Bench Sander Blade Grinder

[derekcohen]

Here are a few pictures of my newly-completed Bench Sander Blade Grinder. I built this to repair or re-establish the bevels of chisel and plane blades. It is based on an inexpensive (OK, cheap Chinese copy) Carbatec bench sander ($120 a few weeks ago).

The advantages of this jig are:

1. Firstly, it is cheaper than a Tormek (at 8 times the price).

2. It runs cooler than a Bench Grinder and you have to be a complete Klutz to burn a blade.

3. You can grind a flat bevel as well as a hollow ground bevel, and the set up for either takes a few seconds. To do this all you do is reverse the grind direction (face the blade towards the flat or towards the curve).

4. The 4” wide belt grinds the entire blade evenly (for a more even grind), unlike vertical wheels where you must move the blade across them.

If this set up looks simple, you should know that it is Mark 8! I went through several inspired failures until I pared the whole thing down to the basics above. Total cost was about $9 (for the chromed steel tool rest, which is a drawer handle purchased from Bunnings). One aim was to permit a reproducible grind, another was to enable the belts to be changed easily, and a last was to set up the blade angles quickly. Most of this is self explanatory, but feel free to ask any questions.

In practice it really works extremely well and produces perfectly square and accurate bevels. So far it is only set up for 25 degrees. Don’t forget, this is only to grind the bevel – sharpening is completed on Japanese waterstones.

Regards from Perth

Derek

[bitingmidge]

Thanks Derek!

You've solve about five issues for me, (but I'm only up to version two!) The obvious one is actually the clamp jig, (slapping his forehead incredulously!).

I reckon this is one that will spawn a few imitations,

For all those who haven't tried sharpening on a sander - give it a go, it has to be the easiest thing to do this side of an $800 machine.

Derek, what grits do you use on the belts, and what is clamping the jig on the side?

Cheers,

P

[derekcohen]

Hi P

Thanks for the encouragement.

Firstly, although I have not seen a similar jig for a sander anywhere on the Net or in any mags, the basic idea for using a bar as a tool rest is one I recalled from a USA mag a few years ago. The author escapes me at this moment. His affair was fixed (non-removable) in front of a grinding wheel.

The idea for the blade holder comes from him. My choice was to use some steel ange I had lying around. Cut it up with an angle grinder and drilled-and-tapped for bolts (as can be seen in the picture). Place the blade in the blade holder, tighten the butterfly bolts lightly. Then push the front edge of the holder against the base edge and slide the blade up against the front and side edges of the square (glued to the right hand corner of the base). This will set the blade perfectly square and at the corect projection for the desired grind angle. Mine is only set up (as yet) for 25 degrees.

Regards from Perth

Derek

[Termite]

Bloody ingenuo....ingine..... darn good idea Derek. Not to steal any of your glory at all I must advise that part of your post has triggered an idea for ligning up blades square in the Veritas honing guide. If it works I will do a post with all credit for the idea to you.
BTW I finaly have a LV LA smoother on the way from Canada, should be here next week.

[Rocker]

Derek,

I would like to add my congrats for that brilliant jig. I have been looking for a long time for a way of grinding the primary bevel without going to the expense of a Tormek. I shall be off to Trade Tools tomorrow to look for a sander and to Bunnings for the drawer pull.

I think the idea merits wider circulation, perhaps as an article in Australian Woodworker, or maybe as a tip in FW. You could score another plane from them

I also want to know how the jig is clamped to the sander and what grits to use.

Rocker

[derekcohen]

P and Rocker

The belt grits I have range from 60 (excellent for rough grinding) to 150 - I'm not sure if there are smoother ones available.

The jig is bolted onto the steel frame. I drilled and inserted steel insert threads into Jarrah blocks. These are bolted from the inside. See pic below. There is no need to get obsessional about these being level - it is more important to drill the depth of the guide rest holes accurately, which is easily done on a drill press when the Jarrah bases are attached.

Regards from Perth

Derek

[derekcohen]

Hi Termite

Great minds think alike. I did, in fact, post a pic of a jig I made up for the Veritas guide some time ago. I think this (below) is what you are looking for.

Regards from Perth

Derek

[Termite]

Hi Termite

Great minds think alike. I did, in fact, post a pic of a jig I made up for the Veritas guide some time ago. I think this (below) is what you are looking for.

Regards from Perth

Derek

Yep, thats exactly it! Thanks Derek.

[journeyman Mick]

Good one Derek! It's quite a few steps removed from holding the Makita belt sander upside down with the trigger locked (tricky in itself!) and regrinding a damaged chisel freehand, but I don't feel so guilty about my methods now

Mick

[echnidna]

Bit of thinking about the design and you could set up a planer sharpening attachment.

[numbat]

It is based on an inexpensive (OK, cheap Chinese copy) Carbatec bench sander ($120 a few weeks ago).
Derek

Hi Derek,

Great idea. Just a quick question - what was the bench sander model you used as i cant see anything similar in the cattledog for around that price.

Cheers

[TassieKiwi]

Excellent skills Derek. Wouldn't you be able to change the grinding angle by extending/retracting the tool?

[derekcohen]

what was the bench sander model you used as i cant see anything similar in the cattledog for around that price.

Numbat, the rrp is $169, I believe, but it is (was) on special for $129. The model is in the catalogue.

Wouldn't you be able to change the grinding angle by extending/retracting the tool?

Tassiekiwi, yes - that is how it is done. I will post a picture later to show you more.

Regards from Perth

Derek

[Rocker]

Derek,

Can you tell us how much clearance you have between the lowest point of the drawer pull and the sandpaper. I have got my support blocks mounted, but need to know how deep to drill the holes for the upright parts of the drawer pull. Also, how far from the top (outer) corner of the angle iron are the centres of the holes for the butterfly bolts? Do you think aluminium angle would be strong enough, instead of steel?

I got my sander from Trade Tools, Model RBDS-46A, for $139, and the drawer pull for $7.20 from Bunnings.

Rocker

[TassieKiwi]

THis might be another Duh!, but oculd you thread gutter bolts into the drawer handle for fine adjustment - the heads would rest on the bottom of the holes - to preclude the need for super accuracy in drilling?

BTW this is the best idea I've seen yet - and you've a sander too! Will it take a fence?