Repro Aluminium finned brakes

[metric_thumbs]

Is there a supply of the aluminium drums so characteristic of 356's.?
I ask as many people in the VW world would like them for the period recreations of performance Beetles.
Safe original drums are already like hens teeth, so is someone reproducing them?

Do you know if along with the drum, if the complete backplate assembly is available?


Thanks.

 

[HendrikMoulds]

I don't think anyone reproduces these. Would be very hard to do and expensive.

 

[metric_thumbs]

I thought so too. But 911 world (?) magazine implied in their 356 article casually mentione dthey were available repro.

Am I guilty of believing what is in a magazine?


Does this indicate a gap in the market.
If I had made perfect copy drums - which ever is the most desirable - say Super 90s - how much would they go for?
When I say perfect copy I mean they would look exactly correct but no Porsche copyright markings or details.

I have made parts for classic cars before and the drums do not look so difficult. Am I missing something?

 

[HendrikMoulds]

But did they say where you could get them repro?
I don't know how difficult they would be to copy, just am pretty sure no one has done so so assumed there were problems. As far as I am aware the drums are all the same for 356 Bs. Don't know how much they could be sold for though, it might be worth speaking to one or two of the parts suppliers here in the UK.

 

[metric_thumbs]

No the magazine did not say.

I have looked at some drums in detail and reckon there is no technical difficulty. Just commitment to get the patterns made up and some casting time, and some machining time.

 

[912UK]

I knew the Bently guys have new drums made and I know the guy who makes them Small workshop in Havant. I am sure they could be made but to have fins as well no.. not unless they where either cast or CNC machined both could be done but a HUGE cost!!


My machinest days are on hold but they could be made from a billet but the cost of a billet is not cheap, if you can imagin the way Bentlys have groves it could be done..

 

[metric_thumbs]

You mean W O Bentley as in Bentley 3 litre?
Do not forget their fins were circumferencial - and 356 are radial - or again am I wrong.?

 

[vitesse]

Do they have cast iron inserts like the original "Minifin" ones that used to be available for --Mini's?The best way would be Gravity die cast but the tooling could cost £5000.Sandcast would be reasonable with a resin pattern/corebox around £650,with castings in LM6/LM25 around £20ea plus the CI inserts.Then you have to add the machining cost,probably ,as much again.

 

[Robin]

The original 356A brake drums had circumferential fins the 356B had the radial fins. Both of these brake drums were made using the original Al-Fin patent method of overcasting an aluminium drum over a steel band which formed the actual friction surface. Have a look on Google " Al-Fin Porsche 356 Brake Drums " to read the 1998 story of one person (P L Albrecht ) in USA who looked at remanufacturing them. There is also an interesting article in 356 Registry magazine Volume 25 number 3 page 41 which describes how the drums were remanufactured without infringing the Whitfield and Seshunoff patent later granted to the Al-Fin Corporation of Farmingdale NY. These drums were only made in the 60mm wide form used on the Spyder rather than the 40mm size used for the 356A and B so were quite special, they do not say how much the cost of making them was! If you Google " Al-Fin " you will find Al-Fin pattern brake drums are being made for Triumph Spitfire and also for early MG's

 

[metric_thumbs]

ORIGINAL: VITESSE

Do they have cast iron inserts like the original "Minifin" ones that used to be available for --Mini's?The best way would be Gravity die cast but the tooling could cost £5000.Sandcast would be reasonable with a resin pattern/corebox around £650,with castings in LM6/LM25 around £20ea plus the CI inserts.Then you have to add the machining cost,probably ,as much again.

I like your metallurgy! []
I was thinking of LM25 in oil sand - normal green sand to fill the box but oil sands for teh surface of the casting. FOSECO do the right stuff. Correctly runnered I recon you could produce a very good job, with little fettling and good pick up points for accurate machining datum - so little scrap.

 

[metric_thumbs]

ORIGINAL: Robin

The original 356A brake drums had circumferential fins the 356B had the radial fins. Both of these brake drums were made using the original Al-Fin patent method of overcasting an aluminium drum over a steel band which formed the actual friction surface. Have a look on Google " Al-Fin Porsche 356 Brake Drums " to read the 1998 story of one person (P L Albrecht ) in USA who looked at remanufacturing them. There is also an interesting article in 356 Registry magazine Volume 25 number 3 page 41 which describes how the drums were remanufactured without infringing the Whitfield and Seshunoff patent later granted to the Al-Fin Corporation of Farmingdale NY. These drums were only made in the 60mm wide form used on the Spyder rather than the 40mm size used for the 356A and B so were quite special, they do not say how much the cost of making them was! If you Google " Al-Fin " you will find Al-Fin pattern brake drums are being made for Triumph Spitfire and also for early MG's

Thanks for this - I knew AlFins as I am a brummy and they were made in Aston.
Did not know it was a patent method for the steel liner. I reckon now it would be steel. If you were producing thousand cast iron would be cost effective and possibly more friction.

I will take a look at the Albrect article.

But still I am surprised that no one has started to re-manufacture them again.

 

[912UK]

there is a need for them world wide that's for sure. The race boys can't get enough of them talk with Mike at PRS

This is where Porsche should step in or alow some one to make them. They like the cars at the shows so inorder for them to get there they need to be able to brake!!

The only thing is if Porsche did make them then the mark up would make it not cost effective to buy it as usual takes a smaller opertaion to make them and take the huge cost on board and hope in time they get there out lay back and then some profit.

 

[vitesse]

ORIGINAL: metric_thumbs

ORIGINAL: VITESSE

Do they have cast iron inserts like the original "Minifin" ones that used to be available for --Mini's?The best way would be Gravity die cast but the tooling could cost £5000.Sandcast would be reasonable with a resin pattern/corebox around £650,with castings in LM6/LM25 around £20ea plus the CI inserts.Then you have to add the machining cost,probably ,as much again.

I like your metallurgy! []
I was thinking of LM25 in oil sand - normal green sand to fill the box but oil sands for teh surface of the casting. FOSECO do the right stuff. Correctly runnered I recon you could produce a very good job, with little fettling and good pick up points for accurate machining datum - so little scrap.
quote]
I was thinking either airset or better,amine set using a modified core blower producing 2 at a time in flaskless moulds on a 4/5 minute cycle.The inserts would have to be cast as a ring with lugs to hold them in and a print in the mould;never made brake drums so a sample to work to would be necessary(never made drums with insert,have made plenty of special CI drums.