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Scratchstock usage tips sought

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Just4Fun

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Can someone please explain in simple terms the mechanics of using a scratchstock? Do you use it with a pushing motion or a pulling motion? How do you "sharpen" it? Any tips on making cutters?

The background to my question is that I have made a scratchstock - basically a marking gauge that holds a shaped iron rather than a pin - and I am having problems using it effectively. Perhaps that is not surprising given that I have never even seen a scratchstock before.

So far I have done 2 tests. My first test was on a short scrap of pine. It did work but I had 2 issues. First, it took forever. Second, the quality of finish left a lot to be desired. For both reasons I doubt I would use this tool on a real project.

My second test was on a scrap of birch, so a harder wood than the pine. This was even slower than the test on pine, but the quality of the finished surface was much better. I would be happy with that finish on a project, so I hope there is some technique I can learn to make the work go faster. Or possibly I am being too ambitious with the shape of my cutter, which is 25mm wide with 4 hollows / 5 peaks. That was just a random shape I created for testing with.
 

Derek Cohen (Perth Oz)

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I can push or pull the scratch stocks I make as the cutter is vertical. On the other hand, a Stanley/LN #66 has angled blades. These only work in one direction.

To hone a cutter, first create two flat, smooth sides to the cutter. Then make the detail square across. This gets polished. I turn a burr one each side using a small diameter carbide rod.

Softwoods, such as pine, are difficult to scrape. They take poor detail. Hardwoods are far more successful.

Regards from Perth

Derek
 

woodbloke66

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Just4Fun":7brzq6mu said:
Can someone please explain in simple terms the mechanics of using a scratchstock? Do you use it with a pushing motion or a pulling motion? How do you "sharpen" it? Any tips on making cutters?

The background to my question is that I have made a scratchstock - basically a marking gauge that holds a shaped iron rather than a pin - and I am having problems using it effectively. Perhaps that is not surprising given that I have never even seen a scratchstock before.

So far I have done 2 tests. My first test was on a short scrap of pine. It did work but I had 2 issues. First, it took forever. Second, the quality of finish left a lot to be desired. For both reasons I doubt I would use this tool on a real project.

My second test was on a scrap of birch, so a harder wood than the pine. This was even slower than the test on pine, but the quality of the finished surface was much better. I would be happy with that finish on a project, so I hope there is some technique I can learn to make the work go faster. Or possibly I am being too ambitious with the shape of my cutter, which is 25mm wide with 4 hollows / 5 peaks. That was just a random shape I created for testing with.
Use it both ways, backwards and forwards...it's a bit of 'learning curve' and feels awkward to use at first, but persevere. Pine is tricky stuff to work with and you'll get better results on a harder, closer grained timber. The cutter you've just made is a bit ambitious; I think you'd find it easier with a simple cove or quadrant shape, no bigger than say 6x6mm. Cutters are easy to shape with an engineers file.

In the hands of someone who knows how to use a scratch stock, they can produce some very impressive work.

IMG_2615.jpg


This is a linenfold panel in English Oak made by one of my old uni tutors for the Worshipful Company of Carpenters 1958 craft competition. All the mouldings were made using the scratchstocks shown (as well as the files used to sharpen the cutters) and the finish was left from the tool...no sandpaper. Don't throw these useful little tools into the long grass quite yet :D - Rob
 

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Just4Fun

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woodbloke66":3u5hcipj said:
The cutter you've just made is a bit ambitious; I think you'd find it easier with a simple cove or quadrant shape, no bigger than say 6x6mm.
I tried making a couple of smaller cutters and they were easier to use, which makes sense. Even so, it was quite slow going. OK for small jobs but I wouldn't want to do too much of it.
 

AndyT

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Although I bow to Derek's experience, I've never attempted to raise a burr on a scratch stock, and I've used one on several occasions. I've just filed at right angles then rubbed the steel on both sides, flat on an oilstone.

You'll find a big difference on different woods, the harder the better. Watch the grain carefully and work "downhill", pushing or pulling, with the cutter a few degrees short of vertical, so only the trailing edge is cutting. You should get long threads, not just dust. I'll look for some pictures later.
 

Just4Fun

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AndyT":fjs37q0n said:
Watch the grain carefully and work "downhill", pushing or pulling, with the cutter a few degrees short of vertical, so only the trailing edge is cutting.
Oh that is different. I had been using it tilted the other way so the leading edge does the cutting. I'll try your tip.
 

profchris

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AndyT":3pc5nj8q said:
Watch the grain carefully and work "downhill", pushing or pulling, with the cutter a few degrees short of vertical, so only the trailing edge is cutting.
Doesn't that depend on how you form the burr? If you stone the sides, the burr points down and so the trailing edge will cut best. If you turn a burr with a burnisher then the trailing edge won't cut at all because the burr is facing backwards - you'd want to use the leading edge then.

A genuine question, as I've never done this, but I do use a card scraper quite a bit.
 

AndyT

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Just4Fun":3pgd6akl said:
AndyT":3pgd6akl said:
Watch the grain carefully and work "downhill", pushing or pulling, with the cutter a few degrees short of vertical, so only the trailing edge is cutting.
Oh that is different. I had been using it tilted the other way so the leading edge does the cutting. I'll try your tip.

Sorry! I got that the wrong way round. :oops: Leading edge cuts. Top of blade leans into the direction of the cut.
 

AndyT

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profchris":us8hk3zl said:
AndyT":us8hk3zl said:
Watch the grain carefully and work "downhill", pushing or pulling, with the cutter a few degrees short of vertical, so only the trailing edge is cutting.
Doesn't that depend on how you form the burr? If you stone the sides, the burr points down and so the trailing edge will cut best. If you turn a burr with a burnisher then the trailing edge won't cut at all because the burr is facing backwards - you'd want to use the leading edge then.

A genuine question, as I've never done this, but I do use a card scraper quite a bit.
As above. No burr, just a "sharp" 90 degree edge, scraping on one corner.

I don't see how you could raise a burr on a tiny curved edge, at least, not if you wanted to turn it as well.
 

Derek Cohen (Perth Oz)

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AndyT":3nvuhloq said:
Although I bow to Derek's experience, I've never attempted to raise a burr on a scratch stock, and I've used one on several occasions. I've just filed at right angles then rubbed the steel on both sides, flat on an oilstone.

You'll find a big difference on different woods, the harder the better. Watch the grain carefully and work "downhill", pushing or pulling, with the cutter a few degrees short of vertical, so only the trailing edge is cutting. You should get long threads, not just dust. I'll look for some pictures later.
Andy, my apology. Replying late at night is not always a good idea.

No burr. Just flat and smoothed each side. And the edge must be perfectly square. This is what enables the scratch stock to be both pushed and pulled.

Regards from Perth

Derek
 

AndyT

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I think that makes us equal on the "senior moment" score in this thread! At least it means our advice is consistent, eventually. :D

The square profile gives two cutting edges. One cuts when pushing, the other when pulling. You tilt the cutter slightly so that only one edge touches the wood at a time.
 

Just4Fun

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No burr. Just flat and smoothed each side.
That's a relief! I have been scratching my head how to put a burr on a cutter, so thanks for the correction.
As a bonus question on the same subject, how often would you expect to re-sharpen the cutter?
 

Derek Cohen (Perth Oz)

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How often? It depends on the hardness/abrasiveness of the wood, the complexity/size and the hardness of the scratch stock.

... usually I resharpen once, perhaps twice in a project.

Regards from Perth

Derek
 

Derek Cohen (Perth Oz)

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This is a cutter made from a piece of bandsaw blade ...



Used to make a cove moulding using a Stanley #66 ...





The side of the frame curves ...







Regards from Perth

Derek
 

AndyT

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I promised some pictures.

This is my scratchstock, made for me by a much-missed old friend.



It's a good design - you can hide the side of the cutter in a groove in the fence. The underside of the stock is bevelled to help you tilt the cutter so it works. The screws are all recessed into the body, which is made from ash.

Here's a close-up of a cutter, which is one of a set I bought* in Bristol Design - I think they were by Veritas but they might have been from Ray Iles. You can see how the edge is square to the flat surfaces.



In this case it was shaping a back member of a chair, following round a curve on the end grain.



* I do also have cutters filed from bits of old hacksaw blade!
 

Derek Cohen (Perth Oz)

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Andy, one of the advantages of the design of yours is that it has a built-in depth stop.

I have made scratch stocks ala Garrett Hack, and these need careful work to avoid over cutting ...



The iron ...



The work ...



I have also re-treaded an old marking gauge ...



This works in the same manner as yours.

Regards from Perth

Derek
 

AndyT

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That's a good point, Derek. I once watched Garrett Hack demonstrate his scratchstock, and the extra stability from the long fence was very impressive. As you've shown, they are simple tools to make and there's good sense in having a selection.
 
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