Thursday, December 11, 2008

Mini Groove

Here's one way to make a 3/32" groove for a very tiny box lid and bottom.

I decided to build a box for the reference ruler, but working with 3/16" material can be a challenge, unless you're a miniaturist.

Since I learned to make scratch stock, it's become the solution on a number of occasions.

One benefit to using scratch stock is you can make profiles that do not exist in router bits. Or, if they do exist, they risk tearing out the wood on such a delicate project. With scratch stock, you can work in both directions, so you are always working with the grain; you can work slowly; you won't burn the wood, as is the case sometimes with router bits; and you can cut multiple profiles on the same blank by utilizing each corner.

For blanks, I use old band saw blades I picked up—for free—from a lumber yard that was throwing them out.

With a tiny profile like this, it was easier to use the edge of a file as a saw rather than a hacksaw to create the 3/32" wide tooth needed to rout the groove. You can use layout fluid to mark your shape, but a pen worked fine in this case.

Once the profile was filed, I honed the shape flat on all surfaces with waterstones. You need very sharp edges for scratch stock to work well.

It took about an hour to make the cutter, but routing a groove takes only minutes.

9 comments:

Bill Stankus said...

What's next - perfling a guitar or cello?

Woodbloke said...

Hi Kari - nice SS. I saw this sort at West Dean in the UK earlier in the year, used no less by the man himself. Good idea, but it only works well when for a small projection of the blade...anything larger, say 25mm and the blade starts to flap and vibrate around. My pal Pete saw the same one (there was a lot of discussion about SS's on UKWorkshop at the time)and decided to make a traditional one machined out of solid brass with an adjustable fence. He made about 6 of these things for folk various, including me and they work superbly (see my avatar on UKW) - Rob

The Village Carpenter said...

Bill, thanks for enlarging my vocabulary--I had to google that word!

Rob, I'd like to see your friend's traditional scratch stock sometime. Is it like L-N's beader?

You're right--a large projection wouldn't work with this particular profile, but as the profile gets wider, like the one I made to clean up the marks from my dovetail plane, the deeper you can go. I'm sure there are limits to what you can do and how far you can push the dimensions of the profile, but it is a nice (and cheap!) alternative to using router bits in some cases.

Woodbloke said...

Kari - I'll put a coupla pics on the Blokeblog tonight. It looks like a traditional wooden 'L' shaped SS but with the addition of a movable brass fence, so it's very shiny! But your're right, it's a very versatile and undervalued little bit of kit, 'specially for small stuff where a router bit is too big or unweildy - Rob

Larry Marshall said...

Love your scratch stock, Kari. I've got to make one of those.

As for working with 3/16" stock, I do a lot of work in 1/12 scale, where nominal 3/4" lumber is 1/16" thick. I build furniture like this, doing mortise/tenon joinery in 1/16" thick rails and styles for frame-and-panel doors (grin). Keeps material costs down.

The Village Carpenter said...

Thanks, Rob--I'll look forward to your pics.

Larry--that's impressive! What kind of tools do you use for such small work???

Gary Roberts said...

Kari Gets Her Groove Back!

Additionally, I am most impressed by how you keep your fingernails intact.

Kay said...

I like the purfling idea for a guitar. Creating scratch stock: do you tend to exchange the nibs you make into the same holders? Or have you made lots of holders and keep them all separate?

The Village Carpenter said...

Kay, the scratch stock housings are so easy to make, you might as well make several so you don't have to switch out your profiles. I imagine that scratch stock would be perfect for purfling.