How to cut a stopped groove for inlay - scratch stock?

[Woodmonkey]

On the lid of a box I would like to cut a groove between the veneered panel and the solid lipping to inlay a strip of ebony. Too scared to do it with a router!
Have read about scratch stocks could this be the way forward? How do I go about making one for this purpose?

 

[Peter Sefton]

I would do it with a plunge router, but it's easy to make a simple scratch stock.

Take a piece of Beech or similar hardwood and cut it about 150mm long 50mm wide and 20mm thick. Cut a corner out of it taking away about away about 1/4 of the timber (75mmx25mm) Take saw cut 2/3 of the way along splitting the 20mm thickness in half this leaves a slot for the scratch stock cutter. Screw a couple of screws through the saw kerf to tight it down onto the cutter.

Make a cutter from an old hack saw blade to suit.

We sell the scratch stock blade blanks, if you wanted to buy one I would drop a drawing of the scratch stocks we make in the post.

Good luck Peter

 

[custard]

I've done it both ways many times and I'm not sure the risks are greater with one method rather than the other! A router can kick a little when starting, or wobble on the plunge, either of which will compromise the cut. But equally you can slip with a scratch stock, and it's also much more prone to tearing out the cross grain veneer.

Personally I prefer the router, especially for the specific application you mention as whatever cutter you use it will be engaging into two dissimilar materials, veneer on one side and lipping on the other, in my experience this really does make a scratch stock difficult to control and (at a micro level) it'll be bucking and skewing in your hands even after you get the cut started. See my later link to the Garrett Hack style scratch stocks which go a long way to overcoming this problem.

Having said that it also depends on how big the box is, as I'd favour the scratch stock for smaller workpieces where the router may be less well supported. If you do use a router it's important to make sure there's good support throughout the cut, which may mean building a run-on/run-off frame exactly the same height as your box, to which you can attach stop blocks to position the router precisely.

And to really muddy the water, the choice isn't just between scratch stocks and routers, there's also other hand tools like this,

https://www.lie-nielsen.com/product/too ... ?node=4180

or like this,

http://www.leevalley.com/US/Wood/page.a ... 43314&ap=1

or even like this!

http://www.leevalley.com/US/wood/page.a ... at=51&ap=1

I've used the Holtey purfling cutter and the Lie Nielsen inlay cutter and they both have the advantage of scribing the edge and are therefore that bit cleaner across the grain. But by carefully going over the workpiece with a cutting gauge you can also scribe lines, and use the scratch stock to remove the waste between the gauged lines.

Finally, most British scratch stocks have a pretty short fence. They still have their uses but I'd encourage you to look at this alternative, Garret Hack style of scratch stock.

http://www.finewoodworking.com/how-to/v ... stock.aspx

I've been using one of these for about a year now and for straight line cuts it has two huge advantages, most obviously is the longer fence, but also the way you can rock it fore and aft to present the scratch stock's blade to the best advantage, that can make a big difference.

Good luck!

 

[Cheshirechappie]

In his book 'The Resourceful Woodworker' Bob Wearing gives a design for a double-knife cutting gauge. Very simple idea - just a bog-standard cutting gauge with the knife slot extended so that two single-bevel knives, bevels inwards and a suitable packing between them, are wedged in the stem instead of a single knife. That can define the inlay groove, and a simple scratch-stock can take out the waste, any cleaning up being done with a very small chisel. The same double-knife gauge can be used to cut the infill string, too - reverse the knives so they're both bevel outwards, and change the packing to the same width as the groove. The packings in each case are just little slips of wood cut to the desired size.

There's no doubt that the 'proper' tools that custard linked to above will work quicker and are almost certainly nicer to use, but there are low-cost ways too.

 

[mouppe]

Veritas make a fantastic supplementary kit for their router plane which allows you to precisely score the outside lines for any size of inlay from 1/16" to almost 1/2". Then you can follow up with a chisel, router plane blade or electric router to remove the waste in the middle. I made a video about it on youtube which you can find if you search for "Veritas inlay." For delicate work like a box I prefer to use hand tools.

http://www.leevalley.com/en/wood/page.a ... at=1,41182

I also have the Veritas beading plane but it's terrible frankly.

 

[Woodmonkey]

Thanks fellas some useful info there, although I have more or less come to terms with doing it with a router. Did a couple of test cuts today on some scrap with no mishaps, just getting twitchy as I really don't want to ruin my lovely bit of walnut burr! I read somewhere that slowing the router down is a good idea for small delicate cuts like this, does anyone concur? I thought it was a case of the smaller the bit, the faster the speed?

 

[custard]

Thanks fellas some useful info there, although I have more or less come to terms with doing it with a router. Did a couple of test cuts today on some scrap with no mishaps, just getting twitchy as I really don't want to ruin my lovely bit of walnut burr! I read somewhere that slowing the router down is a good idea for small delicate cuts like this, does anyone concur? I thought it was a case of the smaller the bit, the faster the speed?

I've done this quite a few times, always at full router speed. Maybe that advice goes back to the days when many routers didn't have soft start, so would kick at higher speeds?

 

[mouppe]

Score the edges with a knife to prevent tearout. I wouldn't slow the router down.

 

[custard]

Incidentally, what bit are you using? I've had good results with the 1.0mm and 1.5mm Wealdon cutters.

http://www.wealdentool.com/acatalog/Onl ... k_237.html

If your router arms are long enough having a fence on each side makes this a much more secure process.

Good luck!

 

[Woodmonkey]

I've got a 3mm trend cutter since I'm making my own banding and I've successfully cut some 3mm thick ebony on my band saw, 2mm or less might be asking a bit much without me buying a much finer blade

 

[custard]

I've got a 3mm trend cutter since I'm making my own banding and I've successfully cut some 3mm thick ebony on my band saw, 2mm or less might be asking a bit much without me buying a much finer blade

I'm not so sure, you can get 1mm stuff from pretty much any bandsaw, the trick is you cut your inlay material at about 1.5mm, then plane it down using a block plane with the heel resting on the bench giving a very slight wedge profile to the inlay which helps getting a snug fit.

The benefits of narrower inlays are twofold, first they look (to my eyes at least) that bit more elegant. Secondly if something does happen to go wrong with your 1mm or 1.5mm inlay, you can re-rout over the top with a 3mm cutter, so by starting fine you have a Get Out Of Jail Card still to play!

 

[Woodmonkey]

Hmmm good logic, although that would mean spending another 15 or so quid on a smaller cutter!

 

[Mr T]

Use full speed when cutting. On wider inlay downward spiral cutters give a nice clean line, but that is not an option at this width. I find a sharp cabinet scraper if good for thinning down stringing.

Chris

 

[Trafalgar]

If you do a lot of this type of work a soft-start router might be a worthwhile investment.

 

[Woodmonkey]

Routed it out today, don't know what all the fuss was about!

And with the inlay after cleaning up a bit

 

[AndyT]

Wow!

That's a spectacular bit of burr and the stringing frames it nicely. Can we see the whole thing please?

 

[Woodmonkey]

Thanks Andy, I'll post some pics of the box when it's finished.

 

[Carl P]

I'd just ike to echo Andy T, so Wow (etc),

Cheerio,

Carl

 

[custard]

Well done that man!

=D>

 

[bugbear]

Super design - the black stringing picks up the dark tones of the burr beautifully.

BugBear