I am glad to hear you like the gage. I'd also like to give you
for your creativity on using the sandpaper and file in conjunction with the wheel shaver.Pinewood Derby Car Mini-Lathe
Re: Pinewood Derby Car Mini-Lathe
Speedster,
I am glad to hear you like the gage. I'd also like to give you for your creativity on using the sandpaper and file in conjunction with the wheel shaver.
I am glad to hear you like the gage. I'd also like to give you
for your creativity on using the sandpaper and file in conjunction with the wheel shaver.
Re: Pinewood Derby Car Mini-Lathe
This is great!
I always wondered what would be possible with the Derby Worx Pro Wheel Shaver.
Can it really bring the wheel to within .001" of round?
When I got mine I realized that sharpening the blade on a sharpening stone greatly improved it's performance.
Knotty,
That tool you made looks well designed, not just fabricated.
The price seems too good!
Nice work!
I always wondered what would be possible with the Derby Worx Pro Wheel Shaver.
Can it really bring the wheel to within .001" of round?
When I got mine I realized that sharpening the blade on a sharpening stone greatly improved it's performance.
Knotty,
That tool you made looks well designed, not just fabricated.
The price seems too good!
Nice work!
Re: Pinewood Derby Car Mini-Lathe
What if the bore is off .001? I would never be able to improve the wheel past that. I have since tested wheels from various vendors. If you are buying wheels I urge you to test them.
Re: Pinewood Derby Car Mini-Lathe
Speedster,
Bore condition could certainly play a role in the quality of the wheel.
Measuring and understanding the bore and it's condition and or form could prove quite difficult with it's small size. You can visually see defects in some of them, like depressions. Are those helpful or hurtful - I have no idea. Some say that is where using single grooved axles helps, as it eliminates the amount of area where defect could be present in your riding contact area and that is a very logical theory.
My gage does not provide the "real" runout of the wheel, it provides a real life usage conditions test that also picks up other cylindrical form problems with the wheel if you are using the wide tip. But hey, you have to call it something and that was close enough for this application.
To truly measure runout, you would have to measure it to the axis (theoretical centerline) of the bore. That is not really a practical option in our case. Even if we could do that, we would want Total Runout, not just Runout - which is a different measurement. Also, you would not see any form error in your bore show up like you may or may not see with my gage. The idea was to keep it simple and practical to the application with a quick go-nogo check.
If you're board, here is a link that might help with some explanations http://www.efunda.com/designstandards/g ... lspecs.cfm
If you're really crazy - you can look into the term GR&R (Gage Repeatability and Reproducibility )http://www.qualitymag.com/articles/8681 ... d-gage-r-r
and
If you're totally off the deep end - you can look up ANSI/ASME Y14.5-2009 Dimensioning and Tolerancing specification
I would love to see a copy of BSA's wheel manufacturing drawing. It would be very interesting to me to see if they are setting any controls on the wheel dimensions and form or if it's just squirt some plastic into a mold and call it a day.
Laserman,
Thanks for the comments. I am trying to offer a really nice product, without fleecing everyone. Honestly, the magnets to hold the allen wrench were a high end touch, but they are a pain to install that is definately not reflected in the price.
The pinewood has offered alot of opportunity to talk and discuss a lot of things with my son and manufacturing is one of them. I think they should do a How it's made show on the Pinewood Derby kits....
Bore condition could certainly play a role in the quality of the wheel.
Measuring and understanding the bore and it's condition and or form could prove quite difficult with it's small size. You can visually see defects in some of them, like depressions. Are those helpful or hurtful - I have no idea. Some say that is where using single grooved axles helps, as it eliminates the amount of area where defect could be present in your riding contact area and that is a very logical theory.
My gage does not provide the "real" runout of the wheel, it provides a real life usage conditions test that also picks up other cylindrical form problems with the wheel if you are using the wide tip. But hey, you have to call it something and that was close enough for this application.
To truly measure runout, you would have to measure it to the axis (theoretical centerline) of the bore. That is not really a practical option in our case. Even if we could do that, we would want Total Runout, not just Runout - which is a different measurement. Also, you would not see any form error in your bore show up like you may or may not see with my gage. The idea was to keep it simple and practical to the application with a quick go-nogo check.
If you're board, here is a link that might help with some explanations http://www.efunda.com/designstandards/g ... lspecs.cfm
If you're really crazy - you can look into the term GR&R (Gage Repeatability and Reproducibility )http://www.qualitymag.com/articles/8681 ... d-gage-r-r
and
If you're totally off the deep end - you can look up ANSI/ASME Y14.5-2009 Dimensioning and Tolerancing specification
I would love to see a copy of BSA's wheel manufacturing drawing. It would be very interesting to me to see if they are setting any controls on the wheel dimensions and form or if it's just squirt some plastic into a mold and call it a day.
Laserman,
Thanks for the comments. I am trying to offer a really nice product, without fleecing everyone. Honestly, the magnets to hold the allen wrench were a high end touch, but they are a pain to install that is definately not reflected in the price.
The pinewood has offered alot of opportunity to talk and discuss a lot of things with my son and manufacturing is one of them. I think they should do a How it's made show on the Pinewood Derby kits....
Re: Pinewood Derby Car Mini-Lathe
knotthed, I understand what you're saying and I am going to read those links. I have a few more things I'm going to try with my practice wheel. If I make it worse that will also be educational. I have learned that a raw wheel can have less runout than a machined wheel you buy. That surprised me. The gage has already paid for itself.
Re: Pinewood Derby Car Mini-Lathe
I call the really good stock wheels "Unicorns"...... 
I'm sure it's a typical bell curve. From my previous wheel quality post .0005" to .012" and good/bad mold numbers change with the seasons. I could care less about mold numbers - althought I was initally caught up in the tube searching....gas and time from that alone would easily cover the cost of the gage for a scouts derby career......LOL wish I hadn't remembered that!
Even if you have a Unicorn wheel, if allowed to remove weight from the wheel, that is still very important to take advantage of!
Of recent interest, they have changed the plastic type or amount of recycled material versus virgin material being used. I don't recall the mold number but there is one in my batch that has some really nasty bubbles on the spoke face and some terrible molded debris on the OD. There is also another with big flashing on the inner tread edge.
I'm sure it's a typical bell curve. From my previous wheel quality post .0005" to .012" and good/bad mold numbers change with the seasons. I could care less about mold numbers - althought I was initally caught up in the tube searching....gas and time from that alone would easily cover the cost of the gage for a scouts derby career......LOL wish I hadn't remembered that!
Even if you have a Unicorn wheel, if allowed to remove weight from the wheel, that is still very important to take advantage of!
Of recent interest, they have changed the plastic type or amount of recycled material versus virgin material being used. I don't recall the mold number but there is one in my batch that has some really nasty bubbles on the spoke face and some terrible molded debris on the OD. There is also another with big flashing on the inner tread edge.
