Lapping chisel and plane blade backs - a few tips

[rsser]

Yep. Welcome

If you've got a number of other blades to do and they're likely as hard then heavy duty hardware is called for.

Otherwise it's cheaper to go Scary Sharp and grind away the dropped off corners.

Other/otherwise see if the IBC/Pinnacle replacement blades have been lapped; might be cheaper if you only need a couple (the 2 Hocks I have weren't). Dunno whether TS's blades will come lapped.

[Horaldic]

Ern,

I'll try and get an extra extra course some time over the next three days and will report back.

[rsser]

Thanks.

I think I'm now close to finished with all mine.

In time, 2 of Thumbsucker's fine plane blades will arrive and prob. need lapping. Those are hard steel alloy I believe and will take some effort but I'll aim to do them with the coarse diamond plates that I have. Or maybe I'll crack the problem of cleaning the Tormek wheel side and leave it flat.

Re which by way of digression, I found it's not a no-volt switch so I can wire it up through my inline router on/off switch, blutak something to the recessed on switch and turn it on with my knee with the blade already against the wheel side.

Returning to earlier ideas, on reflection, just for lapping, the idea of a jeweller's lap in a drill press or lathe is one I dismissed too readily. With the coarsest diamond paste it might work v. well. I sourced a 2nd hand cast iron lapping plate from Aussie Sapphire, the natural choice in gemstones.

[Horaldic]

G'Day,

Seems the usual stockists don't import the extra extra course 8" stones. A bit of internet surfing and a few phone calls resulted in a blank and some confusion over the "extra extra" part.

Anyway, the long and short of it is I have placed an order, I'm expecting it to take a week or two.

[rsser]

Ah well, bit late, but it seems Jim Davey does in Diasharp 8x3

Jim Davey - Planes and Sharpening - DIAMOND PLATES: DMT & DIASHARP Diamond Plates for Sale

[Groggy]

Gents, for what it is worth, I have the 10" extra course diamond stones and the Veritas lapping plate and diamond paste. I'd rather use the lapping plate than the diamond stone, I have found they wear rather quickly.

[rsser]

Thanks for the tip Greg.

What micron diamond paste are you using? From where?

Edit, oh, and what are you lapping?

[Groggy]

What micron diamond paste are you using? From where?

Edit, oh, and what are you lapping?

I have a kit of lapping grits that is mixed with oil (not paste, sorry). They came from CT at the T&WWW show a few years ago.

I've lapped normal blades, D2 plane blades, SS blades, plain steel chisels and Japanes chisels plus some other stuff I've probably forgotten about.

If you want to try it out feel free to drop around with something to flatten, you can try both and see what you think.

The lapping plate is only to get things flat, from there you use stones to polish them up.

[rsser]

Thanks Greg. Maybe when TS 2nd blade order arrives.

Just a footnote to an early post in this thread about protecting your fingers, WW has posted another option. Click.

[rsser]

And a bit OT but reading thru DMT guff there's a suggestion that for flattening waterstones anything finer than Extra coarse might suffer damage.

[Mr Brush]

Ern - while I was in McJings (Sydney) last week I noticed that they have syringes of diamond paste in a range of grits. Might be a cheap way of getting a few to try?

I was too overwhelmed by all the exciting toys on offer at McJings to notice the price, but they are probably cheaper than most.

As an aside, McJings webpage doesn't really do the physical store justice. Certainly a happy hunting ground for woodies.....

[rsser]

Thanks for the tip Mr B.

Actually I sourced a bunch from ebay from the US a while ago - for experiments in power honing turning tools.

For lapping with the goo I'd need a flat surface. Groggy's Veritas plate is around $130 from Carba-tec which is a bit steep. V. also used to retail a glass lapping plate but I don't know what the tolerances were.

[Mr Brush]

Just an idea - I keep a box of the old 3M overhead projector films handy for things like this. They are an A4 sized piece of mylar, with quite a hard surface, and perfectly flat. Also, since the advent of the digital age, pretty much redundant. Can't remember the last time I saw someone doing a presentation on an overhead projector. Even better are the 3M Transparency Film for Inkjet Printers (product code CG3700), as they are a bit thicker.

Place one on a flat steel surface (tablesaw, jointer, etc.) - a quick squirt of WD40 on the metal will give enough stiction to hold the mylar sheet firmly. Place abrasive grit or diamond paste on the mylar film, and hone away to your heart's content.

Point is, the OHP films are cheap enough to throw away after every use, or keep one for each grit to prevent cross-contamination.

[Mr Brush]

I forgot - Carbatec list a relatively cheap Granite Surface Plate, ideal for use with the mylar films I was talking about. Guaranteed flat to within a fraction of a gnat's tackle.....

Trouble is, in Sydney at least, they STILL don't have them

[rsser]

OHP film is a nifty idea.

In fact V. used to sell a lapping kit of glass plate and sil. carbide grits with a rec'n that you use Mylar film to hold the grits.

I'm still not sure though whether this set up gets around the differential abrasion that Scary Sharp produces.

Anyway, I'll check out the granite plate. A fraction of a gnat's tackle sounds within tolerance ;-}