Ideas towards Cub-centric wheel improvement...

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Vitamin K
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Ideas towards Cub-centric wheel improvement...

Post by Vitamin K » Wed Oct 07, 2015 2:13 pm

Hey Derbians,

So I'd like to do some more "thinking out loud" here, and I'm relying on you guys (and gals?) to come poke holes in the flaws of my reasoning, as you see fit.

So here's the problem I want to solve: There's no good way for cubs to true up their wheels that can be done without expensive equipment. There exists the Derbyworx wheel shaver, but I've actually become less pleased with this tool, the more I've worked with it and evaluated the output.

Here are my issues with the Pro Wheel Shaver:
- The pin is rather loose in the bore of the wheel, leading to slop and potential uneven pressure on bore.
- It requires a LOT of time and patience to get a good result
- The blade is finicky and snags easily.
- Turning the wheel by hand sucks.

What I'm looking for is a solution that is:
- Straightforward: A cub should be able to use this without too much trouble
- Affordable: This is debatable, but I'm thinking 100 bucks or less -- far less than even a cheap metal lathe
- Effective: Should be able to true the outside of a wheel to within .001" runout, parallel to the bore.

Ideas sort of rattled around in my brain for a while, but then I saw these plans for a homemade metal lathe. Based on the parts used, I think that I might have an idea of how I'd tackle the problem. Of particular interest to me were the support blocks and the bearings.

So, here's the basic plan: We need a way to mount a wheel on a turning mandrel that allows for some way to either sand or trim it with a tool. The wheel needs to turn with low runout and, ideally, the method should NOT put friction on the inside of the bore as a result of the truing process.

So the meat and potatoes of this design would be a turned cylinder with a main diameter that would fit into a standard sized bearing, and a protruding "pin" that would snugly fit a BSA wheel with an interference (friction) fit for working. The other end of the cylinder would have a pulley guide affixed for connection to some kind of power source for turning (possibly a drill, or dremel, or dedicated motor). The cylinder would be supported by two bearings, which would sit within two support blocks, similar to those shown in the aforementioned lathe plans.

Here is a very bad sketch of what I'm thinking of:

Image

Because the fit would be a press-fit, it would require that the bores be reamed to a uniform size before working. I believe the investigation done by Stan Pope would be helpful in this regard. I've listed 0.098 because that's what Stan was using, but possibly a smaller size would be appropriate? Regardless, a reaming tool would be required to make accurate use of the wheel-turner-thingie.

At this point, I've omitted any sort of tool holder or fitting. There are a few options that could be used. For example, a machining block wrapped in varying grades of sandpaper might be sufficient. Or an actual cutting tool might be preferable. The former is more in line with the 'light sanding' guidelines that a lot of Districts use, but the latter is possibly more efficient?

Anyhow, as before, just thinking out loud here. The ultimate goal would be to put more accessible tools into the hands of Scouts that could effectively yield quality parts without the need to resort to expensive equipment, or external services. All thoughts welcome. :)



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Re: Ideas towards Cub-centric wheel improvement...

Post by gpraceman » Thu Oct 08, 2015 9:49 am

Something like the Pitsco Wheel Lathe, modified to work with PWD wheels, might accomplish your goal.


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Re: Ideas towards Cub-centric wheel improvement...

Post by Vitamin K » Thu Oct 08, 2015 9:50 am

gpraceman wrote:Something like the Pitsco Wheel Lathe, modified to work with PWD wheels, might accomplish your goal.
Very similar concept. The size of the mounting pin would be the biggest concern, I think.



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Re: Ideas towards Cub-centric wheel improvement...

Post by knotthed » Thu Oct 08, 2015 12:28 pm

ER11 collet, with gage pins should provide a good mounting solution. Driving it cost effectively is the challenge.



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Re: Ideas towards Cub-centric wheel improvement...

Post by Vitamin K » Thu Oct 08, 2015 1:38 pm

knotthed wrote:ER11 collet, with gage pins should provide a good mounting solution. Driving it cost effectively is the challenge.
Well now, I like the way you're thinking! If I could just swap out pin gages, I wouldn't necessarily need to ream the wheel bores...I'd just have to select a gage that was appropriately sized to fit my wheel.

So let me see if I understand this properly...

I'd need one of these: Image

And a set of these: Image

And then I could mount the shaft of the collet extension into appropriately sized bearings, which would sit in appropriately sized mountings. So then, to turn the sucker, I could just rig up a pulley system between the back of the shaft and some kind of electric turny-thing, like a drill or a rotary tool, no? :scratching:



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Re: Ideas towards Cub-centric wheel improvement...

Post by knotthed » Thu Oct 08, 2015 4:44 pm

Yes, but controlling the axial movement is the tough part. Maybe it could be conquered adequately with a press fit bearing or using some sleeve retaining compound, since the cutting forces are not that high.

search the terms ER and Spindle or Headstock, those two terms should get you pointed in the right direction.

I just think the cost builds up too quickly to make it worth while.

Although, perhaps it could be powered with a drill press as your power source. That should give a close enough cutting rpm for the wheels and a little flexibility.



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Re: Ideas towards Cub-centric wheel improvement...

Post by whodathunkit » Thu Oct 08, 2015 7:45 pm

Vitamin K,

Like your Ideas on this!
Just to toss some ideas your way for motors.
Blender motor or a variable speed bench polisher.
http://www.utopiatools.com/ProductDetai ... AqjD8P8HAQ

Don't know if you have a variable speed Foredom flex shaft tool or not.
If you do you might like the Matt mini lathe.
http://www.metalliferous.com/images/CA2803.jpg
https://www.youtube.com/watch?v=WSQwsLOHJrY

The ER 11 collet might chuck up in the flex shaft.. Just tossing some ideas out your way.


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Re: Ideas towards Cub-centric wheel improvement...

Post by Vitamin K » Sat Oct 10, 2015 8:42 am

Hey guys, thanks for your thoughts on this little thought experiment of mine.

Whoda: I have seen that little jewelry lathe before, and it looks kind of neat. Of course, at the selling price of around $175.00, it's already outside of the range of what I was hoping to stay within. :) I think by the time I spent that money, I'd just go whole hog and get one of these micro lathes from Grizzly.

Knotthed So, I'm still doing some digging on the whole 'anchoring' issue. I think that if I could solve that piece of the puzzle, I'd have something that I could run with. The possibility in my mind would be to use a bearing with an ID that matched the OD of the collet chuck shaft, and then affix it into place with loctite retaining compound. This presumes that I'd be able to slide the bearings freely to the proper point along the shaft, and that once bonded with compound, they'd stay sufficiently secure.

Presuming both of those things are workable, the price rundown is looking something like this:

- 1x Collet Extension Rod: $15
- Assorted size collets: $10 (ebay prices)
- 2x Bearings ($7/each) $14
- 2x Bearing Supports ($13/each) $26
- Pin gages $10

So that's about $75 bucks thus far. But there also needs to be some kind of pulley mechanism to link with the hand drill or rotary tool to turn the shaft, and also some kind of tool holder to actually cut or sand the wheel.

If I could find a cheaper solution to hold the bearings, I could knock off a chunk of the price. The bearing supports are great if you want to, say, make a movable setup on a track of extruded aluminum, but I might not need to worry about that. Possible I could get away with something cheaper (bored wooden blocks?) to hold the bearings.

Gonna keep thinking on this, and may, at some point, just buy some junk to see what I can put together. That is, when my wife isn't looking. :angel:

Edit: So, turns out, I can get parts cheaper from China, so those bearing supports I can get for a fraction of the cost if I don't mind waiting on overseas shipping. Might pay a penalty on quality, but still...possibly good enough for a Scout-level wheel improver thingie that actually does something.

Edit #2: A new possibility! So there exists these "pillow block bearing" sets that not only have the bearing set into the mounting, but include a set-screw to hold your rod in place! Thus, I'd eliminate having to futz with fitting the bearing into the mounting AND I'd have a locking solution.

Image



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Re: Ideas towards Cub-centric wheel improvement...

Post by whodathunkit » Sat Oct 10, 2015 4:36 pm

Hay Vitamin K,

Can't blame you for wanting to go whole hog for the Grizzly lathe.
I'd like to have one to tinker with myself, ;)

Don't think any one would blame you for staying in the the range you were looking to spend for a lathe
as well... so I'll toss this link your way.
http://www.ebay.com/itm/Mini-Motorized- ... 0380wt_924

Anyhow homemade tools are cool as well.. best of luck with your lathe project.


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Re: Ideas towards Cub-centric wheel improvement...

Post by bracketracer » Sat Oct 10, 2015 8:30 pm

whodathunkit wrote:Hay Vitamin K,

Can't blame you for wanting to go whole hog for the Grizzly lathe.
I'd like to have one to tinker with myself, ;)

Don't think any one would blame you for staying in the the range you were looking to spend for a lathe
as well... so I'll toss this link your way.
http://www.ebay.com/itm/Mini-Motorized- ... 0380wt_924

Anyhow homemade tools are cool as well.. best of luck with your lathe project.
Whoda, might check the capacity of that little lathe before you order one. It only handles 20mm in diameter. Too small to mount up a stock BSA wheel.



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Re: Ideas towards Cub-centric wheel improvement...

Post by Vitamin K » Sat Oct 10, 2015 9:43 pm

bracketracer wrote:
whodathunkit wrote:Hay Vitamin K,

Can't blame you for wanting to go whole hog for the Grizzly lathe.
I'd like to have one to tinker with myself, ;)

Don't think any one would blame you for staying in the the range you were looking to spend for a lathe
as well... so I'll toss this link your way.
http://www.ebay.com/itm/Mini-Motorized- ... 0380wt_924

Anyhow homemade tools are cool as well.. best of luck with your lathe project.
Whoda, might check the capacity of that little lathe before you order one. It only handles 20mm in diameter. Too small to mount up a stock BSA wheel.
I wanna say that the 20mm refers to the maximum diameter of the stock you can chuck. Probably big enough to cut a wheel mandrel from, at least.

That said, I haven't heard great things about these little mini-lathes. Lots of detractors in regards to tolerances and slop. Still...it'd be a fun machine to play around with. I just don't wanna risk my own hundred bucks on it. ;)



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Re: Ideas towards Cub-centric wheel improvement...

Post by knotthed » Tue Oct 13, 2015 6:33 pm

Vitamin K wrote: I just don't wanna risk my own hundred bucks on it. ;)
That's exactly what you're doing going down the homemade path, you just don't realize it yet.

It doesn't have to be ball bearings(all though preferable in my opinion) - old lathes used bronze bearings/bushings - but they will wear faster.



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Re: Ideas towards Cub-centric wheel improvement...

Post by Vitamin K » Tue Oct 13, 2015 8:18 pm

knotthed wrote:
Vitamin K wrote: I just don't wanna risk my own hundred bucks on it. ;)
That's exactly what you're doing going down the homemade path, you just don't realize it yet.

It doesn't have to be ball bearings(all though preferable in my opinion) - old lathes used bronze bearings/bushings - but they will wear faster.
Shhh, let me have my fun! ;)

I've ordered the collet chuck extension rod, a 2-3mm spring collet, and two of the pillow bearings. Thus far I've spent about 30 bucks. Once I put those bits together and see if they will turn a pin gage with low runout, I'll start messing around with some way to provide power to it.



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Re: Ideas towards Cub-centric wheel improvement...

Post by Vitamin K » Wed Oct 14, 2015 9:59 am

Waiting for my parts to come in. It'll be a while, since they're shipping overseas. I understand there's a cost to experimentation and whatnot. If this actually works, though, I think it will be nice to have a "recipe" to offer folks wanting to do basic wheel mods on a budget that doesn't accommodate a full-blown lathe.

So, thinking ahead a bit to something to use to build the tool holder. On the mini-lathe tutorial linked above, the dude actually built himself a miniature XY table, but, people, I'm not that good (plus, I don't know how to braze metal). So...I need something prefab.

So what I'm thinking is get my hands on one of these guys:

Image

What it is is an XY stage for a microscope, used to make small adjustments to your slides while you're looking at 'em through magnification. I figure that the actual range of motion for a tool used on a wheel will be, ideally, quite small, so something designed for adjustments under magnification might do well.

The part is about 20 bucks, which isn't too bad. Would raise the total cost of the project to fifty bucks, which just leaves rigging up some kind of linking mechanism between the shaft and power source (dremel or hand drill).

Going to evaluate the turning/chucking parts before I buy anything new, but thought I'd share my braindumps. :)



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Re: Ideas towards Cub-centric wheel improvement...

Post by bracketracer » Wed Oct 14, 2015 9:16 pm

VK, I'm not sure that a slide holder is going to be up to the task of cutting plastic?
If there's any deflection your accuracy will go out the window.

Too late now since I see you've started ordering parts, but what about perusing craigslist for a small used wood lathe for your starting point?



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