Removing Wheel Seams

[rferrin]

When the rules say you can remove wheels seams, what are they talking about? I've searched all over the internet for what exactly the "seam" is on the wheel and how to remove it to make them lighter. Please include either a forum link, video link, or pictures so that I can learn how to do it.

[Stan Pope]

When the rules say you can remove wheels seams, what are they talking about? I've searched all over the internet for what exactly the "seam" is on the wheel and how to remove it to make them lighter. Please include either a forum link, video link, or pictures so that I can learn how to do it.

First time I've read of sprue marks referred to as "seams". But most likely the intent is to allow smoothing of the place on the wheel where plastic is injected into the form, then broken to eject the wheel. On BSA wheels, this used to be on the outer tread surface and sometimes required serious smoothing! The most recent vintage BSA wheels have the injection ports located on the inner face of the wheel rim, and are not objectionable so no special removal is needed. Pictures are on http://winderby.com/m02_040829.html" target="_blank

If you are working with some other wheel types, tell us the details and perhaps someone who has worked with 'em can share his expertise.

[frontosacam311]

Royal Ranger wheels have a seam smack dab in the middle all the way around the wheel and I've actually seen it referred to this in RR rules in the past.

[Stan Pope]

Royal Ranger wheels have a seam smack dab in the middle all the way around the wheel and I've actually seen it referred to this in RR rules in the past.

Well, if the wheels in question are Royal Ranger, then ...
First I'd evaluate the need to "work" the wheel. Is the tread irregular? How much variance is there in the radius around the wheel tread? Can you improve the variance or are you more likely to make it worse?

The normal gage for measuring wheel radius variance is a "dial indicator." The resulting measurement, the difference between maximum and minimum radius, is called "radial run-out." If you don't have one, see if you can borrow one and get assistance learning to apply it. Then apply it to the wheels AND apply it to whatever you might use to spin the wheels for altering the tread surface. For instance, if you will hold the wheel in a mandrel and chuck the wheel in a drill press or electric drill, measure the run-out of the mandrel while it is turned in the drill. Run-outs of 0.003" are not unusual and the run-out of the drill-mandrel limits the tread run-out that you can accomplish when smoothing the tread!

Also, evaluate the weight of the material that you would remove from the wheel. Since it is in the area of the wheel's periphery, removing material will reduce the wheel's radius and will require the wheel to spin faster in order to reach a given car speed. Evaluate the energy expenditure for the wheel to reach the finish line ... less is better!

Finally, if you decide to work the tread, decide what you will use. It could be the sharp edge of a chisel or knife or it could be progressively finer grades of sandpaper.

[whodathunkit]

First time I've read of sprue marks referred to as "seams". But most likely the intent is to allow smoothing of the place on the wheel where plastic is injected into the form, then broken to eject the wheel. On BSA wheels, this used to be on the outer tread surface and sometimes required serious smoothing! The most recent vintage BSA wheels have the injection ports located on the inner face of the wheel rim

Stan, I have some older vintage wheel photos showing seam marks you tuched on.
50's thin wheel.. 60's wide wheel.

70's wheel showing the seams in tread

[frontosacam311]

Radial run out averages roughly 0.007" while lateral run out is much less. I can get better results for less money with my homemade poor mans lathe than my Harbor Freight 7x10 but I am self taught, no guidance except forums and on a tight budget. The HF has 0.002" run out which transfers to the wheel, just doesn't cut it for me, totally unacceptable. For under $30 and some scrounging around I can get the run out under 0.001" or less. Materials used were a 2" sharp chisel, .125" gauge pin sanded to .122", Harbor Freight dial indicator, nut/bolt/washer and an aluminum C shaped channel. I'm slowly learning to use the actual lathe but I'm more focused on alignment and tuning at this point in the game than reducing an extra 0.001" run out. One thing to be noted abut RR wheels is they should be checked for static balance, I've encountered wheels with air pockets/cavities. Out of cherry picking 3-4 kits I can usually find 3 high quality wheels that pass the three critical tests that only require light sanding to remove the mold mark.

[frontosacam311]

The seam barely shows up in the image. To shave wheel just unbolt indicator and the blade rests on top, turn wheel with finger. Takes a bit of practice but I'm happy with it.

[Stan Pope]

Radial run out averages roughly 0.007" while lateral run out is much less. I can get better results for less money with my homemade poor mans lathe than my Harbor Freight 7x10 but I am self taught, no guidance except forums and on a tight budget. The HF has 0.002" run out which transfers to the wheel, just doesn't cut it for me, totally unacceptable. For under $30 and some scrounging around I can get the run out under 0.001" or less. Materials used were a 2" sharp chisel, .125" gauge pin sanded to .122", Harbor Freight dial indicator, nut/bolt/washer and an aluminum C shaped channel. I'm slowly learning to use the actual lathe but I'm more focused on alignment and tuning at this point in the game than reducing an extra 0.001" run out. One thing to be noted abut RR wheels is they should be checked for static balance, I've encountered wheels with air pockets/cavities. Out of cherry picking 3-4 kits I can usually find 3 high quality wheels that pass the three critical tests that only require light sanding to remove the mold mark.

If your lathe suffers same as mine, the run-out is due to poor centering of the chuck. After I removed the chuck to try a collet holder, I replaced the chuck and used a live center in the tail stock to help center the chuck before snugging down the nuts that hold the chuck in place. Run-out now approx. 0.001".

However, I am not satisfied with that, and I use the lathe differently ... I cut a short-pin mandrel from 5/8" dia stock and use a clamp held in place by the tail stock live center (lowest inertia live center that I could find). The short-pin mandrel gets cut fresh anytime I must loosen the chuck!

Some pix at http://www.stanpope.net/pictures/index. ... lamp%20etc. BTW, the short clamp is easier to use than the long clamp! I cut the long clamp as part of an experiment in undercutting the tread. But it is too hard to center properly when mounting a wheel. The pin on the mandrel is less than 1/8" long ... needs to be just long enough to engage the wheel bore with no slop.

[frontosacam311]

Initially I looked into a 4 jaw chuck but passed on it to go with a collet system. Glad I was patient and waited on both. Very helpful pics, thanks for sharing. Looks like I got my work "cut out" for me

[Stan Pope]

You are welcome.

Background:

I selected the outer edge of the bore for locating the wheel in X-Y and the "spoke face" of the wheel for controlling orientation. This selection seems good.

For reaming the bore (0.098") I use a ream guide which uses the same locating criteria! Pix at http://www.stanpope.net/pictures/index. ... am%20Guide

Sporty reported back "good results" when he applied this method with his lathe, although I think that he never reams bores.

These locating points/surfaces are different than those used by most others, but they seem to produce quality results. You decide for yourself what you prefer.

[Stan Pope]

BTW, in cutting the mandrel, I cut across the face, leaving a center pin of approx. 1/8" dia. and 1/8" long. Then I cut along the pin toward the face until the dia is approx. 0.100". Then I use a small file and emery paper to taper the pin by small amounts until the wheel just slides on with slight pressure. Then I use more emery paper to smooth the face that will contact the spokes.

Since the pin is quite short, it is easy to chuck last year's mandrel, cut 1/8" off of the face using the leftover pin as a guide. When the face is complete, I zip off the excess pin.

I think that it is pretty important to polish the locating pin so as to avoid scratching the part of the bore that it touches. Also be careful to get its size "just right" to avoid deforming the outer corner of the bore!

Designing a mandrel for Royal Ranger wheels might be a bit more complicated ... picking a plane area on the face of the wheel which is reliably perpendicular to the bore is essential. Similarly, the clamp should press the opposite side of the wheel and be approximately opposite the mandrel face contact area.

[frontosacam311]

This info is priceless thanks again for sharing. Pics are great too.
For now on the Royal Ranger wheels I'm going to cut the mandrel like stated slightly over and polish to the diameter of the bore and leave it 1/16" shy of the bore length so I can square up then bevel the hubs up to a 1/32" on each side if needed. Lateral run out removal is next to nil and the tread run out is the biggie, no under cutting like an open face wheel. I cant all the wheels which leaves me most concerned about the condition of the outer edges of the bores where contact is made. My current method of bore polish using sucker sticks leaves the bores looking like black ice and a centered axle groove is just added insurance. I don't have as much confidence in my ability to square a part of the wheel outer surface and have that transfer over to the bore to be able to use your recommended technique, maybe someday but not quite there yet.

For the BSA style I'm going to follow your method to a T, good winter project for me.

[Stan Pope]

... Lateral run out removal is next to nil and the tread run out is the biggie, ...

When you camber the wheels, lateral run-out becomes more of a problem than if the axles are level. Don't do anything that worsens the lateral run-out!

A long alignment pin on the mandrel is much more time consuming to prepare and presents a greater risk to the integrity of the bore. Furthermore, the short alignment pin does not provide a "holding function" ... that is provided by the clamp acting against the rim outside of the bore and hub! The pin/bore interface simply holds the wheel in place while the clamp is tightened! Rethink the Royal Ranger process and see if you can design a method that does not require it!

[frontosacam311]

I finally understand the benefits of your setup now, thanks for the patience! Looks like I need to fabricate some jigs and test them out for accuracy. I'll report back with pics and updated progress when I have something worthwhile. It sure would be nice to leave the bore mainly untouched and fresh. Since were on the topic of RR wheels there is one thing that stumps me to this day. That is the slight bore taper which is marked by a slight recess/indentation of 1/64" on the smaller side of the bore while the other side is flush. Not sure if the tapered down side would face the rear cambered axle heads while the front DFW would be reversed and towards the car body- figured any toe would be best against the axle head in back and body in front. Testing would be hard unless headless axles were used in the test. Do you think that having the taper one way or the other could make a difference? I mean it might throw off the camber a fraction of a percent or toe in/out slightly depending which way the taper was. Swerved off topic but this is something that has me befuddled and since it's ainy a BSA forum didn't want to start a new thread. Sorry OP for hi-jackin your thread.

[Stan Pope]

Well, some taper in the bore is necessary in order to get the wheel out of the mold! I suspect that it makes no difference, but that is just a SWAG. A possible concern is that the axle rubs over a longer distance on the large end of the bore, so the wheel would tend to turn in the direction of the large end! But the effect is probably so small as to be lost in the noise. If you have a RR wheel reject or two to send I'll try to help identify a mandrel & clamp design that would work for you.