Saturday, February 11, 2017

Scratch stock

Traditionally small moldings profile were simply scratched on the edge of the pieces, while bigger profiles are executed using a plane.

From L-R
1/4 in beading plane and 1 inch (8/8) beading plane
Flat part on the right is the depth stop

Same profile, a bead, on a scratch stock

They are called scratching tool due to the vertical position of the blade, and scrape rather than plane the profile.

There are many ways to make and use a scratch stock, and they are used somewhat like how you would uses a marking gauge. Sometimes you come across old marking gauges which had been modified to hold a scratch cutter by cutting a slot at the end of the beam closed by a screw or two. They have a stock, or beam, to hold a small steel cutter vertically and a fence to control the location of the profile. They would be almost impossible to use without a fence and make a straight profile, unless there is already a profile started or by using a batten on the piece of wood as a guide.

A straight fence allow you to guide the tool on a reference edge and a curved fence around a curved profile, either concave or convex. Hence they sometimes comes with a removable fence: a straight one and a curved one. E.G. Stanley No 66. Of course having loose parts often meant that the fence(s) often get lost thru the years...

In use they are tilted forward in the direction of the cut, making the cutter trailing. The final profile being scratched vertically. They can be used either by pushing away from you or pulling toward you. In order to do that, the beam must be tapered or rounded.

The last few pass vertically is important if you want to reproduce exactly the cutter profile. For example when rehabbing a moulding plane sole profile.
When you tilt a circular profile you are cutting more of an ellipse than a circle.

Sharpening is mostly done by rubbing the flat faces on a polishing stone, eventually you will have to touch up the shaped profile, or to create your original profile, for which a chain saw file would be small enough to do the job, you can uses shaped slipstones, diamond files etc. The profile is filed straight across, so when one side of the cutter is getting worn, simply reverse the cutter to get a fresh edge. A sharp cutter has a sharp arris between the flat face and the edge.
A good source of spring steel to make cutters would be from an old saw blade, either a bandsaw or a handsaw, old card scrapers and etc.

Being very simple to make using shop scraps, they were often craftsman's made.
Here is another similar version. The idea is to cut a narrow kerf to slide the blade in and out exposing the right amount of the profile desired. The blade is secured by closing the kerf with a screw pressure.

The Hock tool version
Pic from Amazon

Paul Sellers poor man versions: a Beader using similar methods as above or using a screw as the cutter 

As you can see there are very easy to make,  but you know there has to be a way to invent a better mousetrap....
And so there were ...

Probably one of the first patented and manufactured scratch stock were the Windsor beader or scratch stock.


First patented Windsor beader 

Patented by Lawrence Poole in 1885,  and made in Windsor, Vermont (why we call them Windsor beader or scratch stock), the first version sport an all wood body and fence in one piece.

The first wooden version as my example above

The later metallic version perhaps better known. There has been modern reproduction of this tool in later years and cutters are sometimes available new for it. Pics from DATAMP 

The rotary cutter disc, present 6 different profiles around its circumference. The various profiles are selected by slackening the nut that press the cone against the cutter, turning it until the desired profile is sticking out by the fence, then retighten the nut. The fence is fixed hence it is only designed to work on the edge of the boards. Later models have a movable metallic fence.
See Lee Valley newsletter Vol 6 No 6

Stanley came out with its No 66 scratch stock 1886-1941, it is often found missing its cutters (6) and the fences (2). Fortunately Lie-Nielsen has been making a reproduction and the parts are interchangeable

The Lie-Nielsen version of Stanley No 66.
The bent blade, rarely seen in the wild, is a two ended router blade.
Pic from Lie-Nielsen site

Stanley also had the smaller No 69, which is fence less and designed to be pushed only, since the blade is leaning forward. Being fence less it can be used anywhere on the board, providing you use a batten board as a fence.

Stanley No 69, was never much popular owning to its difficult useage, 
hence rare and valuable.
Pic from Patrick Blood & Gore

Preston had a metallic one as well, No 1393S (1909) which is now being reproduced by Lee-Valley.
There was a short lived version in bronze made by Woodcraft earlier. (Early 2000s) which came with two (2) fences.

The original Preston No 1393S, from 1909 catalog

Lee-Valley also came out with their own designs, first in wood then in metal with wood handle and finally their Preston reproduction
All three versions used the same blades, bonus!

The original wooden version along with their latest reproduction

The blade can be bury in the fence to reveal the profile desired

The beam at full extension, the blade can also be secured in another position, hence the three (3) screws. The beam is round hence can be tilted in use.


Similarly on this one, the sole and the fence have a small curvature to them, enabling the tool to be tilted in use and to go around curve edges


LV third version also uses the same blades set (8) as the two others
Pic from LV site


 A close cousins to the scratch stock are another class of tools called Coach routers or Quirk routers used in the coachmaker trade. They were used to scratch the small profile around curved members on the coach. Often cutting a narrow groove, (routing) to insert an inlay contrasting piece of wood.

Preston Quirk router.
Cuts a narrow groove
Pic from EBay

Preston Sash routers
From T-B Bead, Ovolo and Lamb tongue
Pic from HTPAA.ORG.AU

Notice the two cutters? There are mirror image of each other and allow you to attack the grain from both directions. There are also unique by having a short sole surface, like a plane. Preston seems to had been the only maker of these unique tools. Pic from EBay

These small profiles exist for a very good reason, it prevent wear on the edges of the pieces, because there are no sharp arises left, but rather a small rounded over.

Notice the wear on the top edge of my dado cutters storage box I made back in the 90s. I was supposed to make a cover or lid but never got around to it :-) 
A small bead detail would have prevented that, hence why often used on top front of drawers or on shelves front edges

Some scratch stocks can cut small flutes or reeds in the middle of small parts ( think table or chair legs) if they have a movable fence.

Scratched profile on front of dining chair's legs.
Accent carving on stretchers by Rudy :-)

Another similar types of tools are used to scratch or rout out small narrows channels for inlays .

Do they still have a place in our modern shops? Well, you try to balance a high speed rotary tool (electric routers) on a small narrow piece and let me know how you make out...

One last thing, owning to their rotary profiles and rotation speeds, a router bit cannot cut some of the more delicate profiles made by a simple scratch stock or beader tool.

Scratching the profiles is also quieter and often faster than using them 'Lectric screaming beast :-)

Bob, scratching Rudy ears :-)

8 comments:

  1. Hi Bob. A really great post on scratch stocks. I made my first one last year - a simple "L" shaped thing. But your post has given me some better ideas. I've a question for you - you mentioned another similar type of tool used to rout out narrow channels for inlay. What is that tool called?

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  2. Hi Bob, great post. Very thorough. I didn't know so many types were manufactured!

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  3. Hi Bob.
    Thanks for a great post on scratch stocks.
    How very nice of Rudy to help in carving the stretchers :-)

    Brgds
    Jonas

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  4. Bob,

    Good info...but damn you are hooking my tool collector. I looked at eBay for the first time in months. That's the bad news, the good is I didn't bid on anything.

    Treats for Rudy just because,

    ken

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  5. Thanks Matt, name of the inlay tool? Would have to get back to you, dont remember off hand, but i did realized this AM reading your cabriolet post, that i forgot another class of tools: Chairmakers chair devils.

    Bob, playing with Rudy

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  6. Hi Brian, thank you. Indeed there are afew and i still managed to forgot some more :-)

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  7. He he Jonas, yes Rudy is quite the helper :-) he has also taking on chewing the corners of the baseboards moulding.... make me wondered why i bothered fuzzing with the miters so much...it does not matter much anymore :-)

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  8. Ken you are feeling weaker, you must get that other marking gauge, and hoh dont forget you need another saw :-)

    You're welcome, the least I can do for you to help endure winter were you are :-)

    Bob, who just listened to another snow warnings...

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