Chain Drive rear spool

[Doug Heim]

That's what Ill check on. I have 15mm in the shelf. I use them for the PIRCV Sprockets.

Don't even bother with the button heads. I could not find those at all. I ended up drilling out the M10 X 1.25's to 7/16"-20 (pitch and diameter close enough to drill out and re tap) and the 7/16"-20 button heads are even more expensive. About $6.50 ea. But hey go for it. If you can find them cheaper Ill buy some. I have both the 7/16"-20 BHSCS and M10X1.25 FHSCS. I have 48 of ea. and you can do the math to how much I have invested in enough hardware to fit in you hand. Its ridiculous!

When Rick and I were designing and building for his idea of the rear I used in my Piranha I had sourced up a 5/16"-24 LH flat head. They were $15 ea! We bought 3. 3 bolts for $45. That's whats ridiculous!

Oh and yes I am aware that most flat heads run out. You see that in allot of hardware sourced from overseas. I too have had no problems though. I also use a locating diameter in the hub to the sprocket's bore.

[Rick S.]

We're c'sinking the head flush in 3/8 material, so 5mm thread engagement wouldn't cut it. Let me know what you find out.

[Doug Heim]

I can get them. Oh and I have 20mm on the shelf. I lied!

[Rick S.]

I need 8 of M10x1.25 x 25mm long. The 20mm would only give me 10mm thread engagement. I like to have a minimum of 1 1/2 x dia. thread engagement.
How much and is paypal OK?

[Admin]

I havent found crap either, i did locate the 7/16 for 8.00 each tho, no call back on the 10m..

[Rick S.]

I tried Metrics Unlimited today with no luck.
They need to change their name.

[Admin]

Your skilled enuff, just make them yourself...

[Doug Heim]

I was going to make them but oped not to.

Paypal is fine.
$5 ea. and $5 for shipping.
I can get 30mm as well.
Just PM me or place in the comments in Paypal and Ill order them tomorrow.

[dsrace]

Here are the 428 blanks. I'll post more pics of these when complete.
I need to face one side down on each and c'sink some holes.
The 1/2" ring spacer will be used as is.
The small washer has the prototyped spline to be checked against the RC51's spline shaft.
I'll tweak the dxf if needed and run the small sprockets next.

just out of curiosity, why didn't you use an aluminum spacer between the sprockets?  I have seen the short chains get got and melt the o-rings between them but what is more interesting is that the heat actually came from the sprockets. coming off the dunes this rail has some cool down time ( not a bunch ) low rpm and low speed. never saw any problems at the dunes but in the dirt, when it runs 90 mph - 110 mph in 2 miles runs for a total of 8 back to back then skids to a stop, shut down with little to no cool down period the heat from the sprockets is absorbed and cooks the o-rings. you can even see the contact patch on the chain ( from the heat ). I was just wondering if it would be better to make the spacer out of aluminum with cooling teeth or fins    ( similar to a flywheel )?

[avendlerdp]

I like that idea but it's not happening on this version of the setup due to my need to get this stuff done soon.  I have a race event coming up and have to test a bit before hand so time it of the essence. 

The whole idea here anyway is cut heat down by using these smaller pitch chains.  The shorted the pitch, the slower the chain speed, and the fewer times the links bend for each tire revolution.  Also, the smaller chains have a greater surface area to volume ratio and thus cool better...  I hope.

[Rick S.]

We were trying to keep the cost down. Aluminum was considered.
I also thought about tapping the spacer and using 4 flat head screws in each sprocket.
But tapped holes and aluminum = higher cost.
Here is the front sprocket so far.

[Doug Heim]

Is it just me or do the splines look a little goofy on the sprocket on the right? Like their tilted. Is this done for a reason or is it just an illusion?

metric Flat M10X 1.25 on the way! Man I must have a good hardware source!

[avendlerdp]

I saw that too Doug.  I'm sure there's a good explanation.  It seems unlikely that Rick would have not noticed that!

[Rick S.]

On very thick pieces you get noticeable blowout on the bottom side with a waterjet.
This is why this needed to be two piece. The more precision 3/8 half is against the motor.  The 3/4 gets tig welded to the 3/8 using a jig to keep the teeth and splines in line. 
I placed the sprocket teeth on the entry side of the 3/4 piece because the tooth accuracy is more important than the splines. Even with the funny blowout the 3/4 piece fits nice on the splines with very little chatter. No more chatter than was there on the stock sprocket. After heat treat it will be even tighter. I probably could have just splined one half, (since it does get welded) but I thought it best to capture splines in both pieces.

[Doug Heim]

sounds good enough to me... What is the material and what is it to be heat treated to (rockwell)? I may have you look into doing some splining for me on the H2O jet in the future.