Disc grinder attachment for belt grinder

[Bryant Hollinger]

Anybody have one of these? I want a disc grinder, actually would like two a vertical and a horizontal. This with my variable speed grinder and flipping plates would solve that problem.

 

[Bryant Hollinger]

https://blackfoxknifeworks.com/knifegrinder/9-disk-sander-attachment

 

[Dominick Maone]

One of these was for sale here a few days ago. https://www.bladeforums.com/threads/black-fox-9-disc-grinder.1710961/

 

[Ken H>]

For the $420 shipped price of that attachment you can have an actual variable speed disk grinder. I built a disk grinder attachment to use with my variable speed 2X72 but never used it all that much due to the hassle of switching back 'n forth. Based on that I decided a disk grinder wasn't something I'd use much. Finally somebody convinced me there were worthwhile, so I build one.

Order a 1800 rpm 3 ph motor , $135 shipped for 3/4hp, $165 for 1hp
Order a chinese VFD for $80, https://www.ebay.com/itm/141396652754? Order that VFD, not necessarily from that vendor. I've got 3 of them running now and they're especially easy to setup with a good ENGLISH manual with clear easy to follow ENGLISH instructions.

Order a decent flat disk $85: https://trugrit.com/product/9-billet-disc-with-5-8-arbor-flat/ (and other places)
Order a stand from HF for $40 shipped: https://www.harborfreight.com/universal-bench-grinder-stand-3184.html

Bolt it all together and you've got a decent disk grinder for $375. You still need a tool rest, but the attachment doesn't have that either.

 

[Killgore]

That does seem awfully expensive. I would not use a disc grinder that you can't reverse. So, if you can't reverse your grinder, don't do it. Reversible VFD is basically a necessity for disc grinders, IMO.

Now, if you had no room for another machine and you can reverse your belt grinder, I could see it being an alternative. I'd still say go with a dedicated machine if at all possible.