Regrooving Skate Wheels Using a Metal Lathe

Intro: Regrooving Skate Wheels Using a Metal Lathe

I have been participating in the sport of Jam Skating (fancy rollerskating) for the last 6 years at my local roller rink.  Since the start I have been going through wheels, bearings, boots, and trucks/plates, not just because they broke but because they wore out. I have seen skate wheel regroovers before but I don't need need one if I have a metal lathe that is more precise any way.

So I set out to design a tool that skate wheels attach to and can be mounted on my lathe between centers.

**Before you attempt this project on the metal lathe you should be comfortable with turning cuts, facing cuts, and single point threading.  You should also be familiar with feeds and speeds appropriate for your lathe.**

STEP 1: Designing the Arbor

My criteria:
  •Mount between centers
  •Must be very accurate and repeatable
  •Must regroove all skate wheels

My sketch shows the mounting arbor where the counter bores of the wheel seat, it also show the taper nut that centers the wheel on the arbor.

STEP 2: Machining

Well, you will have to use your experience to machine this.  It is constructed out of 1 inch dia 6061 - T round aluminum.

Imagine making a "fake skate wheel" that is adjustable for clamping a wheel. 

STEP 3: Regrooving!!

At this step you should have a use-able arbor that accepts a skate wheel and mounts to your lathe.

1. Clamp the arbor in the chuck of the lathe.

2. Mount a wheel on the arbor.

3. Make sure the cutting tool has HIGH positive rake and is on center.

4. Move the tail stock up.

5. Set the lead screw for 20-28 TPI.

STEP 4: Making Threads

This is the final step for regrooving skate wheels.  Now for some machining science!

Since the wheels are made of a soft rubber (urethane) the cutting tool of choice needs to be extremely sharp, be presented on center, and have a high positive rake. This allows for the wheel rubber to be "cut" versus "smashed" as with 0 rake tools. Also since the wheel is 62mm in diameter the surface feet per minute is quite high. This is needed because at low speeds the tool could "tare" the rubber. I would suggest 150-400 rpm.


Feeds and speeds
•20 degreese positive rake, 
•.002 radius
•.030-.060 depth of cut
•150-400 rpm

STEP 5: UPDATE: Tool Holder

This latest idea uses a tool holder that presents the tool at 30 deg of positive rake!

Aluminum is a great material for the tool holder, use 1/4-20 set screws.

Comments

[Fly4aWhiteGuy]

Instructable to build a small lathe from scrap wood.

https://www.instructables.com/id/Mini-Wood-Lathe-Using-Scrap-Wood/

I'm thinking I can make the arbor with a couple of old bearings and an axle shaft.
I have a small metal lathe, so I could just center drill the ends of a bolt, threaded rod, or axles.

[Fly4aWhiteGuy]

I suggest an edit - Urethane is not a soft rubber. It's much harder than most rubber, but it's a plastic (polymer?) of some sort.

[Fly4aWhiteGuy]

https://en.wikipedia.org/wiki/Polyurethane

[randy.welch.39]

Would you be willing to sell me an arbor? I might purchase more than one can you please contact me thank you

[jmurray31]

Would you be willing to sell me an arbor? I have a lathe but admittedly am not very experienced enough to be able to successfully fabricate like that yet. My wife plays derby and really wants me to be able to regroove her many many sets of wheels.

[sk8burder]

I did freeze the wheels as my dad's friend advised me to do as well. So my method is intended for soft (76a-87a) skateboard/longboard wheels. I also intend to do the same for the 101a wheels I have. I use surform to cut the majority of the wheel down, to where the flatspots, ovals etc. are no longer present. I then face cut using a horizontal, zero rake tool bit I got from harbor freight. I do this to ensure a uniform finish, I check everything with a runout gauge and digital calipers after this step. It seems to work well enough, though it is a lengthy process. Any suggestions? I fear dry ice will be too cold and risk cracking the core(plastic) of the wheels? I also would like a way to remove more urethane quicker, while maintaining safety of not gouging the wheel, if there is one.

[sw.machinist]

Hm... Since I am also new to machining soft cast urethanes I have been doing some research. From what I can tell -and from experience- cutting soft cast longboard wheels (assuming softer than 90A) will require a SUPER sharp tool. Try grinding and honing your own HSS tool bit form 1/4 square bit to a RAZOR edge. Also high positive rake and possibly a burr edge. *I would recommend practicing on other old wheels of similar hardness first.*

Dry ice may cause harm, so maybe don't do it. But, experiment first on old wheels!!!

On wood turning round nose scrapers, people sometimes flip them over and grind them sharp from the bottom up. This causes a "burr" to form on the top cutting edge of the tool. This burr is not strong (so it won't last) but it is very sharp. You may have success trying that.

[sk8burder]

Thank you for the design! I recently moved up to a mini machine lathe and do not have tool bits yet. I am attempting to simply resurface my wheels with a smooth surface, any advise on what bits I should buy? Finances are tight, so I would hold out on buying a diamond tool holder if I can.

[sw.machinist]

Well it depends on the durometer (hardness) of the wheel. Urethane<Nylon<Acetal<Aluminum<Steel. For softer materials like Urethane skate wheels (88A-101A) you will have better luck with high rake, medium radius, and SUPER sharp. For skate board wheels you may try a zero rake indexable carbide cutter. Also putting the wheels in the freezer over night may help too. I may caution you on using hand-ground HSS presented horizontaly because this method is hard to achieve a sharp repeatable edge. [Also, the "burr" used on wood turning chisels is sharp but it doesn't last long].

**I will urge you to EXPERIMENT on "old" wheels (p.s. don't try to regroove your brand new vanilla backspins). Ask people around your rink for any old sets of wheels that you can have/ possibly cheap $.

[ironsmiter]

that's cute, that you think 400rpm @ 62mm is high speed :-)

If you feel confident in your wheel jig(and it LOOKS pretty darn nice) try this.
Stick the wheels in the freezer(or dry ice is even better) for a good long while.
Polish and hone the living snot out of your tool bit.
Set your height about 5mm above center.
As for feeds and speeds, you should be running closer to 2500RPM.
and of course, your feed/revolution stays the same(sorry, being from the middle of the USA, I only know it as IPM. how would you shorthand the metric, MMpM?)
But, If it works for you the way it is... go for it. Not like you NEED to be getting production speeds at home, on a project like this.

It's a great little project, and the end results look fantastic.

[sw.machinist]

Great tip! Well I'm in Colorado and my import lathe barely does 2000 rpm. With my half nuts I don't think I would be quick enough to disengage them at that speed.
•I guess I was talking about Threads Per Inch (1/2-20).
I'm not sure the diamond tool holder has enough front clearance for .250 in above center -- I thought about it though.
Look for the "Skate Nurse" regrooving machine. It gave me ideas.

[tsmith70]

It's closer to .197 actually, but I'm certain he meant .5mm which is about 20 thousanths (.019). The tool holder will be fine if you stay 1/64 above center, and this isn't too much more. To be honest, staying very slightly above center is not really needed, but above center can be better than below on soft plastics.

Perhaps a longer lead shank on the chuck side of the arbor would make you more comfortable with a higher speed? It will be difficult to spin it too fast since you are taking such a light cut to begin with. Oh, a final thought, tossing it in the freezer overnight will help a lot, but might make it hard to mount depending on how much slop the shoulders of your arbor have.

[ironsmiter]

My oh my. Good catch. Five mm? Could you imagine? Yes, definately 0.5mm was what I meant to say.

[tsmith70]

Any time brother!