Surface Grinder Attachment

This last weekend in the shop was spent tooling up my setup.  I've been making folders for several years now and have always struggled with grinding parts flat at a consistent thickness.  Until now, I have used the flat platen on my belt grinder to get things close, then finish off on the disk grinder or by hand on my surface plate.  As you can imagine, it takes a lot of work to get a part to thickness and the pain of burnt fingers has ever been part of the process.  Plus, my tolerances have room for improvement.

For some time now I've researched and watched Ebay for available surface grinders with longing. Unfortunately, I've never been able to justify the cost of adding a surface grinder to my equipment arsenal.  Not to mention that I really don't have anywhere to put a surface grinder, even if I could come up with the cash to purchase one.  A couple months ago I ran across an interesting video on Youtube of a shop-made surface grinder that the guy built and attached to his belt grinder.  I've been intrigued with the idea ever since, and this last weekend I decided to give it a try.  Here is what I came up with.

The attachment simply bolts onto my 6" contact wheel tool bar.  The concept is fairly simple.  A rectangular frame pivots forward and back perpendicular to the wheel surface.  The depth or thickness adjustment is made by a piece of threaded rod located near the bottom of the frame. Everything is bolted together since I don't have a welder, but it's built quite solid.

In the center of the frame is mounted a heavy duty drawer glide with a section of a welding magnet attached to the glide with JB Weld.

The grinder attachment is operated by extending the glide upward, moving the magnetic sled across the surface of the contact wheel.

By moving the sled back and forth across the wheel and advancing the threaded rod, which moves the whole assembly forward, the surface of the piece is ground down a tiny bit at a time until the desired thickness is attained.

In spite of the small amount of play in the drawer glide setup, I was able to grind a piece of 1-1/2" x 5" piece of steel down to thickness within a 0.0025" tolerance.  That's so much better than what I can get by hand, and the time required was reduced by at least ten fold.  Another benefit was no burnt fingers!

I was quite pleased with how this little gadget performed.  I have several ideas to improve the setup which I will likely implement in the near future.  Chief among those improvements will be to replace the draw glide with a sled on bearings.  Eliminating the slop in the draw glide should greatly improve the accuracy of the tool.  A handle is a definite requirement for the sled, and a knob will be attached to the threaded rod for more comfortable control.  I think that this prototype proved the concept is sound.  Now to make a few tweaks to make it better.  I love it when a plan comes together.

-  Brandant Robinson