15 replies to this topic

[Karl]

Hi all,

Does anywhere know of a decent, reliable and preferably cheap brass turning service? I only need a set of rammers making, one solid and one hollow (5/16" dia).

Cheers,
Karl

[Rip Rap]

Hi all,

Does anywhere know of a decent, reliable and preferably cheap brass turning service? I only need a set of rammers making, one solid and one hollow (5/16" dia).

Cheers,
Karl

PM sent.

[dave]

PM sent.

any reason not to disclose ?
i am trying to get some tooling made at the moment, awaiting quotations

dave

[Bonny]

any reason not to disclose ?
i am trying to get some tooling made at the moment, awaiting quotations

dave

Try talking to your local machine shops, I'm sure you can get a few quotes that way.

[www.oliverbrown.co.uk]

How much is bespoke tooling, 3/4" complete set for instance? Only seen the poor sets that sel on ebay.

[dr thrust]

i have been toying with the idea of a British based pyro tooling service for a good while now.
standard and custom tooling, the full shebang, star plates, gerb,rockets,fountains, even clamshells but dont know if there would be enough demand, to justify the £ 7000+ set up costs of tooling?

[dan100]

i have been toying with the idea of a British based pyro tooling service for a good while now.
standard and custom tooling, the full shebang, star plates, gerb,rockets,fountains, even clamshells but dont know if there would be enough demand, to justify the £ 7000+ set up costs of tooling?

clamshells?
it would be good if you had access to a bigger shop without having to lay out the cash but from what i gather ss [if chosen]needs expensive carbide cutting bits that wear after a few sets. i dont think there is a great deal of demand to justify the layout either, however ive seen the cheap tooling and it aint cheap for what it is i could make a basic set for a tenth of the cost but it will be that-basic ive been trying to butter someone up abroad who makes the nicest looking tools ive seen but then shipping and material would see me paying high prices.
ive sketched a couple of sets of tools myself with a universal base and a few sets of spindles and rammers and am at the stage of presenting them to machinists we'll see what happens im sure someone would enjoy this break from the norm work but again pricey for one off's
, star plates can be suprisingly expensive aswell.
the tooling could be a sideline if you persue this venture on any scale im first in line.

dan.

[dr thrust]

a clamshell ,is just the generic name for a two piece, bolt together aluminum tube support, used when pressing rocket motors, all the major players have them, wolter,and firesmith-tools but there really pricey+ shipping.
plus i have a few designs for tooling of my own, you can see one opposite in my avatar its a former to make headers for 1940's standard rockets, retro rockets are fun

Edited by dr thrust, 18 July 2011 - 04:56 PM.

[Karl]

a clamshell ,is just the generic name for a two piece, bolt together aluminum tube support,

Sorry to hijack my own thread but rather start a new one ...

I understand the advantages of using clam shells as i've seen quite a few of my tubes start to bulge & split when compacting the nozzles. Say if I rammed a rocket (Ooo er!) whilst using a clam shell yet I know without it the tube would fail and rupture, surely the pressure from the rocket igniting would finalise the failure?

I've not read the pro's and con's of tube supports yet so pardon my ignorance

[Bonny]

Sorry to hijack my own thread but rather start a new one ...

I understand the advantages of using clam shells as i've seen quite a few of my tubes start to bulge & split when compacting the nozzles. Say if I rammed a rocket (Ooo er!) whilst using a clam shell yet I know without it the tube would fail and rupture, surely the pressure from the rocket igniting would finalise the failure?

I don't think so, or nobody would be using clamshells.

[digger]

Sorry to hijack my own thread but rather start a new one ...

I understand the advantages of using clam shells as I've seen quite a few of my tubes start to bulge & split when compacting the nozzles. Say if I rammed a rocket (Ooo er!) whilst using a clam shell yet I know without it the tube would fail and rupture, surely the pressure from the rocket igniting would finalise the failure?

I've not read the pro's and con's of tube supports yet so pardon my ignorance

They are used so that you can get good consolidation of the powder in the motor. This will ensure that you get an even burn of the grain by eliminating soft spots and voids. With the aid of a pressure gauge on your press you can then press to the same pressure every time, and once a suitable grain / nozzle / powder combination is found you will get a consistent rocket every time.

This has nothing to do with your nozzle design / grain design / powder composition so has no effect on CATO's other than eliminating grain defect CATO's.

As a quick P.S. we needed some tube supports for a project that we have just done, we did not have time to make clamshells up so we just machined a smooth hole in solid bar (leaving an inch around the tube). When we finished pressing the device we then just ejected it using the press to push it out pressing down on the comp (sat on an ejection sleeve). It worked very well with no damage to the tube and it was far cheaper and much quicker to use.

[dan100]

thanks for clearing that up ive seen them used and sold but never heard the name.
i use a method similar to what digger describes with a tube support sleeve but they can be trouble to remove.

dan.

[parabolic]

Gareth,

was thinking of making the same, a smooth hole in solid bar then push it out. But is your wall thinkness of 1" a little on the thick side?

[digger]

Gareth,

was thinking of making the same, a smooth hole in solid bar then push it out. But is your wall thinkness of 1" a little on the thick side?

Yep the 1" wall thickness is excessive for metal. What I did not say was that it was Nylon 66 as it is very quick to machine. The tool did not have to be made to last forever, however I guess it should have a decent life.

[parabolic]

that's an even better answer as I was thinking that too. Nylon or some other plastic I thought would be ok but have to be careful that the tube can't bulge into the plastic causing it to stick, so a good wall thickness like you have done would be good,

I did think about using casting resin with perhaps sand as a filler/bulk agent and fill a block around a smooth metal mandrel with release agent. We use a lot of stainless steel devcon resin for bedding rifles but at £30 a pop for 500g of devcon i'm sure the casting resin option might be more affordable.