50 replies to this topic

[cplmac]

Well I made a couple of spindles yesterday and today, my first try but I think they came out pretty decent. I need to mount them on bases but otherwise they are ready for pressing. One is a 3lb whistle (1") and the other is a 6lb (1.5").

Both spindles looking at bottom

Front view next to corresponding whistle spindles

[dr thrust]

nice,whats the dark one on the left made of?

Edited by chris m, 22 May 2009 - 03:40 PM.

[cplmac]

The spindles on the far left and far right were purchased from Rich Wolter, the left is a 3lb strobe spindle, and a 6lb strobe on the far right. The 3 is made with aluminum and the 6 is made with stainless steel. I just put them in the picture for reference to the whistle spindles I machined that are next to the strobe spindles.

[dr thrust]

good job !how long did it take to turn them? and that 6lb's a monster!!

Edited by chris m, 13 May 2009 - 08:48 PM.

[cplmac]

It took about 2-3 hours to turn each one, my lathe is nothing special. I picked up some 600 and 1200 grit and polished them up a bit, still think I'm just going to need to make another set. I fired one of the 6 pounders off tonight, the video is up in the handful of rocket videos thread.

[dr thrust]

hi as ever playing catch up, heres a hybrid 3lb spindle made on a 1930,s lathe! similar to a whistle spindle, half id, but longer for thrust two and a half inch long

and if you have a spare five mins with nothing better to do, which i guess you haven't because your reading this! check out the vids of me making it( my first go on a lathe) ho anybody know a good cutting fluid, cooling for ali an old boy said paraffin. tapering the spindle and parting off

Edited by chris m, 14 November 2008 - 05:29 PM.

[wjames]

aye, paraffin works just fine......so does machine oil.

[pyrotechnist]

How do you get it to cut the bar like a cone shape?

[dr thrust]

hi, i guess your asking about the taper?, well im just learning about the lathe myself!, here a link that explains cutting tapers better than i could ever do! turning tapers, i basically angle the top compound slide slightly away from the bar and this forms a taper, if you kept at it it would end up as a point, i found info on core design here on the creagan site tooling

as a point of interest if you are unable to cut tapers he is experimenting with "stepped spindles" to squeeze out every last drop of power without a Cato, certainly looks like an interesting development of core design which i will be investigating

Edited by chris m, 07 October 2008 - 06:27 PM.

[wjames]

i saw a "snowflake" shaped core once........complicated thats for sure.....

[Arthur Brown]

Yes special cores are sometimes used BUT with limited machining facilities the tools are difficult.

Here are people asking about turning tapers, while exotic core profiles need exotic cam profiles cutting possibly with a taper too, and to a really high standard of surface finish.

[dr thrust]

no snowflakes here im afraid,no tapers to, i made the "tri core" from the creagan site, hard to film it went like a bat out of hell, ho here's a "boring movie" tooling

[dr thrust]

hi heres the result of all those dull lathe videos we have a 1lb stepped whistle spindle, a 1lb bp nozzle-less spindle, a 3lb stepped whistle spindle, then 1lb whistle, 3lb hybrid spindle(work in progress) and 3lb whistle spindle all fit the same base, and basically i want to see how the stepped spindles perform against normal tooling.
on the 1lb nozzle-less bp spindle (center) theres a small step which i intend to use one increment of whistle for extra lift then the rest in bp.

[cooperman435]

Chris with the different burn rates of the bp and whistle would you expect the whistle increment to create a problem that one of them burning faster than the other would result in side burn of the slow propellant increment

[dr thrust]

hmm, thats an interesting point phil, and the answer is.. i really dont know i intend to do some ground testing of motors first to see what happening( theres no substitute for practical experimentation) with the nozzle-less bp (the one fixed in the ali base) the first increment of the whistle fuel grain is only 4mm wide and forms a wider hole for the bp on top to burn through and should burn up instantaneously giving extra lift. or i could be talking bo++ocks? its all part of the fun i guess trying out new things.
another option would be the complete opposite, to press a slower fuel grain for the first increment and this would act as a eroding/ consumable nozzle aiding lift. indeed the nozzle-less rockets are very good as they are , im just tweaking.any thoughts theories would be greatly appreciated

Edited by chris m, 20 October 2008 - 03:15 PM.