Creating BSA Razor Wheels with the Pro Wheel Shaver

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
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Nitro Dan
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Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by Nitro Dan »

Last season, some of the members here were asking how I made my BSA Razor Wheels. I was hoping to provide instructions and pictures this past summer, but one thing lead to another and it all got "shelved" in the process. I can say that I've been refining my process over the last few months and finally have it down to a point where I feel comfortable about posting some pictures and detailed instructions. I'm hoping some of you will be able to use this information and possibly develop this process even further.

Let me start by saying the first thing you need to do is check your rules as to whether or not these wheels would be legal in your races. Many of the kid races do not allow wheels to be altered like this; however, most Open Class or Outlaw/Renegade type races will allow them. If the rules don't say if they are illegal or not, be sure and ask someone on the PWD Committee for clarification. Trust me, it will save you a lot of headaches in the long run.

The tools you are going to need are a level block (wood or metal), a wheel mandrel, the Pro Wheel Shaver II, a sharp chisel, a drill press and a large sanding drum attachment. If you don't have a sanding drum for using in your drill press, I recommend going to your hardware store and getting one. A set usually costs less than $20 and is well worth the money.

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Next, mount the wheel in the wheel mandrel, and chuck it into the drill press. Place the block on your drill press table and adjust the table height so that the lower outside edge of the wheel tread is about 1/16" below the top of the block. This doesn't need to be a precise measurement, just close.

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Start the drill press on its slowest speed and place your chisel flat side down on top of your block. Slowly move the corner tip of the chisel into the wheel tread. This will start cutting a groove into the tire tread.

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Continue pushing the chisel corner tip into the tread and within about 20 seconds you should be able cut through the entire wheel.

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Stop the drill press, remove the mandrel and separate the wheel tread from the mandrel.

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Remove the wheel from the mandrel and repeat the process with the remaining wheels. I've used both the Pro Wheel Mandrel and the PineCar Wheel Mandrel with this process. Although the Pro Wheel Mandrel holds the wheel tighter, the torque placed on the wheel when being cut can sometimes deform the outside wheel bore hole or even split the hub. The wheel is pretty much ruined if that happens. When using the PineCar Wheel Mandrel, I found that it would slip at times while the wheel was being cut, if the wheel was not as tight as possible in the mandrel. To tighten it I use pliers to hold the shaft and tighten with a flat head screwdriver. Once tight it performs real well and has never deformed the wheel bore or spit the wheel hub.

Once all four wheels have had the majority of the tread removed, it's time to start the shaving process with the Pro Wheel Shaver. Set the blade down 3/8" and the hub tool out to 3/4". So far, I've found this to be the best setting for making a wheel tread of about 3/64" to 1/32" wide. The side of the blade that normally is used to true the inner edge of the wheel will do the cutting. Apply pressure slowly so the blade doesn't dig in too much. If it accidentally does, try to force it past the point. If you back off and then try to take off less, you'll leave a crease in the plastic (which may or may not shave out). Continue to trim the wheel until the blade no longer seems to be shaving the wheel, at that point the inside hub should be flat up against the hub tool. It usually takes me about 15 to 20 minutes of slow shaving to complete one wheel. Also, don't try and work the wheel with unprotected fingers like in my pictures. Get yourself a pair of tight leather work gloves and use that to turn the wheel. Trust me, my fingers were sore and cramped for a week after doing my first set.

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You can push the envelope here if you want and go for a true razor edge on the wheel, but remember that there is a series of rough tread bumps on the outside edge of the wheel. If you cut to thin, you'll wind up riding on that rough edge (of course you could just sand that rough part down ahead of time). Once you have trimmed the inside edges on all four wheels, go ahead and true the wheels in the normal manner for roundness with the Pro Wheel Shaver. This should be very easy to do, as shaving a 1/32" wide wheel tread is a lot easier than shaving one that is 1/2" wide.

This next step depends on what your rules state. If your rules state that the words "BSA Pinewood Derby" have to be visible on the outside of the wheel, then skip this step. The rules with our pack state that the words "BSA Pinewood Derby" have to be visible on the outside of the wheel, or the words "Official BSA" have to be visible on the inside of the wheel (so they can prove it is a BSA wheel). Because of this, I found a way to work the outside of the wheel in the same method as trimming the inside of the wheel using the Pro Wheel Shaver.

Take your Pro Wheel Shaver and set the blade down 7/16" and the hub tool out 1 and 3/32". Turn the outside face of the wheel inward so the spokes are facing the hub tool. Then slowly apply pressure while turning the wheel. This will shave the wheel flat on the outside. Keep turning the wheel until the blade is no longer shaving the plastic and the wheel is tight up against the hub tool.

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This should bring it down the outside of the wheel to about the same height as the spokes on the wheel. Repeat the process for the remaining wheels. Again, you can push the envelope here if you want to, just keep an eye on the wheel thickness when doing so.

If the shaver leaves the outside of the wheel with a few gouges where it bit in too deep, don't worry about them. Take some 400 grit sandpaper and lay it face up on a flat surface. Take the wheel by the hub and place it face down (spokes side down) on the sandpaper. Move the wheel in circular motions while applying light pressure. Check the wheel every few seconds until the any unwanted roughness or gouges are gone. Repeat the process with 600 grit sandpaper in order to shine the plastic so it will appear as smooth as the rest of the wheel. Below is a picture of a flattened and rounded wheel, side by side.

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The next step is to reduce the hub on the razor wheel. I came up with a number of ways to do this, but one of them easily and quickly did a better job than the rest. This method requires you to create a simple tool. Find a strip of rigid sheet metal that is about 3/4" to 1" wide and 4" to 6" in length. Drill a hole in the center of the metal strip that is 5/16" wide. The best way to do this is start with the smallest drill bit you have and slowly work your way up (changing out drill bits) to 5/16". In the picture below I created my tool from a computer backing plate that was used to cover up the slots in the back of an old tower computer case (I simply cut off the 90 degree bend on one end of the plate, with some tin snips).

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Push the razor wheel hub through the 5/16" hole in the plate.

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Put the largest sanding wheel you have into your drill press and turn it on. Pick up the razor wheel and plate together. Place both your thumbs on the outside face of the wheel (the spokes side) and grip both ends of the metal place with your index fingers. This leaves the hub sticking straight out on the other side of the plate. Guide the hub into the sanding drum and let it grind away (just a few seconds) until the metal plate barely touches flat up against it. In the picture below I'm using a 60 grit sanding sleeve on an oscillating spindle sander, but a sanding drum on a drill press is just as effective.

EDITED NOTE: After further testing it has been determined that the newer 2009 wheels are faster with the hub intact and indented into the body of the car. Please read all posts in this thread before creating your razor wheels. -Nitro Dan

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As soon as the metal plate touches the drum, pull the wheel and metal plate away. The hub should now be ground down to the same thickness as the metal plate. Repeat the process on the remaining wheels.

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Next remove the Pro Wheel Hub tool from the Pro Wheel Shaver. Push the Pro Hub Tool into each wheel bore from the spokes side of the wheel. This will pop out any ground plastic that might have got into the wheel bore and clear out any melted hub plastic that might be slightly covering the wheel bore entrance on far side (the hub side).

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Next, get about three levels of fine sandpaper (I use 220, 400 and 600 grits). Use the flat side of the Pro Hub in the normal manner, starting with the lowest sandpaper grit and working your way up, until the inner wheel hub is nice and smooth like the rest of the wheel. Repeat for the remaining wheels. At this point you are pretty much finished, unless you want to go ahead and polish the insides of the bores with Micro Gloss.

The wheels I'm using in this demonstration are the older (pre 2009) wheels. Their weight, if made flat on the outside of the wheel, should be around 1.5 grams per wheel (even less if you are pushing the envelope). If you leave the wheel rounded on the outside weight may be around 1.8 grams per wheel. I haven't yet tried this process on any of the new lighter wheels, but plan to do so sometime in January or February. I'll post back then with the results I find.

Here's a set of finished wheels standing on edge to show the thickness of the tread.

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Here's another of the same set laying the spokes side up.

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And finally a picture of the same set with the hub side up.

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If you click on any of the pictures it should blow them up so you can get a closer up more detailed look.


-Nitro Dan
Last edited by Nitro Dan on Wed Apr 21, 2010 3:38 pm, edited 1 time in total.
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bigtex
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by bigtex »

Wow. Very nicely documented! :clap:

Well done.

Will have to try this next month!
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by sporty »

I wanted to so say thank you for sharing you're process and this will help so many people who want to try there own razor wheels.

:bigups: :bigups: :bigups:


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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by TOU »

AMAZING WORK! Thx for posting it!
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by AlabamaDan »

:clap: Thank you so much. We've been using a lathe that a friend has, but it's a hit or miss situation on when we can do it. This I should be able to do in my own garage! :thumbup: Thank you so much!
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by gpraceman »

I love these type of low budget ways to do things. :bigups:
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by FatSebastian »

Has anyone tried this with the new-style 2009 wheels? If so, are there caveats to the process described here?
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by doct1010 »

FS,
Having made numerous sets using the old wheel, I can only imagine the new wheel should be easier given the thinner tread. The only problem one may encounter is the more narrow hub; it may not stand up as well to the mandrel pressure required to hold wheel stable.
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Nitro Dan
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by Nitro Dan »

FatSebastian wrote:Has anyone tried this with the new-style 2009 wheels? If so, are there caveats to the process described here?
I just finished making three sets using the new wheels. Hub held up fine in the wheel mandrel and I even did one set using the Pro Wheel Mandrel. The sets I made had the outside of the wheel left rounded (raised lettering intact). I plan to make a set with the outside flattened shortly.

The process and Pro Wheel Shaver settings are the same. The only thing I was concerned about was the 5/16" hole in the metal plate that I use to grind the hub down with, but the hole worked fine without incident. I would suggest making that hole 1/4" for the new wheels, just to make it look better.

The one surprising result was that the wheels turned out to be even lighter than before. With a rounded outside, the wheels only weigh 1.3 grams each. I have a feeling that once I flatten the outside of the wheel, a 1.0 gram wheel may be possible. :bigups: I'll post back and let you all know what I discover.

-Nitro Dan
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by FatSebastian »

Nitro Dan wrote:ThThe only thing I was concerned about was the 5/16" hole in the metal plate that I use to grind the hub down with, but the hole worked fine without incident.
Why grind down the hub? It seems to contribute only a small amount to the mass moment of inertia and cross-sectional of the wheel. Is there any benefit to leaving it intact?
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by gpraceman »

FatSebastian wrote:Why grind down the hub? It seems to contribute only a small amount to the mass moment of inertia and cross-sectional of the wheel. Is there any benefit to leaving it intact?
Removing most of the tread and keeping the hubs intact, you do increase the distance from the inside wheel edges to the guide rail. On the rears that may not be a bad thing, if you are RR, but you wouldn't want that on the DFW. If not doing a RR, you do have further for the car to travel to hit the rail, which would be more of an impact and more energy lost.
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

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I see Graceman beat me to it. Also if the car drifts more to the right or left on a tight track (lanes close together) it may interfere with cars running in other lanes. Reducing the hub allows the wheels to hug closer to the rail, giving you a better run.

If you want to leave the hub intact, your could always reverse the wheel so that the hub is outward towards the axle head. The only problem here is that when reversed, the face of the outside wheel would have the ability to rub against the car body. With that area being increased, there would be more surface contact area then if just the hub was there. I thought about putting a small washer there to act as a spacer, but most of the rules I see still don't allow this.

-Nitro Dan
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by Stan Pope »

Nitro Dan wrote:I see Graceman beat me to it. Also if the car drifts more to the right or left on a tight track (lanes close together) it may interfere with cars running in other lanes. Reducing the hub allows the wheels to hug closer to the rail, giving you a better run.

If you want to leave the hub intact, your could always reverse the wheel so that the hub is outward towards the axle head. The only problem here is that when reversed, the face of the outside wheel would have the ability to rub against the car body. With that area being increased, there would be more surface contact area then if just the hub was there. I thought about putting a small washer there to act as a spacer, but most of the rules I see still don't allow this.

-Nitro Dan
A simple answer is to inset the wheels by the amount of hub that was not removed (plus the usual 1/16"). Few rules that I've seen restrict narrowing the body.
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by FatSebastian »

:thinking: My reason for asking is two fold:

1) After the inner hub is removed, is there noticeable play between the wheel bore and axle to cause rocking / steering of the wheel on the axle while in motion?

2) A lot of the bores of the newer wheels are recessed toward their centers. Would uneven bores complicate things if the inner hub is removed?
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Re: Creating BSA Razor Wheels with the Pro Wheel Shaver

Post by doct1010 »

FatSebastian wrote: Why grind down the hub? It seems to contribute only a small amount to the mass moment of inertia and cross-sectional of the wheel. Is there any benefit to leaving it intact?
More than adequate explanations have already been offered. What I can add, the hub, for us, was the weakest link. We tried several depths from flush to full. The more narrow the sloppier imo. We mitigated somewhat with larger axle (AWANA) and ultimately went to an insert. This of course for experimantal cars in outlaw only.
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