Amazingly no fatalities or injuries - Brandon managed to design and build a contraption that actually worked … well at least rotated without shrapnel or the table dancing around the floor like a Bronco due to balance issues. The Blast Shields made up of overturned worked tables surrounding the test runs add a true sense of adventure to the tests.
The onsite “stress engineer” doing calculations with a felt pen on metal gave prognostications an astrologer would envy and so many qualified “if’s”, “it shouldn’t” and “probably won’t” that he sounded like a politician. I guess he was somewhat vindicated by the test results.
But a must say: well done hack and great first attempt to build on. Thanks for the show!
Anyone have experience using split taper bushings? I’m assuming using it as hub to mount an 18" diameter impeller would be fine, the split should just retain it on the shaft and not cause any weakness right? The pdf applications shows these typically being used to mount pulleys, but the load I’m putting on this as a hub will be ~4 inches out away from the flange instead of being in line with it.
I was thinking of milling a hub for impeller v2, but I would have to get some pipe, build a jig to hold it perpendicular, get some flat stock to use for face, weld it together, face it off in lathe, broach keyway, drill mounting holes, when instead I could just buy this for $11.50. All the gokart wheel hubs on amazon I could find are for 1" axles, and I need 3/4" if I’m going to mount it to a predator engine.
We use them all the time in the HVAC industry. You should be fine. I have seen them used on all sorts of different configurations. The key is everything must be balanced, if not it will amplify the vibration.
How long a piece of metal do you need? I may have some round stock from the Treasure Palace that may be usable or close in diameter. These aren’t mild steel so they’d be good. With right cutter insert you could turn to exact size needed.
Will check when I get home, all my “stock” is longer than that. Diameter is issue. If I find anything when I get home, I’ll bring to space and put on your pallet. We’ll need to send Fred a photo and how his generosity is being used to build madness!
Brandon, there is a .750" x approximately 18" piece of round bar stock (looks like some form of stainless, maybe chrome covered hardened steel) sitting with your Fan of Death.
The HF Predator engine went on sale again ($99) so I picked one up, the first step may be welding together an exhaust extension to relocate the stock muffler, which extends 1.5" into the plane where the blower housing will need to sit.
Also does anyone want a cheap 22" push mower? It will be going to the donation shelf after I replace the pull coord, (runs great, only reassembled once)
[quote=“Brandon_Green, post:28, topic:7174, full:true”]
The HF Predator engine went on sale again ($99) so I picked one up, the first step may be welding together an exhaust extension to relocate the stock muffler, which extends 1.5" into the plane where the blower housing will need to sit.[/quote]
Bears a resemblance to the engine on the folks’ old chipper-shredder that I sort of absconded with. It can munch up 2" branches with surprising speed.
I recommend a metal impeller. I’ve got a feeling that even a quality plywood disc would be chancing things.
That calls for a jig of some sort. But maybe it’s something you could do on the bridgeport with one of the rotary vices they have and some creative supports to get around the inevitable wobble that sheet metal will produce? Would also allow for some reasonably precise hole placement.
Yes you can. You coat the metal with layout die/ Use a scribe and compass to layout your pattern (perhaps even cutting a pattern out of thin wood or plastic on the laser cutter). You then band saw just outside the lines and use a file to finish it off. Shouldn’t be more then two or three hours work.
I cut my shell sorter plate out of plastic on my table saw, round of course. So you could make a jig to slide on the dovetail of the bandsaw with your radius of the circle you need.
Turns out that bar is ~25 thousandths over 3/4, and turning hardened steel on the lathe is very difficult, was able to do it without breaking any inserts with some help, but took awhile, and only having 1.5" sticking out from chuck still resulted in it deflecting ~5 thousandths at the end while cutting (should have put in tail stock support but didn’t think of that at first).
Considering how acute the accurateness and tolerance bands that the rest this project is being built to … 025" seems like high tolerance.
If you were able to deflect a hardened bar .005" with only 1.5" inches of unsupported stock I’d guess you might have been a tad aggressive in the cut feed and speed. You did use a cutting tool and not just the tool holder - which has been done in the past.
Anyway, sounds like you got it done - of course you could have chosen a piece form the other donations!
Was using the one remaining non chipped carbide insert I could find, taking off 5 thousandths per pass, I think it was ~1000 rpm w/ power feed at S3 (either .014 or .003 inches/rev, not sure which picture applies). The rod is now a very tight press fit on the hub I got. What would the best approach be when trying to reduce diameter of a shaft that I assume is something like: http://www.amazon.com/Thomson-QS-12-Diameter-Rockwell/dp/B00TSGMJTC ?
