In my last post I showed you how I apply a solid wood edge treatment to plywood panels. This is something I don’t do very much of and in a perfect world I’d be using solid materials in every project but sometimes design can dictate the materials needed and in this case the plywood is a necessity.
I think the success you’ll have with the techniques described are those final few passes with a card scraper bringing everything together flush. Its these last few passes that can either tear away those precious veneers, uncovering a cross grain layer underneath and making for a less than perfect panel or the opposite- bringing the two surfaces true and making the transition from solid wood to plywood veneer almost seamless.
Sounds pretty straight forward but the success you’ll have with this technique is directly effected by the tool you’re using and just how sharp the edge of it is. I thought it would make sense to show you how I prepare a card scraper for these final finishing steps.
To begin I’ll choose a card scraper for the required task- some are quite thick and extremely hard to flex with your fingers alone while others are thin, capable of almost bending around a bevel or some other concave shape or edge treatment. The idea here is to bring two surfaces flush and flat so I don’t want to use the super flexible card scraper nor do I want the ultra thick version to tear into any of the veneer. I go with a medium thickness card scraper that will stay true across the surfaces but ‘give’ justa little so I can manipulate the attack across the wood grain. I always store a card scraper or two in my tool tray and use them almost daily for removing glue or just a quick surfacing of the bench top or piece of lumber. Once I select the card scraper for this particular job I’ll spend a good 15 minutes to prepare it. I won’t have to do all of these steps again for the duration of the project but will need to re-hone and dress the edges as well as re-applying the burr a few times through out the project.
I begin with the aid of a jig- in this case it’s a jointing/edging jig that holds a file square to the fence establishing a perfect 90 degree angle for removing the worn metal from the edge. I’ll firmly clamp the scraper on edge in my face vise and proceed to take just enough passes to clean all of the old edge away establishing a clean, fresh surface on both long edges of the card scraper. A bit of pressure and usually 4 to 6 passes is all that’s needed to cut away the soft metal. This freshly jointed edge is now still extremely jagged and very sharp so be careful while handling the tool from this point on.
When the jointing is complete I’ll move over to the sharpening bench and get ready for some water stone work. As an aside here I should mention the sharpening bench is working as planned but I still take the time to throw down an old tea towel to help absorb the water and slurry while using the stones- what can I say, it’s still fairly new and I want to keep it looking good! As mentioned the card scraper now has an extremely sharp edge so I begin on my 220 grit stone with the scraper flat on its side and work away the burr along the edge. This only takes a few passes and I’ll switch over to my 1000 grit stone. I could have began on this stone but I sometimes worry about gouging it with the sharp edges on the scraper. The coarse 220 is a real workhorse and the fresh burr is quickly removed.
Now on the 1000 grit stone I hone the flat side surfaces until I reach an even level of gray scratch marks. The process involves four separate steps hitting the four long edges of the scraper. With the sides dressed I’ll move onto the edges and holding the scraper firmly against a jointed off cut of oak, I can keep the edge square to the stone surface and begin bringing up the finish on this thin strip of metal. Be very careful whenever you dress the cutting edge of a card scraper with a water stone; these stones are relatively soft and an edge could easily dig into the surface damaging the stone.
Both long edges are finished at the 1000 grit stage and I’m ready to move onto my 8000 grit polishing stone. I continue with the edge polishing, using the oak guide block to keep the card scraper at a constant 90 degree angle to the surface. I’m using very little pressure here and after a dozen passes I’m turning it over to dress the opposite edge. Checking as I go with my magnifying bench light, I’m looking to see if I’ve successfully removed all of the previous scratches left from the 1000 grit stone. I find the edges are shining and polished so I can now finish off the stone work with polishing the two side surfaces. This is the same process you would do when you hone the back of a plane iron. Here I use David Charlesworths ‘ruler trick’ so I won’t have to polish the entire surface but only the thin leading edge. I polish both sides and edges on the 8000 and then give the scraper a good rub of Jojoba oil. From there its back to the face vise in my work bench to roll a burr. As a side note again on the sharpening bench, I think a small metal vise attached somewhere may be something I’ll look at in the future. I have a small metal vise back home in my shop in Cape Breton and may bring it back with me next summer. That’s one of the only things missing from my sharpening bench design.
Begin by burnishing the faces of the scraper- lay the tool flat on your bench and burnish the long sides to draw out the steel before turning the burr.
Turning the burr is sometimes the most difficult part of dressing a card scraper; all of the work so far may be for not if you screw this last step up! So go easy, start straight across horizontal and slowly work the edge of the steel. Turning the burr can be done with a dedicated burnisher like the one in the next photo. This is an oldie I’ve had for many years and it could really use some TLC- (its on my list)
A burnisher should be well polished and free of any grim or nicks, scratches or rust. Spending time on the finish of your burnisher will help to prevent spreading those undesirable blemishes from the burnisher back over to the freshly polished card scraper. Starting at horizontal and working down the length of the scraper, carefully push the steel out and away from you. You don’t need a whole lot of pressure and after a few passes you should be able to feel a small burr (wire edge) appearing. This small burr or hook is what does all of the cutting. You then want to start changing the angle of the burnisher slowly pushing that small hook over so it begins to roll up to finish at an angle in the 15 to 20 degree ball park. The more hook, the more aggressive the cut. Some people will only draw the burnisher across the scraper at the first position and never go on to the angled approach thus never having a very agressive cut. They prefer this cutting action but I find a small hook speeds up the cut and changes the attack while in use. If I roll a small burr at a more relaxed angle I end up having to tilt the scraper away from me further while in use. I prefer being able to hold it in more of an upright position so the greater hook means less angle while cutting. Hope that makes sense- sometimes it’s hard to write about certain hand tool techniques and showing these techniques in person is so much easier. (hey, why not sign up for a private class?)
If you don’t like using a burnisher or you don’t yet feel confident enough to free hand the hook, then the jig shown in the next shot may interest you. It’s from Veritas tools and takes all of the guess work out of turning a consistent burr on the edges of card scrapers. This small jig is able to be pre-set with the desired angle from 0 to 15 degrees and a few light passes are all that’s needed to roll over the tiny wire edge. I use it quite often and have never had any problems with it.
Roll the burr on the four long edges- you may try to experiment here a bit by turning a heavy burr on two sides with a lighter cut on the opposite edges. Now you can flip the tool around while in use to get a sense of the amount of hook that feels comfortable to you and your work. Once the burr is established its time to put this thing to work- ironically enough the card scraper shouldn’t scrape the wood at all but cut it. Fine shavings are what to watch for in this last shot you can see a small sample of shavings. As I mentioned this entire process took a whole lot less than it did to write about- maybe 5 to 10 minutes in total?
Now that its been cleaned up I won’t have to do all of these steps for awhile.
Try it out for yourself and you’ll soon develop your own routine and techniques.