A Project Quest

[John Hasler]

I am an amateur, but please don't let that stop you, I will just have to catch up.

"Amateur" just means that you do it because you like it and don't try to make a living from it. You can be both an amateur and an expert.

 

[Bill Gruby]

Let's stop with the what we are. It is the intent, with the help of this build, to show that all of you, regardless of experience, have the capability to build this Grinder. If that capability is hidden, then Mark and I, with the help of the other pros, will help you find it. Case closed.

"Bill & Mark"

 

[john.oliver35]

Double Row Angular in the noes and Single Row Angular at the rear. The bearings I am sending you Mark, all have a 1.000 Bore.

Let's briefly talk about Preload and why it's needed. The preload on the bearings is to minimize shaft deflection under load. It will be extremely minimal if we go with the Double Row bearing up front. Before someone jumps in with a comment about no deflection will occur, it is always there. There are only two was to minimize it, one use a specifically designed bearing. Too expensive. Two use preload.

"Bill"

Bill - Do you have the part numbers of the bearings you selected? I'd love to see what you chose.

 

[Bill Gruby]

I have bearings here of all types. The Angular Contact Bearings Mark wants are as follows:

Double Row ---- NDH 5205

Single Row ---- NDH 20205

You will have to cross match another manufacturer for their number as NDH no longer makes bearings. They closed the doors of the major bearing plant on January 21, 1995. All different sizes went home with me. LOL

"Bill"

 

[f350ca]

Will the matched pair compensate for thermal changes? The spring loaded single row do a great job of that.
If you go with the matched set at the wheel end of the spindle would you not be better with a regular deep groove bearing on the pulley end and let it float to compensate for thermal expansion.
Can you load a single angular contact bearing against a double set?

Greg

 

[extropic]

The 5205 bearings a double row angular contact bearing. The preload is factory set.

The 20205 is a single row spherical roller bearing also called a barrel roller bearing.
From Wikipedia: snip "Most spherical roller bearings are designed with two rows of rollers, allowing them to take very heavy radial loads and heavy axial loads.
There are also designs with one row of rollers, suitable for lower radial loads and virtually no axial load.
These are also called "barrel roller bearings" or "Tonnenlager" and are typically available in the 202- and 203-series."

Both bearings are metric series with 25mm bores.

 

[ome]

Bill,

First question: Do we want to get these couplings now ? we can make the spindle end 3/4" for mounting.

Second Question: Do we want to make a standard grinding spindle with a taper on the end to mount the arbor or make the spindle all one piece and machine the end for the wheel?

If we make the taper then we could make an arbor with balance weights on the rear. And seeing the price of a ready made arbor.........I say we can make the arbor and the balance system.

This is a representation of a simple arbor with no balance system.



This is a representation of an arbor with a shroud to cover the spindle nose to keep crap out.


This is a representation of one with a balance weight groove.......This one gets my vote


The other option is to machine the end of the spindle to accept a wheel. Simpler but no balance feature.

ANYONE GOT ANY OPINIONS HERE?

I say we go with the balanced weight groove.

 

[ome]

What did we decide on the bearings? I know there won't be much axial load on the spindle but can't we just over-design it. Matched pairs or angular contact bearings? Is there a downside?
As a point of discussion- when would you want to use ceramic bearings? I see them on eBay now cheap.
R

I would go for the matched pairs of double row angular , if that is practical

 

[ome]

Actually , I don't think so. The labyrinth seal is A small gap and there are several grooves in a row. The oil provides a seal between the housing and the shaft between the grooves. they are very good at keeping junk out with no resistance turning. On a 3450 rpm shaft you need the rubber seals with springs and they put extra pressure on the shaft creating more heat.They are both good seal systems. I have used both on projects and they both work good. I can tell the difference turning the shaft with the rubber seal, it adds a good bit of resistance. another option is an o ring in the end cap that is the same ID as the shaft. this has less resistance.

I like the idea of an "O" ring.

 

[Bill Gruby]

Bore size on both bearings is .9843 .

"Bill"