floatglass as a surface plate thickness?

[Jacob]

Oh dear I see problems ahead. How will you stop such a long piece from flexing unless you can support it on another more solid flat surface? Daily temperature variations can be quite rapid and cause expansion at the surface. Perhaps keep it stored on end so that the ambient air will reach all sides evenly, on points of course, so that air will reach underneath. And turn it at intervals.
:shock: :lol:

No it's OK really. Overkill, but only a fiver. A piece of mdf would have done.
There is a lot of obsessive nonsense burbled about the flattening topic.
The only important thing is to ask yourself whether or not your plane is performing well. Some people do more flattening/fettling than planing!

 

[bugbear]

There is a lot of obsessive nonsense burbled about the flattening topic.

Some people do make a lot of posts about it...

BugBear

 

[Dangermouse]

I mainly use the granite to restore old planes with some rust on, I don't over do it too much. I like to get a nice clean surface. After all its nicer to use a well restored or mint condition plane than one thats a bit of a dog, :lol: , even if they do work as well as each other, or at least thats my opinion. Being an engineer i'm used to working to fine tolerances. But each to his own.

 

[Benchwayze]

12345678

 

[James C]

I see most guys are using about 10mm thick
floatglass as a surface plate.......

Most (woodworking) guys don't "surface" at all, in my experience. It's a tooly thing!
Personally I use a sheet of wet n dry on my planer bed. Held in place by wetting with white spirit.
Or wet n dry, dry on a thick piece of mdf is good enough for most woodworking tools IMHO.

I'm up for giving this a go. Do you have to have to pour white spirit all over the back of the paper or just work a small amount into it? Or is it better to pour a very small amount onto the table and then smooth the wet n dry over it?

 

[Jacob]

Just splash it onto the table and then onto the paper. It's better if you keep the paper between boards when not in use so that it stays flat. Paper backed, not cloth backed, which doesn't stay down so well

 

[James C]

Do I need a piece of wet n dry the same length as my plane? I want to sort my No7. I have wet n dry belts that fit onto the band sander but I think they must be cloth backed. The only definite paper backed stuff I have is 400 grit so probably too fine.

 

[Eric The Viking]

I haven't tackled my #7 yet!

I wasted a lot of time and elbow grease doing my #4 and #5, simply by not going down the grits properly - starting with too fine a paper. In the latter case I realised I was being an silly person and switched, and the process didn't take too long at all.

In both cases, the soles are now so flat that 'stiction' is a nuisance. I thought corrugated soles were a fad until that point! That said, when they're well lubricated, they will work really nicely.

Was it worth the effort? Dunno. My #4.5 and #7 haven't been flattened. The #4.5 still has the factory honing marks on it (my dad bought it and rarely used it), and the #7 is circa 1920. Both cut really well.

I think we worry too much, unless there are actual faults with the sole, for example hollows in the wrong places or concavity generally.

Being able to sharpen well is a lot more important, and for that 10mm glass pretty much does everything I need.

 

[Jacob]

Any length will do. If it's short you adjust the pressure so its held down as it goes over the paper. As you would when planing. It's obvious when you do it.
Coarse is faster. NB you don't need to progress to finer papers if you keep the abrasion fore and aft lengthways and not across or diagonally (on the sole that is). The sole may look roughly sanded but it will soon lose the sharpness with a bit of use. Or you can accelerate this with a final pass over a fine paper - you only need to take the tops off the scratches, not to polish, it's not like finishing a piece of wood, you don't need the intermediate grades, you don't need to polish.

Corrugated or scratched soles can still be low friction - if the bits in contact with the wood are smooth themselves. You can have flat sole and low friction just using 60 grit alone - as long as you take off the sharpness, with use (and candle wax).

.....
I think we worry too much, unless there are actual faults with the sole, for example hollows in the wrong places or concavity generally. ......

Dead right - don't bother unless your journey is really necessary. Don't polish - completely unnecessary and a huge waste of time.

 

[Jacob]

Re. not polishing. I found this out by chance when I bought a new plane. The sole was flat but machine marked. In use it tended to track along the direction of the machining - which was fore and aft so so didn't matter much. I though I ought to polish it up a bit, but before I got round to it it had stopped tracking and appeared to be smooth even though the machine marks looked unchanged.
The explanation is simple. Scratches, pits, corrugations, whatever, are like ridges and furrows. To reduce friction you don't have to get down to the bottom of the furrows, you just need to take the sharp edges off the tops of the ridges and get them to the same height ("coplanar"). This will happen with use, or you can speed it up with fine paper.
This applies to chisel faces too.
It follows that you can flatten a sole (if you have to) with say 40 grit paper, and then go straight to 200 grit (or finer) to "blunt" it and reduce friction, without going through the grades in between.
All that polishing is pointless.

 

[Eric The Viking]

I beg to differ a bit on chisels: The mirror surface does let you get a better edge. My sharpening is improving, both in speed and quality, but I've only ever managed to get a 'dry shave' edge on chisels I've mirror-polished first.

Obviously, it's a different objective with plane soles.

Cheers,

E.

 

[Jacob]

I beg to differ a bit on chisels: The mirror surface does let you get a better edge. My sharpening is improving, both in speed and quality, but I've only ever managed to get a 'dry shave' edge on chisels I've mirror-polished first.

Obviously, it's a different objective with plane soles.

Cheers,

E.

Well yes it needs to be clean immediately behind a sharp edge - press down a touch when removing the wire edge. But not the whole face.