I Didn't Like the Pulleys on My Drill Press

[Crusty]

So I decided to make new ones, casting them in aluminum and then machining to final form.

So first I needed a furnace to melt aluminum. I made one from a Homeless Depot bucket, some Kaowool and a refractory coating. I needed a propane burner too so I made one from steel pipe and other scrap steel with a hair dryer for a blower. I used the handle valve from a propane torch to control the gas into my furnace and a waste gate on the feed tube controls the air into the burner.

So then I needed things for casting. I bought a crucible then I made lifting tongs and a pouring shank for it, as well as a pair of general grabbing tongs, a stir rod and a dross remover, along with a mold for ingots.

What else? I need a flask to mold the parts in so I made one.

I needed greensand for molding so I sifted and mixed up two tubs of facing and bulk greensand plus made a screen sifter.

OK then, I intended to use the lost foam process so I needed a hot wire cutter to make the forms. I made this one using a 16 banjo string which seems about the right resistance for the 12v, 2 amp battery charger.

What else? I needed some aluminum to cast so I bought a Kia engine from a junkyard, disassembled it and then broke it down into chunks which would fit into the crucible.

And the spirit sayeth unto me "Goest thou forth and cast thine ingots upon the mold, and so I did for the most part though I slipped on some lion scat and struggled to finish a weak sixth.

Those are 5lb ingots and I got 11 of them from that engine. The aluminum seems to cast well.

So finally I was ready to try to make some castings. Here's a couple after rough machining and one straight out of the mold. It took a couple of attempts and the lost foam process left pretty rough surfaces so I'll likely use the traditional greensand casting method in the future, though making foam forms is a time saver over wooden ones.

And here are my pulleys with the external machining done.

And here they are fitted to my DP finally.

[DIYer]

Thanks Crusty! We've added your Furnace to our Forging and Casting category,
as well as to your builder page: Crusty's Homemade Tools. Your receipt:

Furnace by Crusty

tags: furnace

[DIYer]

Thanks Crusty! We've added your Casting Tools to our Forging and Casting category,
as well as to your builder page: Crusty's Homemade Tools. Your receipt:

Casting Tools by Crusty

tags: tongs, crucible

[DIYer]

Thanks Crusty! We've added your Drill Press Pulleys to our Drilling and Drill Presses category,
as well as to your builder page: Crusty's Homemade Tools. Your receipt:

Drill Press Pulleys by Crusty

tags: pulley, drill press

[trigger]

You do know Mc Master delivers ,saves you slipping in the Lion scat especially if it might still be lurking in the yard somewhere.I also recommend Chevy or Ford to keep it Made in the USA...;-)

[metric_taper]

The last time I priced step V-belt pulleys, there was shock. So what was wrong with the original ones on the drill press?

[Crusty]

Fantastic plastic slippers and replacement belts were unavailable so I converted to higher torque standard 3VX series belts on the new pulleys.

[metric_taper]

Fantastic plastic slippers and replacement belts were unavailable so I converted to higher torque standard 3VX series belts on the new pulleys.

I compliment you on all the tools built to do a casting, the cope and drag, the hot wire cutter. Did you make a crucible from steel pipe?
I see you put the aluminum block on charcoal, was this to burn the oil film off? I didn't see how you would catch the melt into the ingot form you showed.
Was the foam that white styrofoam 3/4" sheets you get from the material supply?
That took some doing to hog out the V-grooves with a form tool. Takes lots of time as I know you can't grab the casting in a way that just lets the machine whittle away the unwanted. I don't see the chatter in any of the surface finish in the grooves.
Sorry for so many questions....

[Crusty]

The shocking prices for step pulleys is the primary factor which drove this project.

I bought a clay graphite crucible since I intend to make more castings and steel crucibles don't last very long. The PMC brand seems to be OK. Buy your crucible first and then build the furnace around that crucible so that it all fits when you're done. Two inches of Kaowool is plenty. Closer walls to the crucible improves the heating of the furnace but there has to be room enough to get the lifting tongs in there.

I highly recommend that you build a forced air burner rather than a naturally aspirated one because it can be tough to get a natural one sized to draw correctly. A hair dryer with a blower setting provides more than enough air and you can discharge the excess air through a waste gate, plus the propane orifice isn't a critical dimension on a forced air burner.

I was trying to anneal the aluminum block so that I could bust it up with a sledge. It didn't get hot enough and only worked for the lowest section but I thought the pic was cool. The fire no doubt helped but I still got a lot of dross when I cast the engine into ingots, but $40 for 55 lbs of ready to cast aluminum is still a good deal to me.

The form is just a tray made from a piece of angle iron with ends welded on and I pour the ingots from the crucible. The open corner points upwards and it produces long triangular ingots which can be readily cut into crucible sized pieces on the bandsaw.

I used the extruded insulating foam from Homeless Depot rather than typical expanded polystyrene foam. Half inch thick and spray adhesive to join the pieces.

I plunged with a cutoff tool into the middle of each groove to the proper depth and then cut tapers on either side using the cutoff tool again and the compound set to the correct half angle for each side. Didn't take long and left nice surfaces. The central plunge provides relief so the taper cuts go easily and quick. Form tools can be a pain to use on a small lathe. Touch up the tool cutting edge often because it deforms in the process.

I'm going to make two of the three pulleys over again because with my limited fixturing they didn't turn out concentric enough for me (I want my DP quiet and smooth). I've ordered a couple of mandrels with expanding collets to turn the new pulleys on between centers so I can guarantee concentricity. Doing it like that I'll be able to machine all important surfaces without changing my fixturing so that the part stays centered.

If you don't have to turn the part around then mounting a central hole drilled through the rough part onto a bolt chucked up with the head behind the jaws and a nut forcing the part into the chuck can work, but the bolt ought to have a divot on the end for the live center in the tailstock so that it's exactly on center and the central hole should be a close fit to the bolt shank (mine wasn't close enough).

It's worthwhile to make all this stuff because it's a joy to unmold a pour and see a rough casting which can be made into something useful, and melting metal is flat out fun. Buy a pair of aluminized leggings and wear good boots which you can get off quickly just in case.

[Saltfever]

Very nice. I can't see from the finish-machined pics; how was the porosity? You mentioned skimming dross/slag but did you do any out gassing before the pour? If so what did you use?