Supercharger pulley

[Tacoclaw]

Hey, everyone, I've been messing around for about a month trying to get a blower drive pulley made for my truck. I had the equipment to make it, just not the balls, and after getting no calls back after that much time I just went for it. It's all done but the grooves, I've failed three times at grinding an acceptable HSS cutter so I'm having them done by a pro. Even I know my limits, especially when it's the last step.

Once finished I'll turn some more weight off of it and drill some lightening holes in it.


*Disclaimer*
Your results may vary, the measurements are for my '90 W250 with electric fans and a stock balancer. It is unknown if you can run the mechanical fan with this as I have none. My idler mount is #3911660 and the center hole is a slip fit over the fan threads. If you opened it up to clear the hex of the fan it may work.

[oldestof11]

Looking good Levi

[Tacoclaw]

Thanks, Jon.

It'll be nice to get this done, I haven't cobbled any bracing together to mount something on since my twins.


Another note, the ribs on a serpentine belt are supposedly 40* but there's a radius at the bottom of each groove. I doubt it's important but just in case it is it's best to have the blower pulley there to copy the profile off of.

[WUnderwood]

well done!

[Lostnwalmart]

well that went from ewwww to ohhhhh pretty dang fast

[Tacoclaw]

Thanks, guys.

No doubt, Lost, I scoured our junk pile for anything resembling 1-1/2" plate or 7.5" bar. Nothing...

I finally found this 2" thick plate and attacked it with the torch. Torching isn't my strong suit, so I gave myself plenty of room to mess up and that's what I had to start with.


It did end up cutting nicely, I've only got about 20 hours in it spread across 4 afternoons.



And 1/2 of a 55 gallon drum full of metal shavings.

:edit:
I also intend to drill and tap the holes in the fan idler to something a little stouter, I'm not sure I trust 6 M6 bolts to handle driving a blower.

[Mark Nixon]

Originally Posted by Tacoclaw

...I haven't cobbled any bracing together to mount something on...

Such decent work, why add the word "cobble" into the mix?

I can see those belt grooves being a real PITA for even a good machinist.

Mark.

[mathews8pt]

Looking good man!

[Tacoclaw]

Thanks again, everyone!


Mark, this pulley does look good, I'm actually pretty proud of how it's turned out so far, but I can assure you that any bracing I make to support the blower will best be labeled as "cobbled".

Here's my practice run on the grooves, they started out nicely but my cutter caught an edge and took a chip out of the tip. That plus me not relieving quite enough off the sides and ruined it after the 4th plunge. Once it messed up I simply couldn't regrind it quite the same.

[Tacoclaw]

Back from the shop, dude did good. I told him to favor it towards the front of the pulley to give me as much clearance as possible.



Now then, are there any math gurus here that have a formula to tell you how many 1 5/32 holes you can drill around a circle with an OD of 6.250 and an ID of 3.804?

I know it'll clear each edge by about .033 but I'm wondering how many I can fit around it side by side. I can easily whip out 4, 8, or even 16 but any numbers not divisible by four will take some extra mathing, which I'm no good at...

[Tacoclaw]

Sooo, I found the circumference of the halfway diameter between them; diameter is 5.034 circumference is 15.806, then divided the circumference by 1.156, which is the diameter of the drill bit. That comes up to 13.6, so I could fit a maximum of 13 holes in the space given, right?


Anybody possibly double check that for me...?

[Tate]

The bolt circle diameter would be 5.027". If you figure out the chordal distance on that given diameter for 13 holes, its 1.168" to center of each hole. If hole diameter is 1.156, that only leaves 0.012" material between holes. That is 0.645" to the OD and 1.165 to the ID.

[Tacoclaw]

Fine, ya bastards, I'll figure it out myself.

I rarely consider myself spoiled in terms of machining equipment, it's all well-used manual stuff, but our lathe has an Aloris toolpost that I consider a complete luxury. I'm now spoiled completely in another way, I used our Bridgeport indexing table for the first time tonight. Holy ****, that's so much better than scribing intersecting lines and center-punching them.

Here's the goods, got it down to 6lbs according to the bathroom scale, I may do some more mathing and see if I can get some smaller holes in the spaces around the big ones.

[Tacoclaw]

HA!

Thanks, Tate, guess I was typing mine out as you posted that.

[chevydiesellly]

Subd

[Mark Nixon]

Personally, and not that my opinion matters a whit, but I think you're probably as light on that as is practical.
Much more might not be worth the effort and diminish the strength.

Why use steel and not high density/alloyed aluminum?

Mark.

[Tacoclaw]

I just don't have access to free, giant chunks of aluminum, it took me a couple days to dig up a chunk of steel big enough to make this thing. It woulda been much quicker hacking this thing out of aluminum, that's for sure.

[iker42]

This is freaking awesome to see. Kind of reminds me of that guy who was doing his own clutch and a bunch of morons got their panties all in a bunch because "he was copying people"

This is perfect, someone who wants to make something instead of paying an arm an a leg for it.

[Headcase98002]

Looks good, can't wait to see is all put together.

[Tacoclaw]

Thanks guys.