WIP Steel grinder disk machining

bladsmth said:
No, that isn't a vertical arbor, that is a horizontal buffer arbor or a jack shaft. It is for running buffers or wheels that give force perpendicular to the shaft. You would want a shaft with bearings to allow thrust parallel to the shaft end ( from the end).

Look at this page and find the AR-16R and AR-17R faceting machine arbors. That is the type made to run a disc or lap that will receive a downward force. The AR-110 and AR-120 are smooth shaft, which is what would work for a disc like Nathan's. I would have to check the bearings they use to see if they are heavy enough for a big steel disc, but this is the type of setup you want to do a VS disc right.
http://www.lapidarydiscount.com/Arbors.html

All that said, 95% of all discs are directly mounted on the motor shaft. From an engineering standpoint it isn't perfect, but form a practical home shop point of view it make good sense.
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Will a belt drive introduce any vibration as opposed to direct drive. I have a 3 phase 1 hp motor that could be used but it has a 7/8" shaft.

Also, any disadvantages to the 1degree disc, anything it can't do that a flat disc will?

Thanks Mark
 
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12345678910 said:
What's the cake pan for ?
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I keep that disk charged with lapping compound and to keep it from getting contaminated with steel dust and handle material, I put that spring form pan with a hair net on it when not in use. You just pop that buckel and the ring pops off the base is bolted to the motor
IMG-20130922-00017.jpgIMG-20130922-00018.jpgIMG-20130922-00019.jpg
 
carbonsteel928 said:
Nathan, or whomever can contribute, what would be the ideal setup for this disk in order to achieve its maximum potential and reduce the chance for runout? From what has been posted, removing the motor and using an arbor such as the AR17 that Bladsmth posted, would decrease/ eliminate runout. But, how would one set up the motor and arbor? Are there any examples (pictures) of the ideal setup for those of us who are not as "mechanically," inclined.

I know this is asking for a lot but after attempting quite a few google searches, I've come empty handed and thought it more prudent to ask a real machinist anyway. :) Thanks in advance.
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The "spindle" (and I'm using the term loosely here) on an electric motor has very little in common with a machine tool spindle. They're both round and they both rotate...

Many electric motors have a bearing on one end and a bushing on the other end creating radial end play. They lack matched radial groove bearings or even a decent thrust bearing so they also have axial end play which is frequently taken up with some kind of spring washer. The length to diameter ratio between bearings is not real good. The "spinde" surface is sometimes not machined or even particularly round. If they have bearings, they're frequently ungraded and without preload.

A machine tool spindle has precision or ultra precision (ABEC 5 or ABEC 7) matched radial ball bearings with a specific amount of preload between them on the working end of the spindle. The spindle is long enough and large enough for stability. The bearing on the end opposite the working end is floating to accommodate small changes in length as the spindle warms up. This is probably overkill for a disk grinder, but if you want an industrial quality setup, that's probably what it will look like. http://www.ebay.com/itm/7x7x17-Prec...9?pt=BI_Tool_Work_Holding&hash=item3f119b3f1f



A good motor such as a high end Baldor or Leeson may have ABEC 3 grade bearings and is dynamically balanced. At a minimum I would recommend a quality motor for any grinding application. I expect this will be good for most needs.

This application is low speed and low force which does not demand much from the spindle.



Right now I have mine mounted on the output shaft of a good quality geared speed reducer which is much less wobbly than any motor I have. I have a set of nice Borg Warner 3/4" pillow block bearings that I plan to use to fabricate a spindle setup using some precision Thomson linear shafting. This is nowhere near a precision spindle, but it is all I need.
 
Nathan the Machinist said:
Right now I have mine mounted on the output shaft of a good quality geared speed reducer which is much less wobbly than any motor I have. I have a set of nice Borg Warner 3/4" pillow block bearings that I plan to use to fabricate a spindle setup using some precision Thomson linear shafting. This is nowhere near a precision spindle, but it is all I need.
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When you finish this setup, could you post up some details. I'd like to get a better idea of how it all looks. Thanks
 
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