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Forum topic by forexpipz posted 12-01-2011 08:13 PM 3175 views 0 times favorited 4 replies Add to Favorites Watch
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forexpipz

4 posts in 1833 days


12-01-2011 08:13 PM

Hello everyone. My first post so here goes.

I have a 2000 watt 230mm grinder and have modified it as follows:

1 With the grinder still in the plastic box I have cut an opening where the grinding disc is situated. This allows the disc to protrude approximately 2.5 ” outside of the box when the box is placed on a plane surface.

2 I have adhered using spray adhesive some Norton Extreme Green 120 grit sandpaper to both sides of a 3mm by 230mm grinding disc.

3 Cut holes in the box to prevent overheating.

Today I attempted my first grinding session with a few old chisels. Basically I placed some heavy 1” thick plywood parallel to the blade with lets say a 1mm gap. On top of the plywood I have a granite tile upon which my Richard Kell Number 3 mark 2 honing guide rides. I set the projection and proceeded to grind.

At first it was as scary as HELL. I pictured flying shards of disc in my head and imminent images of decapitation at the neck. This feeling soon disappeared when I realized that with very faint touches and coordinated control the Kell guide actually takes most of the decisions literally out of your hands and you are just thinking about lowering the blade onto the disc.

I plan to post some images and perhaps a video of this set-up in operation. At the moment the only downfall I can see is the noise of the grinder and perhaps the shattering of the disc which I think is unlikely given that the paper is adhered to both sides and the item being sharpened is only lightly placed upon it. Fingers cannot e trapped because the disc is fully co-planar with the plywood. Perhaps a overhead plastic guard would make this setup bulletproof. Also note that everything is clamped down.

Please advise me on any issues that may arise. So far heat build up as been virtually nothing. Warm to the touch. It seems the large plate on the Kell guide acts as a very capable heat sink. The motor never stresses and you can either touch down the chisel or plane iron anywhere on the disc or you can ride the guide back and forth. I have been using a combination of the two but I seem to prefer just touching down. Its very fast and very effective and seems to provide more control. Your comments would be greatly appreciated.

Cheers.

Marc. (uk).


4 replies so far

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forexpipz

4 posts in 1833 days


#1 posted 12-01-2011 11:01 PM

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forexpipz

4 posts in 1833 days


#2 posted 12-01-2011 11:27 PM

Got a little giddy and posted a few pics.

The part where the granite meets with the grinding disc needs an arc cutting into it so my fingers don’t wander off down the tunnel of decapitation.

The grinder vibrates a lot but once a ballast is placed inside the box there is no movement. It fits snugly in its moulded case. Its actually very smooth and the grinding disc spins with what seems to be enough stiffness to accurately grind the primary bevel.

I will admit that this scared the Johnson off of me when I first tried it. The grinder just feels too beastly and you have an overwhelming sense of power and overkill but at this moment in time this is my only option because of a lack of funds. I have had to be a little creative with what I have got laying around.

The great thing about this is you just buy a pack of abrasives of varying grits and glue them to one of many grinder wheels and you are ready to go.

You can have different grits on either side of the wheel. When the grits wear you simply apply another one atop of the old one. Job done. Simple – no nonsense and hassle free.

When you get a build up of paper you can simply rip them all off in one go.

Here is a cool feature of the grinder. Say you are grinding at 80 grit and you want to grind at say 120 grit. Its just a simple case of closing the box flipping the box over and viola. Instant grit change. Simple and effective.

That is until someone tells me that the science is out and my metal is going to turn into marshmallow.

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404 - Not Found

2544 posts in 2434 days


#3 posted 12-02-2011 10:43 PM

Wow! you should have added the word EXTREME in the title of your thread. I’m not sure I’d use this sharpening method for several reasons, my sense of self preservation being at number 1.
There’s much debate on here about sharpening, the number crunchers will tell you that buying a stone works out cheaper in the long run than buying abrasives in dribs and drabs. You can pick up a four sided diamond whetstone set for about £20 which will give you good results, there’s less chance of losing an eye or a finger too.
It might not be so crazy if you had a proper way of cramping the grinder body down securely – instead of relying on ballast (that bit is so funny) – and if you added a speed regulator and some guards.
What kind of temperature does the steel reach during sharpening? I’d be concerned about this process messing with the temper too.

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forexpipz

4 posts in 1833 days


#4 posted 12-03-2011 01:27 AM

With the box closed I clamped it to the table today and it was as solid as a rock. With the additional ballast you would have to hit it with a sledgehammer to budge it.

The temper issue was better than expected. If you touch down the guide as opposed to riding it back and forth the heat never reaches warm let alone hot. I think the large plate on the Kell guide acts as a competent heat sink.

The results were very accurate and surprisingly quick.

As for the safety issue I have resolved most of that today. Basically the grinding wheel is completely surrounded by plywood on the same plane. The only thing left is to implement an overhead perspex guard and bobs your uncle. Worst case scenario is a burn if i touch down a finger or two.

I thought about reducing speed but when I actually grind on this thing its incredibly easy and produces minimal heat build up on 120 grit. Touching down with the Kell guide is simplicity at its finest and pretty much guarantees accuracy straight out of the box.

I know it probably would work out more expensive in the long run but for the speed and simplicity its hard to argue with the results.

I turned a knackered chipped 30 degree primary chisel into a flawless (at least from the naked eye) 25 degree grind in about 4 minutes and that was just experimenting with the different methods and places on the disc. On for a few seconds off for 10 – 15 seconds whilst i inspected the results. Also this was my first ever attempt at grinding. To be honest I will credit everything to the Kell guide. Even a monkey like me is able to get spectacular results with virtually no effort on my part. The guide literally takes care of everything.

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