Tip for using Roborest

[rkriet]

I have a Roborest that I use for sharpening my scrapers. I have found that, if I use the small shaft that comes with the Roborest to set the desired angle, there is quite a lot of play in the jig. To remedy this, I use two small drill bits that are exactly the size of the holes in the jig, and I use these instead of the small shaft that came with the Roborest. I insert one drillbit in each side of the jig. They fit quite snuggly and eliminate virtually all of the play or “slop“ in the Roborest. This modification allows me to get a repeatable and exact grind on my scrapers.

Reed, I would be interested in your thoughts on this idea.

 

[Tom Gall]

I believe that little bit of slop makes no discernible difference in actual use ... especially with scrapers. I prefer the ease of use with the provided hex pin - rather than having to install 2 drill bits.

 

[john lucas]

I found that I simply biased the tool down which takes up the slop. When I changed to the Kodiak rest there isn't any slop at all.

 

[Mark Jundanian]

@rkriet , good idea. What size are the drill bits?

 

[robo hippy]

Trying to remember..... The hex handle is 1/8 inch. I think the tube is 1/64th over that, but not positive. I never noticed any slop till some one commented about it. The piano hinges that are used for the pivot point are not precision machined, and no one makes some thing that precise in that size. I did have to check each one to make sure the pin would slide all the way through, and some would need to be tweaked a bit for the ideal fit. When using the rest, I tend to put pressure on the tail of the platform rather than on the wheel front part. this locks it in. Dave Schweitzer noted that if he put the pin in on one side, it would walk out that side from vibration, but if he put it in from the other side, it didn't. To fix that, he put a bend in the pin. I may have been able to go up one size on the pin for a more 'perfect' fit, but then the problem with making sure the holes lined up on both sides would be worse, and some may have ended up needing to be forced through.

I have been looking at an angled table from Woodpeckers made for the drill press so you can set angles. It has geared/cogged teeth on one side and a cam lock on the other side to set angles, and lock them in for drilling angled holes. That looks like it might be possible to use that idea for another grinder platform, but the inventor side of me knows that other things in life have priority, like fun time.....

I did discover that my angles are off by 5 degrees. Not sure why. So actual 40 degrees is at the 45 mark, and my 70 degree setting I use for my scrapers is actually 65 degrees. That may come from the thickness of the tool being sharpened. So, a 1/4 inch gouge may be slightly more acute than a 5/8 gouge. Not positive.

robo hippy

 

[Randy Anderson]

A non issue for me and I use it every day. I'm not that "precise" in needing things to be exactly 60 deg. I just want consistency so I know what to expect. Since when sharpening I apply downward pressure on the plate it should be the same each time - whether it's 60 deg or 63 deg or 57 deg I don't care. Just the same is all that matters for me. I do think as Robo says the tool thickness does make a difference but again, as long as consistent I don't care and it works great for me.