VexPro Bearings

[Michael Corsetto]

Originally Posted by kbrowncny

You mentioned getting the fit right is important when you turn down hex stock to use thunder hex bearings (13.775mm round). When using the thunder hex stock are there any tips and tricks to get the right diametrical clearance, understanding the oversizing from the manufacturer? When working on the lathe and a 3 jaw chuck we had to try a few times and experiment to get the fit a "slight press fit". As soon as the tool started removing material from the part was too much to get a press fit. We also tried a live center to keep it straight. It took a couple times and some scrap material to finally get it right. When we were able to turn down the shaft to achieve the correct fit the cuts were still inconsistent. This may have to do with the lack of eccentricity of the part vice thunder hex stock, I'm not sure how to get it perfect. It is unfortunate that the thunder hex stock still requires precision machining to get the "slight press fit". This burned a lot of our manufacturing time this year.

Did you try using some emery cloth instead of a cutting tool to take off the necessary material?

We've done that for all of our thunderhex this year and it just takes a few seconds. You could even chuck the thunderhex in a drill press, mill or hand drill and take off the necessary material with emery cloth, no lathe required.

-Mike

[Brian Selle]

Originally Posted by Michael Corsetto

Did you try using some emery cloth instead of a cutting tool to take off the necessary material?

We've done that for all of our thunderhex this year and it just takes a few seconds. You could even chuck the thunderhex in a drill press, mill or hand drill and take off the necessary material with emery cloth, no lathe required.

-Mike

This. Since you are only taking off a couple 0.0001's of an inch you won't be able to hold that tolerance cutting unless you have a really nice lathe. We sand the thunderhex stock on the lathe with emory cloth until the axle turns a certain shade of silver and get very consistent results.

[kbrowncny]

Have not tried Emory cloth to get the shaft to the right diameter. Seems like that might work better. Will give that a shot for the next few. The drive axles are made from steel hex so our only real option was to use a lathe and cutting tool to get the 13.75mm.

[RoboChair]

Emery cloth, the original finished to fit option for machinists of old. "Oh, it doesn't fit?" "Just work down the high spots a tad"

[Paul Copioli]

The Emory cloth is absolutely the way to go. Basically, we take off the anodizing on the round part of the thunderhex and it is a nice slip fit.

However, right now since the thunderhex is slightly oversized it is the perfect size for a press fit. We use our small arbor press to get the shaft in the bearings.

With that said, the Thunderhex used with thunderhex bearings is supposed to be a nice slip fit. The bearings are completely within our expected tolerance but the thunderhex stock is a few 10 thousandths large. This is large enough to make it a slight press fit. It is so close that when it is about 30-35 degrees here in Texas the shafts are a slip fit!

In any case, once we run out of the current inventory we will make sure the next batch is within our size requirements at 75deg F.

Paul

[Jon Stratis]

Originally Posted by Paul Copioli

The Emory cloth is absolutely the way to go. Basically, we take off the anodizing on the round part of the thunderhex and it is a nice slip fit.

However, right now since the thunderhex is slightly oversized it is the perfect size for a press fit. We use our small arbor press to get the shaft in the bearings.

With that said, the Thunderhex used with thunderhex bearings is supposed to be a nice slip fit. The bearings are completely within our expected tolerance but the thunderhex stock is a few 10 thousandths large. This is large enough to make it a slight press fit. It is so close that when it is about 30-35 degrees here in Texas the shafts are a slip fit!

In any case, once we run out of the current inventory we will make sure the next batch is within our size requirements at 75deg F.

Paul

So... you're saying I just need to toss my shaft in the snow for a few minutes and it'll fit. Hmm, I wonder where I'll find that around here

[cbale2000]

Originally Posted by Paul Copioli

With that said, the Thunderhex used with thunderhex bearings is supposed to be a nice slip fit. The bearings are completely within our expected tolerance but the thunderhex stock is a few 10 thousandths large. This is large enough to make it a slight press fit. It is so close that when it is about 30-35 degrees here in Texas the shafts are a slip fit!

In any case, once we run out of the current inventory we will make sure the next batch is within our size requirements at 75deg F.

Paul

Interesting, I'll have to remember this. Ain't thermodynamics great?