Time to Lap?

[Matthew Bobek]

So, here it goes, another question on sharpening. I purchased a hock blade and chipbreaker for my Stanley #5 type 11 and I'm having some issues. My sharpening set up consists of a DMT Coarse/Extra Coarse, Norton 1000/8000, and an MK II. I began to lap the back of the new iron on the 1000 grit norton and after about 30 passes back and forth, the back of the iron had a horseshoe shaped area that was lapped, about a 1/4" up from the edge and a 1/2" in from the sides, then nothing significant would continue to happen. I jumped to the 8000 out of sheer frustration and the area polished. I'm not sure how some people can claim to take one of these out of the box and lap it "real quick" at this point.

What am I missing here? How long should it take to lap this area of a plane iron, a brand new one at that! Should I flatten the stones and start all over again? Any input would be greatly appreciated.

[David Weaver]

Unless your stone is crowned ( and I doubt it ) you need to start with your DMT until you have a uniform pattern that goes all the way to the edge.

Sometimes the hocks are a little out of flat.

If you plan on buying a lot of them, it will be worth your time to find two bolts and washers and make an iron holder with a piece of scrap lumber, and then find somthing you can lean on, even if it's just coarse norton 80 or 100 grit 3x paper.

if you have a flat surface to put sandpaper on, some adhesive and a borg nearby, I would get 80 or 100 grit 3x and a dust brush. It will take at most 1 sheet of paper to rectify the situation.

It may take an hour on the 1000 stone, and many flattenings.

3x paper will leave all but a brand new DMT in the dust. The only thing that I've found that outruns it is loose diamonds on a piece of mild steel, but that's a $50 proposition with the diamonds and a reasonably thick and flat milled piece of steel.

Either way, an iron holder is essential so you can get a lot of pressure on the iron, and not just the amount your fingers will tolerate.

I've never seen a hock iron that I couldn't flatten and have to a polish in 15 minutes, though I have had a couple that took me 45 early on because I didn't have the right tools.

[Sam Takeuchi]

So you have a hollow in the middle, but the sides and along the edge are flat and polished? Then you are done. That's good. The dip in the middle should catch up to be flat over repeated sharpening and back polishing. In fact, I personally think that's how all blade should be for efficient flattening.

If you insist on flattening the entire back at this point for whatever reason, do it on a coarser grit to remove the bulk of metal. And then move onto #1000 to clean the rough surface and then polish away on a #8000. However, I think jumping from 1000 to 8000 for the back is a significant jump and probably cause excessive wear on the stone as well as takes a long time to remove scratches from #1000 stone. I'd add in between grit.

[David Weaver]

I'm assuming the opposite as sam, that the area that is lapped is the area away from the edge. If I have it reverse of reality, the OP is done.

[Sam Takeuchi]

Oh you may be right.

[Jim Koepke]

I would get 80 or 100 grit 3x and a dust brush.

Another way to remove iron filings from the abrasive sheet is to wrap some paper around a magnet. Wave the magnet over the abrasive to pick up the filings. Then when the paper gets loaded with iron filings, just toss it and the filings in the trash and use a new piece of paper.

My sharpening/lapping bench has a screw in the side just to hold the magnet.

This method may not be good if you are using diamond lapping plates with ferrous content.

jtk

[Tri Hoang]

With a new iron, I normally start lapping at 1000. After a few passes, I'd inspect it for wear uniformity. If it looks uneven, I'd drop it down to a 220. I think the key to efficient lapping is surface flatness, especially on the coarser stones.

The main objective is to lap it flat on the coarsest stone. Once I get it flat on the 220, the remaining task is to erase scratch marks from the previous stones. Thus if the coarser/finer stones don't agree, one would have to work a lot harder on the finer stones instead of just erasing the previous scratch marks. Using a lot of pressure on the coarser stones might speed up the process. However, if the excess/uneven pressure causes the blade to wear out of flat, one would end up spending extra time on the finer stones...so there is a balance there.

The key is flatness because of its repeatability...and the coarser the stones are, the more important it is to keep it flat. Take the time to dress them flat.

[john brenton]

If you still have problems I think a pic would be helpful. I understand your post to mean that you are not getting flat all the way to the edge because of a belly...not that there is kind of a hollow grind like you find on the Japanese irons and chisels that you're worried about for the future.

1/4" sounds pretty bad though. I wouldn't waste the life of my DMT on that. If it was a cheap iron I'd say just hone that 1/4" and worry about the rest when you come to it...which may remedy itself along the way through regular sharpening, but as this is a new piece I'd send it back, or at least ask for a credit towards another item.

On the topic of sharpening though, one thing I've found helpful is to think of sharpening as the same as planing. You don't just plane back and forth indiscriminately and expect to get a flat board. You've got to inspect and work it, taking down the high spots etc. Again, I wouldn't do that with a new iron, but on old ones I may gradually slope that low part towards the high part instead of removing all that metal. When I'm having a hard time I take a break to polish the surface (1000 or 4000 is enough) just to really see what's doing. Have you tried marking the back to check progress?



So, here it goes, another question on sharpening. I purchased a hock blade and chipbreaker for my Stanley #5 type 11 and I'm having some issues. My sharpening set up consists of a DMT Coarse/Extra Coarse, Norton 1000/8000, and an MK II. I began to lap the back of the new iron on the 1000 grit norton and after about 30 passes back and forth, the back of the iron had a horseshoe shaped area that was lapped, about a 1/4" up from the edge and a 1/2" in from the sides, then nothing significant would continue to happen. I jumped to the 8000 out of sheer frustration and the area polished. I'm not sure how some people can claim to take one of these out of the box and lap it "real quick" at this point.

What am I missing here? How long should it take to lap this area of a plane iron, a brand new one at that! Should I flatten the stones and start all over again? Any input would be greatly appreciated.

[Matthew Bobek]

Thanks for all the replies guys, it actually appears to be a hollow grind. The center still has the machinig marks and the horseshoe shape I described runs along the edges. So, I think it will be ok, and hopefully it will wear down with time as I sharpen it. As for the life of my dmt I spent the afternoon flattening out the backs of these darned Irwin Marples chisels i have, so hopefully not too much damage was done, I can't wait to buy some premium chisels. The reason I bought the waterstones was to get away from sandpaper, so perhaps I'll try the 220 stone in the future.

On another note has anyone noticed the Hock chipbreaker/blade combo being a little tight in the mouth even with the frog backed off. I'll mess with it more tomorrow since I've had enough for one day. Thanks.

[john brenton]

That should be a relief for you. Flat's better IMO, but a hollow sure as hell beats a belly. I'd still go for the discount on a future item...but I'm sleazy like that.


Thanks for all the replies guys, it actually appears to be a hollow grind. The center still has the machinig marks and the horseshoe shape I described runs along the edges. So, I think it will be ok, and hopefully it will wear down with time as I sharpen it. As for the life of my dmt I spent the afternoon flattening out the backs of these darned Irwin Marples chisels i have, so hopefully not too much damage was done, I can't wait to buy some premium chisels. The reason I bought the waterstones was to get away from sandpaper, so perhaps I'll try the 220 stone in the future.

On another note has anyone noticed the Hock chipbreaker/blade combo being a little tight in the mouth even with the frog backed off. I'll mess with it more tomorrow since I've had enough for one day. Thanks.

[David Weaver]

Another way to remove iron filings from the abrasive sheet is to wrap some paper around a magnet.


That's smart!

[David Weaver]

I'll try the 220 stone in the future.



nooooooooooooooooooooo....junk!

stick with diamonds or sandpaper in that grit range.

Schtoo has one that he says works well, but I'm assuming you're referring to the norton. I had one, I had to give it away because I felt guilty about selling it. It is completely unsuitable for flattening anything.

Maybe the most coarse stone you could use would be a bester 500.

[john brenton]

Yup. My Norton 220 stone is not even a year old and it's already about 1/4" thick from flattening...and I've been careful with it! I never found it to be valuable. I've even retired the 1000, but it was much more effective than the 220. I go straight from the coarse grit DMT to the 4000, then to the 8000. I really don't know why people think the 4000 is unnecessary...it does a great job for me.

For the OP...if you ever have a whole lot of material to remove I would definitely invest in some kind of flat surface and use sanding belts. They remove material fast and you can preserve your stones for honing, not shaping.


nooooooooooooooooooooo....junk!

stick with diamonds or sandpaper in that grit range.

Schtoo has one that he says works well, but I'm assuming you're referring to the norton. I had one, I had to give it away because I felt guilty about selling it. It is completely unsuitable for flattening anything.

Maybe the most coarse stone you could use would be a bester 500.

[James Taglienti]

I just bought a Hock cutter for my 603. It's a french-made cutter and it was a little tough to flatten. It had fine lengthwise machine marks on it. The face was convex a few thousandths. The back, however, had a nice hollow on it. :confused:

It took about 20 minutes on a coarse diamond stone and it was ready to move on. Not a big deal, but I had expected more from Hock.

The 10 1/2 cutter I bought was an older Hock, US made, and it was even worse. This one was struck, not laser engraved, with no origin of manufacture printed on it. It had circular grind marks across it. It took about 40 minutes to get right.

[bradley strong]

I just upgraded a vintage #6 using the Pinnacle blade and chip breaker, and I couldn't be happier. Hock irons are notorious for not being flat.

The good news is that you don't need to flatten the back of a plane iron like you do a chisel. Use the ruler method to flatten the back. It works great and cuts down the sharpening time to almost nothing.

[Aaron Rappaport]

David, I see you're recommend Norton 3x above. Do you use the sheets or the blue zirconium belts?

If you do use the belts, how does one get the curved part to lie down flat? Also, how much pressure (subjectively, of course) do you use? I've tried using the belts for various flattening and sharpening tasks and have been unpleasantly surprised at how quickly they dull. Maybe I'm using to much pressure.

[Jim Koepke]

Thanks for all the replies guys, it actually appears to be a hollow grind. The center still has the machinig marks and the horseshoe shape I described runs along the edges. So, I think it will be ok, and hopefully it will wear down with time as I sharpen it. As for the life of my dmt I spent the afternoon flattening out the backs of these darned Irwin Marples chisels i have, so hopefully not too much damage was done, I can't wait to buy some premium chisels. The reason I bought the waterstones was to get away from sandpaper, so perhaps I'll try the 220 stone in the future.

On another note has anyone noticed the Hock chipbreaker/blade combo being a little tight in the mouth even with the frog backed off. I'll mess with it more tomorrow since I've had enough for one day. Thanks.

It is very common for the mouth to be tight with a Hock blade. If there is room for the frog to move back a bit, my suggestion is to remove metal from the back of the mouth.

I have found water stones under 1000 grit to be unusable due to how quickly they wear down. In those areas, it is likely more economical to use abrasive sheets or diamond stones.

One thing to be careful about when flattening the back of a blade is that you are keeping it flat. It is very easy to rock it and just hit the edges. A push pull along the long axis can help to avoid this.

jtk