Anthony, I thought you were kidding ! But you did not ! I tryed this methods and it's incredible !! I used grit 16 (yes very coarse) I got the shape in two passes (just one disk for a 5m rail)!! :D then polished with grit 120 .... yes now it's a painless process, thanks !!!! :)

...and folks looked at me with that "tilted dog head" look when I suggested 36 grit disk backed by a grinder disk to start the profile.
I didn't learn my own lesson until the 2nd machine! The 3rd was all done in about 4 hours for all rail sections.
Great to see you progressing so well.

Sean, I believe you've forgotten more about these machines than I've ever learned.:)

Nah.....just having fun with the rest of the group.
The great part was I was fortunate to really understand Gerald's machine and convince friends/students to build one too.
I had a great time assisting many others constructing this fine machine.

Enjoy!

Grinder skate
 

Thought I would share a picture of my skate. I didn't like how my first two attempts wouldn't 'glide' like I wanted it to, so I made this one with bearings so it would be ultra smooth.

Based on my first experience with cutting rails down, I would like to suggest that a dedicated plate be made for this operation and included in the skate kit. It would essentially be the same as M6 10 115, but without the angled section.

This would save having to make the preliminary cut on the 2.5" side before making the final cut. I would think the increase in cost would be minimal since it requires no additional bending operations.

Looking through all the pictures of the skate I'm now a bit confused....
Cutting the horizontal axis (first cut) is done by shimming up to the required the height with bolts or wood.
The rail height is referenced to the base upon which the rail sits flush to.
Ideally this will produce a parallel cut relative to the flat surface, no problems there.

When the bevel gets cut in, the reference point is the top of the rail, not the base.
I see a problem here as incomplete passes will cause different heights, whereas pre-set depth gauges to the base of the rail should give a more accurate grind???
I haven't made up my skate yet, and maybe this has been discussed before, or perhaps I have missed something but would be interested in others opinions
Cheers
Bazza

When the bevel is being cut, a portion of the top edge, approx. 1/16th of an inch, remains. The bevel is not cut to a sharp point. This flat area becomes the reference for the bevel cutting and ensures the bevel is the same along the length of the rail. A bolt or bearing rides along the top as the bevel is created.

Clayton

Hi Clayton
Thanks for the explanation, I saw some people grinding their rails on youtube When I noticed the backward and forward strokes throughout a run I thought they were creating low-points by doing so
Cheers
Bazzwaldo

Bazza

Just finished my rails and it is pretty close end to end on all of them. The backward and forward motion you are seeing on youtube is so the grinder doesn't bog down. When you set a "depth" on the skate it will grind/sand the angle down to that limit over the entire length of the rail, taking small bites as you move down it (as per the videos). It will effectively stop sanding/grinding stuff off when the steel gets to the level of the setting on the skate.

One tip I can give you is take it slowly with the Vee, grind/sand one side at a particular depth and then switch to the other side with the same setting so the vee is even. Sneak up on the 1mm flat at the top slowly as it will suddenly get close without you realising it. Use 24 0r 36 grit sanding discs backed by a 2mm flat grinding disk to do the vees, much faster than grinding. As you get close, change to an 80 or above for a smooth finish.

Cheers
Bruce