Can't see knife lines

[Susumu Mori]

Hi all,

I understand that using knives for marking have certain advantages. However, I often have difficult times to see them. This is particularly troublesome when I want to use them as a guide for sawing.

I am wondering if you have similar problems and have some useful tips.

Your experiences and advises would be highly appreciated.

Susumu

[Mike Ontko]

I know it seems redundant, but if I'm working with a light-colored wood, like maple, I'll darken my scribe lines with a pencil.

[Andrew Pitonyak]

Depends on what I am cutting. For me, a knife line usually means that I am cutting dovetails (not always, but usually).

For me, the biggest help is a strong raking light. For example, I have this lamp (in the non-clip-on version)

http://www.amazon.com/Energy-Efficient-Clamp-Lamp-Light-Black/dp/B014S73JYO

I move the light as I cut so that it illuminates the line with a raking light to great effect.

The second item is that I need a good deep cut. I have done some cuts that were very lite and difficult to see under the best of conditions.

I have noticed that some cuts become more difficult to see over time, especially when they are lite cuts.

Another trick that I have seen is to put some blue painters tape down and then make your cut. You can then peel away the cut portion of the tape leaving one side in place. This provides a nice view image. A quick google search showed this link

http://www.finewoodworking.com/how-to/article/how-to-cut-perfect-dovetails-with-tape.aspx

Another trick that I have used with dovetails is to use my chisel to enhance the the line, at least along the top of the board while starting the cut. If I go in directly on the line and make a small channel on the waste side for the saw to sit in, it is very easy to start the cut because the saw just sits in it.

[Prashun Patel]

+1 on Andrew's painters tape tip.

For dark woods like walnut, you can mark the line with a fine point sharpie. If you require more precision, you can dust or color your knife mark with white chalk.

For light woods, I typically use a pencil.

[Susumu Mori]

Thanks Andrew.
Yes, dovetails are exactly what I'm talking about. These are great tricks!!

[Jerry Wright]

I was taught to make the line deep enough, then try to cut away 1/2 of the line. Hence it is an easily seen and deep scribe.

[Lee Schierer]

A .5 mm mechanical pencil makes a very thin line that would show up better.

[Bud Millis]

use a colored pencil to shade in the lines - shows up very easy then.

[Peter Quinn]

I sharpen a #2 pencil to a chisel point with sand paper and use that to finely highlight the scribe lines. For dovetails I really don't need to "see" the lines, I use the chisel as a feeler guage, make a very light tap at the scribe line, then back off the line to start chopping to the initial hits don't jump over the line or squeeze back into it and distort that fine depth line as tends to happen. The line is useful again after the bulk of the waste has been removed by sawing/ chopping as a stop for final paring, but this I usually do more by feel than sight.

[Susumu Mori]

Hi Peter,

I guess my problem in dovetail is to see the saw line for rip direction (two sides of the board) when I use a knife. Maybe I can just add a pencil line as you and other members suggested for that. Do you tap the chisel at the lines both on the end grain and for the side of the board? Or once a saw kerf is initiate at the correct location (in the end grain), do you just go down straight without visual guidance?

[Andrew Pitonyak]

I sharpen a #2 pencil to a chisel point with sand paper and use that to finely highlight the scribe lines. For dovetails I really don't need to "see" the lines, I use the chisel as a feeler guage, make a very light tap at the scribe line, then back off the line to start chopping to the initial hits don't jump over the line or squeeze back into it and distort that fine depth line as tends to happen. The line is useful again after the bulk of the waste has been removed by sawing/ chopping as a stop for final paring, but this I usually do more by feel than sight.


Another advantage to the "chisel to deepen", is that if the line is not exactly straight, the chisel will make it so for you.

[Andrew Pitonyak]

Hi Peter,

I guess my problem in dovetail is to see the saw line for rip direction (two sides of the board) when I use a knife. Maybe I can just add a pencil line as you and other members suggested for that. Do you tap the chisel at the lines both on the end grain and for the side of the board? Or once a saw kerf is initiate at the correct location (in the end grain), do you just go down straight without visual guidance?

So are you saying that you do not cut along the line on the backside of the board?

[Rod Sheridan]

SuSumu, try colouring them in with a pencil...........Rod.

[Chris Parks]

Use a hard carpenter's pencil and sharpen and shape it to a fine chisel point on the side of a bench grinding wheel. It will actually cut nearly as well as a knife and leave a mark that can be seen better and will leave a line as fine as a knife. A soft pencil will not work as the lead wears away too quickly.