Run in stand/dyno build.

[Terry Keeley]

Got the wheel roughed out, left 0.030" for clean up. The Boss said to leave it in the garage a coupla days to "settle in" so the scatter shield is next...

 

[Brad Christy]

Terry,

Is that 4140 PHT or annealed? Either way, I wouldn't expect too much stress in the slug.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[Terry Keeley]

Terry,

Is that 4140 PHT or annealed? Either way, I wouldn't expect too much stress in the slug.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

4140 HT (30 Rc). Ya, don't expect it to move much but it can't hurt...

 

[Steve White]

Do you have a design for the scatter shield? I did some hillbilly math waiting for breakfast yesterday at a local cafe and could be if it fragged @ 26K the velocity of fragments could be approaching the muzzle velocity of a 45. Back in the day bench running ST .15's on the pipe at 28-30K and reaching around behind them to tune makes me queasy today.

Great project BTW, thanks for sharing it.

 

[Terry Keeley]

Yup, just ran a 67 to 28K a couple times with the fan, it's gonna be a little intimidating running the wheel there at least at first.

Shroud is gonna be 3/4" wall DOM tubing, I'll leave the ends open:

 

[Steve White]

^^^ When that thing reaches 88 MPH you're gonna see some serious schitt...

 

[Terry Keeley]

^^^ When that thing reaches 88 MPH you're gonna see some serious schitt...

Care to explain?

 

[Steve White]

Care to explain?

Doc Brown quote from the movie Back to the Future - "When this baby hits 88 miles per hour you're going to see some serious schitt".

Back To The Future - 1985 - Delorean Time Machine 88 MPH [HD] - YouTube

 

[Mike Bontoft]

Probably missed it somewhere here but what is the weight of the wheel?

 

[Terry Keeley]

Probably missed it somewhere here but what is the weight of the wheel?

About 33 lbs.

Should finish it up this weekend and send it out Mon. for balancing...

 

[Marty Davis]

Do you have a design for the scatter shield? I did some hillbilly math waiting for breakfast yesterday at a local cafe and could be if it fragged @ 26K the velocity of fragments could be approaching the muzzle velocity of a 45. Back in the day bench running ST .15's on the pipe at 28-30K and reaching around behind them to tune makes me queasy today.

Great project BTW, thanks for sharing it.

Terry:

This is a VERY dangerous piece if it gets loose. Be sure you have enough of a shaft to support it if the bearings fail. It can kill you if it gets away.

Marty

 

[LohringMiller]

We used a similar steel to Terry's that was also heat treated. We ran it up to 25,000 rpm without problems. However, we did throw a sensing magnet. I think it went through the dry wall in Mike's shop. Don't put anything valuable beside the dyno. We didn't have a scatter shield. I would expect to need a Kevlar blanket like dragsters use over transmissions. I still wouldn't want to be very close if anything let go. We siezed engines with various amounts of destruction, but the flywheel was unscathed.

My brake dyno's resistance was varied by moving the magnets into the space between the disks. If you look at the pictures you can see the servo I used for this.

Lohring Miller

 

[Terry Keeley]

Terry:

This is a VERY dangerous piece if it gets loose. Be sure you have enough of a shaft to support it if the bearings fail. It can kill you if it gets away.

Marty

Thanks, I hear ya loud and clear.

I'm hoping I've done my homework: Run in stand/dyno build. For 1/4" radius the safety factor is about 3, I went 1/2".

The 3/4" wall shield will be held to the base plate with two 4" X 1" steel pillars and 4 X 3/8" plus 9 X 5/16" Holo chrome SHCS. If the wheel does get loose that shud contain it, or at least slow it down enough so I can exit stage left.

I explained to a very competent balancing shop here that I wanted to spin this to 30K and they didn't bat an eye but "upgraded" my suggested G2.5 to G1.0 balancing.

Of course I'll bring it up to max speed in steps checking for harmonics etc. I'm gonna bet these 67's won't make much useful HP beyond 25K...

 

[RaceMechaniX]

The finer they can balance the better. G1.0 should not be too hard to hit with that much mass.

 

[Terry Keeley]

 

[Terry Keeley]

Think this would stop a 45?

 

[Terry Keeley]

Got the wheel finished, it'll go for balancing this week.

Getting the right bearing fit on something this big took some head scratchin':

Finished it between centers for accuracy.

 

[Brad Christy]

Terry,

Dang, Terry..... That's starting to look like a real shop!

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[Ricky Neal]

Terry, Thanks for sharing all this information. It is very much appreciated. Can you tell me what tolerances you settled on for the bearing fits (I am not an engineer and while I have a full machine shop I rely on shared information when it comes to machining things like this)

 

[Terry Keeley]

Terry, Thanks for sharing all this information. It is very much appreciated. Can you tell me what tolerances you settled on for the bearing fits (I am not an engineer and while I have a full machine shop I rely on shared information when it comes to machining things like this)

There's lot's of info around on bearing fits but I found this from NTN pretty straight forward:

https://www.ntnglobal.com/en/products/catalog/pdf/2203E_a07.pdf
I went on the tight side of J6/7 for the housing and loose for the shaft. For my 6005's that meant a coupla tenths press for the housing and right on size for the shaft.

Just to be sure I checked the bearings and one of them had a bore two tenths over nominal! Tolerance for ABEC 3 is +0/-10 microns (4 tenths). Good thing I checked.

I wish the crank fits were this good from the manufacturers, my CMB's are usually a half thou or so loose causing them to slip and burn up at higher revs.