moonshot Posted February 15, 2007 Posted February 15, 2007 I ram my rocket motors on the flat part of a medium sized bench vise. The vise makes a very stable and massive platform for ramming. I can also sit on a comfortable high stool. helps when your as old as I am Your tooling looks great but the spindle seems a bit short for core burners, but the proof is in the performance and your rockets work very well. All in all a very good presentation!
pudidotdk Posted February 15, 2007 Posted February 15, 2007 Yeah, the spindle is short, but the aluminium is somewhat soft, so it's not very solid. The other day I say that the spindle was a little bended so I took the A-rammer over the spindle and corrected it as much as I could. Can the spindle be made out of stainless steel without chance of sparks?
moonshot Posted February 15, 2007 Posted February 15, 2007 I have not made spindles from stainless steel. I build my tooling from brass because it is so easy to machine and will not spark. I built a spindle from aluminum for 1/2" ID motors and it worked good for about 6 motors then for some reason it started breaking the nozzles when I twisted it out. I think it was too soft of an alloy. Try brass. I find it is more durable than aluminum.
Mumbles Posted February 15, 2007 Posted February 15, 2007 Most commercial tooling is made from stainless steel. I think the rammers are Aluminum as to prevent any sparking.
Aquarius Posted February 15, 2007 Posted February 15, 2007 You can make spindle out of stainless steel, I have made several. The arhguing point is mainly sparks, but if you use aluminum or brass rammers you avoid that problem. My 2 cents on steel is to go for an alloy named "Leadloy", it has a small percentage of lead, wich makes it very easy to work with. As for aluminum spindles, they bend easy and if you bottom out with your rammer, they will compact and bulge. You still have to ground your equipment, remember that!
Frozentech Posted February 15, 2007 Posted February 15, 2007 As for aluminum spindles, they bend easy and if you bottom out with your rammer, they will compact and bulge. No matter what your rammer is made of, if you bottom it out while ramming, BP can be compressed at a high enough pressure at a small contact point to ignite. This has happened to to several people, with no steel involved. Some experienced rocket builders also claim it can happen if BP get compacted inside the drift of the rammer, then comes *close* to bottoming out, the fuel will be intensely compacted to the point of ignition up inside the drift. Mark all rammers to avoid bottoming out !
oriansbelt Posted February 16, 2007 Posted February 16, 2007 Has any one tryed white cast iron spindles? White cast iron is very wear resistant and hard so it might make a good spindle or maluable cast iron which is about the same thing just not as hard. The Leadloy alloy which was mentioned is probably a grade 12##(I'm not sure of the numbers for that one specifically) and it is made for machining but is not not hard or strong at all for a steel. @ewestOh, I wasn't aware of the sparking effect, I was just suggesting it on durability. Though if u used a plastic rammer it wouldn't be a problem.
ewest Posted February 16, 2007 Posted February 16, 2007 Doesn't cast iron spark if you hit it with another metal? It's not a good idea to have tooling made from materials that will spark when you're loading black powder in them. That's why they're made from Aluminum, Brass, Stainless Steel, Plastic, or Wood. I like Stainless Steel or Brass Spindles with Aluminum rammers myself.
FrankRizzo Posted February 17, 2007 Posted February 17, 2007 Here's a tip for anyone who has bent their spindle and has access to a lathe (if you're in college, check the mechanical engineering dept). Chuck the spindle into the lathe, and then put a dead center in the tailstock and move it down the bed so that the point is as close to the spindle tip as possible. Now rotate the chuck by hand, noting the tip of the spindle's offset from the point on the dead center. Use a rubber mallet to tap on the spindle while turning the chuck by hand until the tip of the spindle and the tip of the dead center are as close to inline as possible. It doesn’t have to be perfect, but you should be able to get close enough to make your tooling work again. I build a press based on Dan William's design a few years ago and didn't include the blast shield on the front. Bad idea if only from the safety aspect. I didn't understand that the thick Plexiglas also made the press rigid to side stresses, so I bent my spindles quite a few times when the threaded rod on the sides would bend toward or away from me from the thrust load during a pressing operation. It would usually be worse when finishing a rocket, where the tooling wasn't centered by the tube and could press sideways against the tubing wall.
moonshot Posted February 18, 2007 Posted February 18, 2007 here is a pic of my homemade star pump and star gun.http://i107.photobucket.com/albums/m314/di.../Picture067.jpg also some of the aluminum/meal BP stars I just pumped. http://i107.photobucket.com/albums/m314/di.../Picture068.jpghttp://i107.photobucket.com/albums/m314/di.../Picture069.jpghttp://i107.photobucket.com/albums/m314/di.../Picture070.jpghttp://i107.photobucket.com/albums/m314/di.../Picture071.jpghttp://i107.photobucket.com/albums/m314/di.../Picture072.jpg The star gun was easy to make. I just welded a bolt into one end of a piece of steel pipe turned it down on the lathe and drilled a hole in a piece of aluminum to make the base. then drilled a fuse hole in the side just above the end of the bolt. I made the pump with an over sized knob on the end so I can tap it with a mallet to get good compaction on my stars. The aluminum /BP stars work great, nice long white spark tails and burn completely.
moonshot Posted February 19, 2007 Posted February 19, 2007 Here is a pic of the latest spindle I machined. It's not quite done I still have to trim it to fit the 1/2" hole for the base.http://i107.photobucket.com/albums/m314/di..._07/Picture.jpg I made this one to ram 5/8" ID 5" long rocket motors to lift a 2" canister shell. I have an idea to build the shell onto the end of the motor. The spindle is aluminum so I should be able to get 8-10 motors off it. I will try to post pics of the build process and test flight. First off, sorry about the double post. Once again my ignorance of forum etiquette rears its ugly head . I just finished the rammers to go along with the spindle in the previous photo. The set turned out pretty good. All aluminum but I will do another spindle in brass. http://i107.photobucket.com/albums/m314/di.../Picture077.jpghttp://i107.photobucket.com/albums/m314/di.../Picture076.jpghttp://i107.photobucket.com/albums/m314/di.../Picture075.jpg The final tube size ended up to be 13/16"(15mm) ID by 5"(130mm)long. I may need to open the nozzle ID up just a bit. Only way to find out is to ram one up and test it. glad I just grained up 200 grams of propellant because these motors are going to take a bunch! Hey Al you might want to move this to the rocketry forum.
jacob Posted January 9, 2008 Posted January 9, 2008 BUMP. I thought i would post my new motorized charcoal grinder. i got sick and tired of wearing myself out grinding through a bag of charcoal by hand, but i didn't want to spend $50+ on a purpose built v-belt wheel grinder so i went with plan b, slap one together out of junk i already had lying around.since a picture says a thousand words i'll let them to the talking. let me know what you think.
Mumbles Posted January 9, 2008 Posted January 9, 2008 Looks very good. I've actually been on the lookout for a meat grinder lately. The blender is getting tedious for crushing the harder Cowboy brand charcoal. Crushing the willow would be nice too.
oskarchem Posted January 9, 2008 Posted January 9, 2008 Hey, woulden't just ball milling the charcoal be easier? I mean making the charcoal like coarse, by hammering it down in a bag then putting the coarse stuff in a ball mill and let it mill for like 8-9h?
qwezxc12 Posted January 9, 2008 Posted January 9, 2008 Dude, that's cool. Can't wait to hear how it works! Grinding charcoal is one of the dirtiest, tedious jobs in amateur pyro...I hate it. The Alder I use for lift grinds up fairly easy, but the CowBoy lump hardwood that is the mainstay of my charcoal sucks to process. I have throught on how to mate a spare windshield wiper motor assembly (high-torque and already geared down) to my grinder to power it. You've given me a little more motivation!
Frozentech Posted January 9, 2008 Posted January 9, 2008 Hey, woulden't just ball milling the charcoal be easier? I mean making the charcoal like coarse, by hammering it down in a bag then putting the coarse stuff in a ball mill and let it mill for like 8-9h? That works OK for 1-2 lb, but not so fun doing 25 lb bags by hand. This way he can screen out different mesh C for compositions, in a reasonable time with less mess, and save the ball milling time.
bmarley5780 Posted January 9, 2008 Posted January 9, 2008 Wow- More people the I thought use the Cowboy! Jacob- very good idea on hookin a motor to a meat grinder! Lazy but AWSOME non-the-less. I used a bucket and the end of a sledge hammer to crush up the charcoal before the blender...
jacob Posted January 9, 2008 Posted January 9, 2008 Mumbles, yea it's pretty tough, actually Cowboy brand is what i just ran through it, worked just fine. the weakest spot is the green coupling between the grinder and gearbox, the original one was made out of Acrylic but was too brittle and snaped, this one is made of Polyethylene and seems to hold up fine. if you want there is a junk store near me that has some meat grinders, i could probably get one for $10-$20 dollars plus shipping. oskarchem, This can process much more in much less time then my ballmill, granted i still have to mill it down to airfloat but with my ballmill it only takes me about 30 minutes to go from corse to airfloat, whereas it might take hours for my mill to go from lump to airfloat. so this still saves time and is easier than bag milling. EDIT. qwezxc, a windshield wiper motor, what a great idea, unfortunately it's still almost as messy as before, i'll try to get pics later of how i made the grinder to motor coupling, i think you'l be interested. bmarley, lazyness is the mother of invention i destroyed a blender in about 3 seconds trying to crush Potassium Chloride chunks, it was old though that may have had something to do with it's weakness. Thanks for the replies everyone, i'll try to get a video of it in action.
TheSidewinder Posted January 9, 2008 Posted January 9, 2008 Very nice work on mechanizing a boring and tedious job, jacob! I recently acquired a grinder attachment for my heavy-duty mixer, and that's gonna be put to good use this Summer. I'll also endorse Cowboy lump charcoal. I have a bag of "Cowboy-generic" I got at a local supermarket on a closeout sale. They called it "Gourmet Lumpwood Charcoal". Go figure... probably trying to justify a higher price, but it's the same base material as Cowboy brand. Mostly sticks about 1-2 feet long, 2-3 inch diameter or so. 100% Hardwood, snaps clean and is shiny black to the center. It was only $6 for 10 pounds, as well. Not sure why they wanted to stop carrying it. Maybe it was actually lousy for grilling steaks, I dunno, but figured it was worth a try instead of buying more (Hardwood) airfloat. And it worked great! Between that and the order I placed last year for Willow and Yellow Pine charcoal, I'm set for a decade.
Mumbles Posted January 9, 2008 Posted January 9, 2008 I recently picked up some willow for making lift and such. Batch in the mill as we speak. However, I absolutly love the cowboy for burst, and ball milled stars. The commercial stuff just isn't good enough for fast burning stars. Works just fine in glitters, and other unmilled stars though.
qwezxc12 Posted January 10, 2008 Posted January 10, 2008 snip...qwezxc, a windshield wiper motor, what a great idea, unfortunately it's still almost as messy as before, i'll try to get pics later of how i made the grinder to motor coupling, i think you'l be interested.Please do. I've looked at my grinder and it uses a square shaft end that the handle mates to. The handle is retained by a wing nut. I should be able to use a piece of steel square tubing stock as a drive-shaft, by grinding flats into the threaded portion of the grinder and using a set-screw. Wiper motor assemblies are great low speed, hi-torque motors (and they're cheap at the scrap yard) My star roller runs on an ATX computer PS and a wiper motor...it's a very flexible system to tune speedwise as the motor has both high and low speed wiring, and the power supply HDD harness has +12 and +5VDC with a ground so you can have 12, 7 or 5VDC to run the motor. I think I'm currently running 12volts and using the low speed motor hook-up. Throw a SPST toggle on the 20 pin Molex MB connector between the PS_ON and COM and you're all set for turning it on / off. How many people can say they have an BMW star roller?
asilentbob Posted January 10, 2008 Posted January 10, 2008 I use cowboy brand lump charcoal too... Love the stuff... have been looking for something like this to pre-grind the lumps down for a while. Great work!
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