How to make an epoxy hub on your grinder wheel

[buttercup]

The epoxy builds a maximum 0,5mm, and yes they do use epoxy and carbon weave to make race car transmission axles.
This particular epoxy have metal particles blended in that gives it especially impact hardness and makes it particularly suitable for metal parts, it also have a higher heat tolerance.
You need to dress the wheel after the operation to make it perfectly balanced - once.
It will have a molded fit to your individual grinder that is a better fit than any mass production is capable of making.

I always use a Kevlar west when dressing my wheels, don't you?

 

[buttercup]

Question ? can minute vibration cause the epoxy to wear...

Definitely not, but if you want to be absolutely sure the epoxy should cure for 24 hours at room temperature to gain its maximum strength.

 

[buttercup]

Oh, I see. No, I've never used a chainsaw grinder. Just lots of angle grinders, bench grinders, etc.

I can see how using a "shaping stone" could make the center bore and outer circumference concentric, yet you could still have imbalance, but I'm guessing a chainsaw grinder doesn't turn fast enough to matter. (I was thinking this grinder went real fast like an angle grinder...) So...never mind! Shoulda kept my mouf shut.

Most of these inductive motors turn at about 3000 rpm, that may be a bench grinder, compressor or similar.
Some rare or special units might have a lower rpm and it would usually be pretty exactly half of that at slightly less than 1500 rpm.

 

[old guy]

Just looked it up, Oregon grinders, depending on model, turn 3400 to 4200 rpm.
The wheels are 1/8'', 3/16'' and 1/4'' thick.

 

[buttercup]

Just looked it up, Oregon grinders, depending on model, turn 3400 to 4200 rpm.
The wheels are 1/8'', 3/16'' and 1/4'' thick.

I wonder why that is, I wanted to make an rpm adjuster to be able to slow down my grinder, not because of unbalance but to reduce the heat and make it more sedate and precisely workable.
I like to have the benefit of time and human influence to get the results I want, most of my other grinding tools have adjustable speed.
Anyway I will probably need to buy a new grinder if the interest around my area is keeping up, and the Oregon 5 or 6 versions is what I'm looking at.
The Stihl is at about the same cost but I just cant see any obvious benefit too it - unless you have a lot of money to spend on all the extra stuff they have made for it.
My own made wice is nice, accurate and slop free but I miss the ability to move/adjust the wise back or forwards to get it perfectly centered below the wheel.

 

[Philbert]

I checked a few grinders. The 5-3/4" diameter (Oregon / Tecomec / clones) were 3,000 to 3,400 RPMs. The smaller, 4-1/2" grinders were 4,000 to 4,800 RPMs.

A while back I mic'd the arbors on several similar, Oregon and Tecomec grinders and found that they varied by several thousandths, so there is wheel variation and grinder variation.

It is also hard (but not impossible) to index these wheels so that they are always mounted in exactly the same rotational position.

Only real problem I had with vibration on chain grinders was with the smaller, HF style grinders: there appeared to be 2, different 'standards' for what '7/8" ID means. An SAE one and a metric 'equivalent'. I could not swap wheels between certain 'similar' grinders.

Philbert

 

[Canyon Angler]

I have some cheapo HFT Chinese angle grinders (with universal, not induction, motors) that apparently have some kind of electronic speed controls (even though they are not adjustable speed) and they seem to go insane fairly regularly, causing the grinder to spin up, then spin down, then spin INSANELY fast, etc etc. And yes, you'd better wear your bulletproof body armor if you use one when it does that because chances are good that the wheel will come unglued!

 

[buttercup]

I have some cheapo HFT Chinese angle grinders (with universal, not induction, motors) that apparently have some kind of electronic speed controls (even though they are not adjustable speed) and they seem to go insane fairly regularly, causing the grinder to spin up, then spin down, then spin INSANELY fast, etc etc. And yes, you'd better wear your bulletproof body armor if you use one when it does that because chances are good that the wheel will come unglued!

Well Chipper1 noted that a chain grinder may not have the power/torque to slow down anyway and I guess that might be true.
I can make a power adjuster to any AC motor and you can get those ready made too, but with an induction motor it would need a load to slow down because the speed is regulated by the AC current frequency.
So I tried to make an rpm adjuster on mine but ended up reducing the power without actually reducing the rpm, and at some point the motor safety switch will turn it off.
Sounds like your angle grinder has a power compensation /governor that don't work properly and I have seen that on some cheapo electric turning tools too.

The wheel can fail like any wheel can, but it wont be because of the epoxy hub because that will only make it better - no matter what quality you are looking at.
Unless your wheel already have a factory made steel hub that have a perfect fit on your grinder axle of course.

 

[buttercup]

I got this in the mail today, made in Italy. It measures 22,25mm inside diameter.
The axle hub on my grinder measures 22,12mm so that's a slightly sloppy fit, no doubt it will be unbalanced and need a new dressing each time its mounted.
I could index it of course, but it would still be a slightly sloppy fit. I wonder what a minute vibration could do to that.
My experience however is that it isn't the axle hub itself that holds it in place - even when unbalanced. It's the hub washer/plate and fastening screw washer that does that.
It probably doesn't hurt though - that the hub has a perfect fit.