A long hard grind (wet too)

[Rattie]

After getting the planer knife jig for the Tormek at the D&M show at the weekend, I decided the other night to sharpen my original HMS260ci knives that came with a slight ding from NMA. I was offered a replacement set once Greg at Mackays in Cambridge had convinved them that I had not chipped them myself, but having seen how unsharp my spare blades were, I decided I would shapen them myself and remove enough stock to lose the ding.

So I read the leaflet, watched the right bit of the video (which I've now got as a WMV file), set up the Tormek and went at it.

Now Tormek owners will know that as you move the tool back and forth, every now and then some water will fall onto the tormek body or spill off beyond the water tray. Well, 260mm blades tend to transfer most of the working water onto the floor and all over the machine in about 5 minutes. At that point, the stone goes dry and you have to fill up again.

I ended up using the tormek in a large plastic tray that we got for cleaning BBQ grilles in, and keeping a car washing sponge at one corner to mop up the water and transfer it back into the trough.

In the end it took my over two hours to grind and hone both knives, reactivating the stone every know and then to keep some kind of progress going. I guess it just shows how tough these knives are compared to most other tools I've sharpened on the tormek, but I was very glad to finish.

The knives are now back on the P/T and adjusted. The finish is really good, and worth the hassle.

I can't help thinking that a secondary trough could be a nice accessory for the Tormek, which would guide water back into the main trough that has made a bid for freedom along long knives.

Martyn

 

[SimonA]

Rattie, I have always wondered if you would get better results grinding a steeper bevel on the blades for those harder timbers or secondary bevel......I've just got the Rexon wet stone grinder and the next time my planer blades need sharpening I think I'll give it a shot........I also think I might try and hone them to a nice mirror finish to see if this helps also, it works for a chisel and plane blade.....why not here?

I have also found myself sharpening my tools a lot more since I bought the wet stone grinder. I just turn it on sharpen the blade in question and I'm off and working again....


SimonA

 

[ike]

it works for a chisel and plane blade.....why not here?

If you think about it, changing the bevel angle on a planer blade (normally 40 degrees) is akin to changing the bevel angle on a bevel down hand plane. You need that angle as a clearance angle to the surface of the timber. The angle to change to reduce tearout is the angle at which the knives are bedded in the cutter block. Therefore grinding a steeper bevel on a planer knife will only result in the knife contacting behind the cutting edge.

 

[ike]

But of course I may have missed something. If so, please shoot me down!

Ike

 

[SimonA]

If thats the case then you could still get away with putting a back bevel on it.....

SimonA

 

[Alf]

If thats the case then you could still get away with putting a back bevel on it.....

As mentioned here and (briefly) here.

Cheers, Alf

 

[ike]

As mentioned here and (briefly) here.

(Bows humbly to the Fount of All Planing Knowledge) :roll:

 

[Aragorn]

Stick at it Rattie
The first time I sharpened planer knives on the Tormek, I thought "Never again". Like you it took about two hours and the water went everywhere. I can now do a badly dinged blade in about 20 minutes and a couple of well positioned sponges solves the water problem.
By the way - there is less water overboard once you get the knack of sharpening a bit better!