Scribing tips?

[Andrew Wayland]

I'm going to be adding a 9ft long shelf on a wall. Of course, the wall waves and contours quite a bit over the length.

I'm putting a plywood base under the hardwood for support, and I used a compass to scribe the wall profile to the wood. I put the saw at a slight angle to help with the gaps, but using a jigsaw I had less than favorable results.

Before I hack up a beautiful piece of cherry: does anybody have any suggestions as to how you scribe your workpieces? I'm guessing half the problem is my jigsaw control, but maybe there's something I'm missing?

[glenn bradley]

There are more jigsaws that pretend to be tool than almost any other hand held power tool. I can still recall my eureka moment when I first used a Bosch 159X series jigsaw. I was astonished. I thought jigsaws were jumping-jacks with a blades attached used to hog out rough openings for HVAC ducting or large domestic animals. With a powerful, variable speed, jig saw with a high-end cutter you can leave near glass smooth, very controllable cuts.

If your jigsaw is well powered and cuts with a minimum of vibration it may just be that you have trouble following a line. This is not unusual with hand held or power curve cutting tools. One method that works well for some folks is to draw a pair of lines about 1/16" apart and run the saw between them. Another method is to cut "pretty close" to the line and clean up to it with a rasp or a sanding block.

I prefer a barrel grip so the Bosch 1591 with a T101B blade is my weapon of choice for 4/4 through 6/4 hardwoods when cutting curves.

[andy bessette]

Once you have the work piece roughly scribed, you can refine that by simply laying a pencil on its side and re-scribing. Then sand to the line.

[Kevin Jenness]

Here's how I do it. Put blue masking tape on the work piece, mark the scribe and cut away the tape on the waste side with a knife. I use a knife against a scrap or a blade taped to a scrap to mark and cut at once, but you can mark with a pencil compass and then cut to the marked line freehand. This gives you a well defined line to cut to and suppresses tearout beyond the line when sawing.

I use a power plane to get very close to the line and clean up with a block plane , rasp or 80# hard sanding block as necessary. Most people use a jig saw for roughing, some use a belt sander or even a disc grinder (fast but messy). In any case, undercut the rough strokes and sneak up on the line by hand.

[Andrew Wayland]

Ahhh: I like the rough-cut then fine tune with belt sander idea! I feel that will work very nicely.

New tools arent really in my budget (I blew that on lumber!). I'm pretty heavily invested in Ryobi battery tools right now (again...budget being the reason, and they've served me well as a casual DIYer).

[Stan Calow]

Andrew, I've not done this, but how about making a pattern on mdf or something similar, and routing the edge with a pattern bit? I am much more confident in my router than jigsaw.

[Chris Kiely]

Pencil for scribing, power planer for rough stuff and clean up with a belt sander. Magic eraser in case you get pencil marks on the walls.

[Darcy Warner]

Accuscribe pro, festool ras to the line.

[Leo Graywacz]

If the wood is dark apply tan or green masking tape. Put against the wall, if there is a large bump balance things out on either end. Use the scribe to mark the tape that has been put on the edge of the wood. Depending on how much you have to take off tells you if you need to use a jigsaw or not. Remove the bulk of the wood with the jigsaw if required. To finish up use a belt sander perpendicular to the board, so the belt is cutting from the pencil line down. This keeps the top clean and chip free. I've become very partial to the PC 2 1/2x14 small belt sander with a 60 grit belt.

[Charles P. Wright]

If you have a bandsaw, you may be able to use that instead of the jig saw. I use either the jig saw or bandsaw tilted followed by a sander. A belt sander with a low grit paper will remove material quickly enough, but it is messy.

[Leo Graywacz]

Put a vacuum on it and it's nearly dustless.

[Patrick Walsh]

Find you largest dimension both depth and width. Figure out about generally how far things are out. 1/8" 1/4" 1/2 you get the idea.

If the this shelf goes wall to wall get it fitting left to right first. If i want a stain grade fit. I usally take two pieces the same depth as the shelf and cut like two 12x the depth pieces. I then take a framing square, speed square or whatever square and get a idea of what is going on.

Based on what my square tells me i reference one side of my 12" by whatever scrap tight to the wall and scribe. I get the exact angle of the left and right side of my shelf cut into these scraps. As i cut them i mark the angle on my saw use to cut. If they neeed further scribing i just use a pencil referenced off the wall. Just remember not to spin your pencil as you go and keep it on the same side you started the scribe with.

I then mark the depth of my shelf on the on the wall. Use blue tape if you want. I the take a front side to side measurement and back side to side measurement. Based on my desired finished depth i add whatever my discrpency is on the back wall to my rough stock in the event i screw up. When im all done i use a teack saw if need be to bring my shelf to depth. I then finish the edge how ever previously planed. Bullnose, edgeband, nosing...

Now pick one side left or right to measure from and stick to it. Correlate this with what one of the two blocks that you previously scribed. You are now going to start by transferring this scribe to your actual work piece. Place your scribed 12x whatever block that you previously scriped on your actaul finished stock. Reference the two front edges together. Use a speed square or level to assure they are perpendicular to each other. Transfer your scribe to the board and cut it out.

Once this is done go back to your left to right measurments indexing your now front and back edge of you now scribed side. Measure and mark both your front and back side to side width based on your notes. Double tripple quadruple check if you need to. Mark your finished stock. Now take your other 12" x whatever scrap and and align the two front edges. Dont forget to use a straight edge again to assure the front edges are aligned. Transfer the corresponding scripe and cut.

Now the board fits left to right. With it in place push it as tight as you can to the back wall. Make sure it is even left to right. It should be based on your left and right scribes. If not figure out what went wrong and correct that before moving forward. Once it is even left to right i find the largest gap and measure. If it is 1/4 i cut a 1/4 scrap. Place this scrap between the wall and your pencil. Drag the two along the wall together transfering the wave of the back wall onto your board.

If you left your board a little extra deep to begin you should be able to determin by how much your workpiece is to deep. Whatever extra depth you have again make a scribe block. Re scribe the back and cut. At this point the sides may have changed slightly. If so you can now just use the tip of your pencil to re scribe the sides.

I usually just set my TS to 1-3 % bevel and free hand rip about 1/8-1/16 from the line. I then block plane and sand to a perfect fit. If you are not cozy ona TS use a jig saw set at a bevel to creat a undercut.

Scribing is fun once it isnt a nightmare!