New bearing holder idea

I’ve been preoccupied for the last month or so with the purchase and installation of a significant piece of equipment in the shop. It’s a machine called a “water jet”. It will cut virtually anything using high pressure water (50,000 psi in our case) and abrasive. We will use it to cut stainless steel, aluminum and plastic mostly. I’ve heard of water jets being used to cut diapers, insulation, granite, cakes (yes cakes!), glass …

Yesterday we finally got it running for the first time - pretty exciting. You know that there’s some interest when the shop guys will hang around after hours on a Friday night just to watch it run.

Even though I personally won’t be running this machine, I MUST know what it’s all about and there’s no better way to learn how to run a machine than to use it. For some time I’ve had an idea for a new bearing holder design so today I made one using the new water jet.

I’ve created a gallery with some photos of the new bearing holder . I’m actually making an entire frame with the water jet but so far I’ve just photographed the bearing holders.

Basically, the bottom of the fork leg is an arc of the same radius as a 40mm bearing. The width of the fork leg at the bottom is 40mm wide and the thickness has been machined to 12mm - same as the bearing. The bearing is held in a “U” shaped retainer that’s been machined to accept the bearing with lips on both sides. The “U” retainer is attached to the bottom of the fork leg with a couple of screws coming in from the sides. The nice thing about this design is that it’s impossible to overtighten anything that will put a bind on the bearing. Also notice that the bearing is held with lips on both sides and the same lips extend along side the bottom of the fork leg to keep everything aligned.

I don’t like to blow my own horn but I think it’s a pretty cool idea. I intend to make a complete 24" MUni frame using the water jet and I’ll post more photos as the project progresses.


Absolutely beautiful, Steve! I can’t wait to see the whole muni finished and to hear how these bearing holders do after a bit of abuse.

That’s one big machine!


Looks like a nice design … How about if you extended the “U” section and instead of 2 screws; drill through so that you could run a skewer and quick release (for “no-tool” wheel removal)?..

That machine is huge! That’s a very creative design, can’t wait to see the finished product.

  • Frank

That is a cool design. I absolutely love watching you make these creations. I think the way those bearing holders is great. I really hate having to tighten the bearing holders on my unicycles for fear of damaging my bearings from going to tight.

Awesome idea!

Beautiful design as always, Steve

I think Steve’s company needs to sponsor a unicycle weekend! :smiley: What a cool toy. The only water jets I have are on my bath tub. I think they project H20 at a “little” under 50,000 PSI.

Nice bearing design. --chirokid–

Re: New bearing holder idea

Whoa! That’s equivalent to about 20 miles deep in the ocean if it went that deep. I think 7 miles is the deepest spot.

That’s amazing! What does it use as an orifice? Diamond?

Re: Re: New bearing holder idea

I guess the orifice is made of nothing at all, like most holes. I wonder what substance surrounds that orifice, though.:stuck_out_tongue:

I’m still worried about this machine being used to cut diapers. Surely removing them and disposing of them in the normal way is kinder to the baby? Should we call Social Services? :astonished:

That’s a great idea! I didn’t think I could make a quick release with what I’ve already got so I did what might be the next best thing: I machined a slot from the screw hole in the “U” retainer to the edge so they can be removed without taking the screws clear out. The skewer idea is the ultimate though.

The frame is done … talk about rapid prototyping. There’s quit a bit of machine work to do after the parts were cut on the water jet but it went pretty fast. The water jet part was REALLY fast - the crown blank took 8 minutes to cut and both legs took 11 minutes! I’ve posted some more photos in gallery.

Now it’s time to make a ridable MUni out of it and go for a spin …


Won’t these bearing holders have the same problem as the lollypops?
The schrew/U-retainer interface will take some of the force when you use it, and eventually it will fail.

Re: New bearing holder idea

Go ahead and blow. It IS a cool idea. Now all you have to do is convince the foreman that you’ve made a couple of connecting rods for a steam locomotive.

It’s amazing that the water doesn’t wear out. Tough stuff!

Very nice idea. I always thought one of the weaknesses of your either frame design was that you have to remove a leg to remove the wheel. This would solve that problem with out compromising the look of your frames.

So… is that waterjet thing going to be carving out some adjustable cranks anytime soon?


I want your job, SHoward…:frowning: I wish I had a job as cool as yours.

Absolutly amazing. Not only are your uni’s a work of art, the ideas are great. It’s things like this that push unicycle technology to the next level. I really like the idea of a quick release. Not that I’ve ever had a flat on the trail, it sure would make things easier. Keep up the good work.

I just wanted to let you know that i REALLY like the design of the forks, and the bearing holders. What’s the material it’s made out of? Also, i was just wondering if you think the bearing holder will hold the bearing firmly after it starts getting used. Seems like the inability to tighten the bearing cap could also be a disadvantage, but i really hope not, because this design looks to be so much easier and quicker to assemble/disassemble! Great Job!!!


What will you think of next!

A proper machined bearing holder that cannot be over tightened. I love it. It’s amazing how many main cap bearing holders are too tight. I’d be willing to bet that 99.9% of all black Torkers available at bike shops have their bearing holders too tight. Most unicyclists also tighten the bearing caps too tight. A bearing holder design that is idiot proof definitely is needed.

The Water Jet Muni has been assembled and ridden but I wouldn’t say it was a “brilliant” success …

The water jet machine cuts hard material such as steel or aluminum with a combination of high pressure water and abrasive (red garnet usually). The orifice that the water passes through is either ruby or diamond. We got two spare ruby and one diamond with the machine. Right now I don’t know what the difference between them is except the diamond is more expensive. The “mixing tube” is where the abrasive is injected into the water stream. It’s made out of tungsten carbide. Soft stuff like diapers are cut with water only … much gentler on the baby.

Back to the MUni …

I robbed the wheel setup out of my current MUni but had problems right away. The “U” retainers are pretty wide and the hub flanges on this particular wheel are wide too, so the spokes rubbed slightly on the “U” retainers. The hub is a Profile copy that I made. I made new spacers to widen out the bearings slightly, then had to spring the fork legs out a little to match the wider bearing spacing. The “U” retainers just clear the spokes now. Not ideal but it works. The rest of the assembly went fine.

I went to a trail that’s down on the valley floor - there’s still lots of snow everywhere else. I took off and right away could feel a little “clunk” when I pedaled. I rode for a mile or so then stopped to see what was happening. The bearings were slightly loose in the holders. Evidently I didn’t get the holes for the screws positioned well enough and the “U” retainer wasn’t holding the bearing snug against the bottom of the fork leg. I took the “U” retainers off so I could shim the bearings with some paper or something but I didn’t have anything with me to use as a shim. I was out in the lava rock and sage brush so I peeled a little sage brush bark off and used that as a shim. Worked good! The rest of the ride was fine with no clunking or looseness. I guess I just miss-drilled the holes.

From this prototype I’ve learned that even though the water jet does an amazing job of cutting aluminum the finish isn’t something you really want to end up with. It would be better to rough cut the stuff on the water jet but still take a clean-up cut on a CNC mill so all the surfaces are smooth and true. I’ve also learned that for this style bearing holder to work well it should be narrower and made with precision.


Diamonds are forever

i like what i see under the seat :wink: :wink:

I love the idea of a quick-release bearing holder…great thinking! Steve, can we expect to see one of these any time soonish?