Steel grinding disks

Nathan the Machinist

KnifeMaker / Machinist / Evil Genius
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This is an old sale thread that sold out. Please come to the new sale thread located here: http://www.bladeforums.com/forums/sh...grinding-disks

These are 9" grinding disks made of hardened alloy steel (4130 HRC 44), turned in a way to minimize runout and then balanced. They were made by request in response for a need for industrial quality grinding disks made for professional use.

These are time consuming to make. I only have 4 of each ready today. If they sell out, please come back to this sub forum next Saturday and I'll have more ready for sale then.

These are some of the first to be finished out of a batch of 100 disks. When the batch is finished there will be no more of these.

25.jpg~original


26.jpg~original


27.jpg~original


The last thing I do is spin it up on an unmounted motor and let it coast down. The motor is unrestrained so any vibration or other troubles would have an opportunity to show up here. Video if you're curious:

[video=youtube_share;-b_h7NaZxKg]http://youtu.be/-b_h7NaZxKg[/video]

The manufacturing of these disks was documented on this WIP thread:

http://www.bladeforums.com/forums/showthread.php/1088181

These disks are 8.875" in diameter and mount to a 5/8" shaft. Setscrews are included as is some keystock. The key stock may require some slight fitting etc (you're a knife maker right?)

It is important you tighten the two setscrews properly. This disk weighs over 7 pounds, you want it to stay on the shaft. The setscrews are high quality Holo Krome brand fasteners of domestic origin, the sockets will not easily strip. You should use a hex insert in a screw driver rather than a dinky wire Allen Key, and if in doubt use a drop of blue loctite. The thread is 10-32 if you want to change to different screw type.

I have a few 3/4" bore disks in processes, but they're not ready yet.

In this sale I have 4 flat disks and 4 disks with a 1 degree taper on the face. They are $160 each and shipping is $10 in the USA via USPS priority mail. Be aware that if you're more of a casual user, Beaumont Metal Works has an aluminum disk for half this price.

Important, please read:
If they sell out, please be patient and wait for the next sale, I'm not going to run out any time real soon. The balancing process is somewhat time consuming so I am only finishing a few disks every day. I'll try to post a few disks for sale here on Saturdays. I can not take prepayment for an item not ready to ship. Please keep sales in the sale threads to help me keep up with it. Those of you who have bought platens and chillers know how these sales work, but here is how to order a disk:

I need you to please follow these instructions to help me keep up with everything (otherwise folks will fall through the cracks).

1: State your claim in this thread.

2: send me an email (not a private message) carothersknives at gmail dought com

The email should include what you are buying, your BladeForums handle (i.e.: "Nathan the Machinist"), your actual name, your shipping address and your paypal email address.

I will send a PayPal invoice to that email.

3. Pay the paypal invoice. Once it is paid, I will ship your order to the name and address you gave in your order email.

If you don't want to use paypal, we can arrange to send a check.

If there are shortages it will be based upon first come first serve who posts in this thread. I have to do it this way to keep things sane.



Thoughts about "runout":

The manufacturing approach I'm using virtually eliminates runout in the disk because the OD, working face and the internal diameter of the bore are all single point turned in the same setup on a CNC turning center. Unlike drilling and reaming, which can create an off center hole, single point boring creates an accurate hole without risk of bias or walking. Cutting the face at the same time sets the working surface perfectly perpendicular to that bore and cutting the OD at the same time also sets that feature perfectly concentric to that bore. Observable runout on the actual disk is almost physically impossible. That said, you could have the most perfect disk in the world, but if it isn't mounted to your spindle properly or if your spindle itself has runout it is still going to wobble. Electric motors are not ultra high precision spindles, they're simply designed to turn pulleys etc without a lot of fuss. Some even have bushings instead of bearings. If you get a disk and it wobbles I can almost certainly guaranty the problem isn't the disk, but I will still gladly refund your money if you will return the disk in prefect condition.


Thanks,
Nathan
 
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I'll take a flat one please, email incoming

Look like out of flats, I'll take a 1 degree. Instead
 
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I just got mine in the mail. Beautiful work and it has a really nice tone when you ping it. Almost spot on E5 (E one octave above middle C.) :D
 
I just got mine in the mail. Beautiful work and it has a really nice tone when you ping it. Almost spot on E5 (E one octave above middle C.) :D

You got a tapered one, they have a nice ring to them. The other type sounds a little flat.:D
 
Flat are sold out. There is one taper remaining.

I will have a few more ready for a sale next Saturday.

Thanks,
Nathan
 
These are sold out. Lazlo got the last one. Please come by next Saturday and I'll have some more ready.

Thanks,
Nathan
 
Nathan,

I would like one from the latest batch as well. Just not sure which one to get, taper or flat.

Can I get some people who use either or both types to weigh in with personal experiences and opinions about advantages and disadvantages of one type over the other?
 
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