought the cost would be worse?

**Ocean1** · 7th October 2012, 18:36

Originally Posted by Crasherfromwayback

Not sure which method they'd use for the originals mate.

Guess we could do that...but would've thought the finish was hard to duplicate? Also thought the cost would be worse?

Depends on numbers, more than a few hundred and they'd probably be die-cast, less than that may have been shell molded. Don't matter, you can't afford the first and the results of the second are indistinguishable. You just have to make a pattern out of treewood/bog. Call Borren Metal Forming in Paraparaumu, (04-298 5034), think they're still into shell molding.

Oh, and the cost is going to be bad however you do it mate, CNC milling it from a lump and blasting it doesn't require any one-off tooling. And it'd be stronger for the same weight. Which raises the question: how can you describe the original shape?

**Grumph** · 7th October 2012, 18:56

The foundry in Nelson which does the gearbox cases for TT Industries is accustomed to working in Elektron which is what you'd use.

I understand they do a fair bit of one off work too.

**neels** · 7th October 2012, 19:00

There is an outfit in chch that does custom casting, the old man has had them make various bits for his vintage cars, do you have originals to make moulds from?

**Crasherfromwayback** · 7th October 2012, 19:11

Originally Posted by Ocean1

Depends on numbers, more than a few hundred and they'd probably be die-cast, less than that may have been shell molded. Don't matter, you can't afford the first and the results of the second are indistinguishable. You just have to make a pattern out of treewood/bog. Call Borren Metal Forming in Paraparaumu, (04-298 5034), think they're still into shell molding.

Oh, and the cost is going to be bad however you do it mate, CNC milling it from a lump and blasting it doesn't require any one-off tooling. And it'd be stronger for the same weight. Which raises the question: how can you describe the original shape?

Dunno how many KHI would've made...doubt it was too many. Really appreciate your help and thoughts. I will more than likely be able to get the itmes I need from a geezer in Aust that has the same bike. He wants my spare SR250 engine real bad...and will swap me most of an SR500 engine. It's that engine I need the cases for.

Originally Posted by Grumph

The foundry in Nelson which does the gearbox cases for TT Industries is accustomed to working in Elektron which is what you'd use.

I understand they do a fair bit of one off work too.

Awesome. Many thanks.

Originally Posted by neels

There is an outfit in chch that does custom casting, the old man has had them make various bits for his vintage cars, do you have originals to make moulds from?

Really appreciate the heads up. I'll get it touch with them.

**bogan** · 7th October 2012, 19:12

I seem to recall the auckland uni guys getting some parts done by lost foam casting. The foam gets machined to shape, the put in a sand mold, the foam fucks off as the metal goes in. With savings on magnesium compared to the CNC billet approach it might be worth looking into if you don't have an original part to pull a mold from.

**Ocean1** · 7th October 2012, 19:17

Originally Posted by bogan

I seem to recall the auckland uni guys getting some parts done by lost foam casting. The foam gets machined to shape, the put in a sand mold, the foam fucks off as the metal goes in. With savings on magnesium compared to the CNC billet approach it might be worth looking into if you don't have an original part to pull a mold from.

Good trick eh? An updated version of the lost wax method.

Unfortunatley not the best for thin-wall sections, no sand casting method is really.

**Crasherfromwayback** · 7th October 2012, 19:18

Originally Posted by bogan

I seem to recall the auckland uni guys getting some parts done by lost foam casting. The foam gets machined to shape, the put in a sand mold, the foam fucks off as the metal goes in. With savings on magnesium compared to the CNC billet approach it might be worth looking into if you don't have an original part to pull a mold from.

That's cool. I will have the original part...so maybe that'll help. I will settle with alloy too if mag is too expensive.

**Crasherfromwayback** · 7th October 2012, 19:20

Originally Posted by Ocean1

Good trick eh? An updated version of the lost wax method.

Unfortunatley not the best for thin-wall sections, no sand casting method is really.

Yeah it is! I remember doing sand casting at Naenae College in metal work class. Loved it. Didn't love getting cracked over the head with a soldering bar for talking while the teacher was though. Fucking hurt.

**AllanB** · 7th October 2012, 19:22

I've used the Casting Shop in CHCH (Watts Rd) to make some one off custom parts for my bike from patterns I made - came out well and they were very helpful.

**Crasherfromwayback** · 7th October 2012, 19:25

Originally Posted by AllanB

I've used the Casting Shop in CHCH (Watts Rd) to make some one off custom parts for my bike from patterns I made - came out well and they were very helpful.

Cheers for that. I'll get it touch with them. Really appreciate the help.