Pencil l ines or scribe lines

[Eric.]

4 minutes ago, Tom King said:

I must not be visualizing this correctly.  Are you talking about marking the pins after the tails are cut?  That's what I was talking about marking the second part by the first part, which has already been cut.  If the pin is scribed by the previously cut tail, the scribed line is on the part that needs to be left for it to fit perfectly.  If the scribed line had zero width, it would work, but if it had zero width, you couldn't see it.

What I'm talking about is a pencil line maybe a couple of thousandths wide.  In order for the joint to fit perfectly, that couple of thousandths needs to be left on the end of the pin.  It's easier for me to do that than to cut right outside the indention left by the knife.

It's hard to have a discussion about it because language and description become limiting factors.

The best way I can explain it is like thinking about it the same way you do an inlay.  When you excavate the negative space, you hog out exactly up to the line, then stop.  It's exactly the same way when paring to a knife line.  Up to it, but no further.  And then it is an exact fit to the positive that created the line.

[Tom King]

i can see how that would work, but that's not putting the chisel in the knife line.    Putting a chisel in the knife line doesn't make sense to me on the second part. On the first part, it doesn't matter.   Paring to the line, and leaving it does make sense.  I'm just used to doing it my way.  I can't say how many thousands of saw cuts I've made though, so I don't even think about what's going on.  I just watch the cut line on the finish side.

[Ronn W]

On 8/4/2017 at 8:25 AM, Gilgaron said:

I still use a small mechanical pencil for some things, but largely have switched to a 2mm lead holder, which is for drafting.  You can extend the lead out to reach into weird spots and there's also plenty of colored lead available for them.  In use it is a very functional cross between a wood pencil and a mechanical pencil. 

OK you are giving away your age.  I have a bunch of lead holders but any under 30 doesn't know what they are.

On 8/4/2017 at 1:55 PM, Tom King said:

My problem with scribed lines is with the second piece.  Regardless of which part you cut first, the second part needs to have the line left. I take the line on the first piece, just to get rid of it.  There is more guess work for me deciding exactly where you start the "leave" to a scribed line, than to a marked line.  I cut everything first shot with a saw.  I even plan on some paring with tenons, but anything cut with a saw should be cut right to start with.

I'll try to take some pictures this weekend.

Are you saying that if you use a scribe line on the second piece and pare with the chisel in the scribe line that the fit will be too tight?  I thought the whole idea of a scribe oine was that's where you put the chisel blade.  Or have I misunderstood you?

[RichardA]

I believe that what's being said is.. on the second piece the scribe line shows exactly where the first piece ends. If you take that line with your chisel, you have just made a loose fit. Leave the line and chisel up to it, and your fit should be snug.

[wtnhighlander]

I agree with Richard, the caveat being, how do you chisel up to an infinitesimal scribe line, without 'taking' it?

[Ronn W]

I am going to pracfice some more anyway so I will try both pencil lines and scribe lines.

Seems that if the scribe line is infinitesimally small, the chisel in the scribe line should give a good fit  I have a feeling that once you get down to "infinitesimal" the skill of the wood worker becomes the limiting factor.  Are we having fun yet?

[Tom King]

18 hours ago, Ronn W said:

OK you are giving away your age.  I have a bunch of lead holders but any under 30 doesn't know what they are.

Are you saying that if you use a scribe line on the second piece and pare with the chisel in the scribe line that the fit will be too tight?  I thought the whole idea of a scribe oine was that's where you put the chisel blade.  Or have I misunderstood you?

I meant that the fit would be too loose.  You have to leave the whole line on the second piece.  It doesn't matter whether you take the line, or leave it on the first piece, but the second piece has to have the line left.  You can even have an interference fit by a thousandth or two on soft woods, but a thousandth too small, and you have a loose fit.  That's why I don't scribe a line on the second piece.

I had a busy weekend, with a house full of company, so didn't get any pictures of woodwork, but will still try to remember to take some pictures sometime this week.

The pencil lines matter.   I use pencils that leave a TINY line just from sharpening in a crank sharpener, and the point is not fragile.

[Coop]

On ‎8‎/‎7‎/‎2017 at 0:42 PM, wtnhighlander said:

I agree with Richard, the caveat being, how do you chisel up to an infinitesimal scribe line, without 'taking' it?

That really is a word!!

[derekcohen]

Try using my blue tape method ...

Half blinds:  http://www.inthewoodshop.com/Furniture/HalfBlindDovetailswithBlueTape.html

through dovetails:  http://www.inthewoodshop.com/Furniture/ThroughDovetails3.html

 

Regards from Perth

Derek

 

[RichardA]

I like your solution Derek. That will help anyone except maybe Rob Cosman.        Regards from Tennessee     Rick

[derekcohen]

Hi Richard

Actually, Rob has taught my method on his course (and credited me).

Regards from Perth

Derek