Correct use of marking knife

[ajbell]

Hi Guys

When using a marking knife do you make the cut with a series of stokes to deepen the cut as you do with a marking gauge or with a single deep stoke?

I am having issues marking using a square as I end up with a set of lines instead of a single line as the square seems to move due to the side pressure of the knife on the square.

Is it just a matter of practice to get the technique correct?

Andy

 

[AndyT]

Andy, I'd recommend that you

a) use a knife with a single bevel, flat side against the square (so no side pressure)

b) get it seriously sharp, so you only need one stroke.

 

[ajbell]

andy

Thanks for the reply.

I just got a single bevel jap marking knife today but cant seem to avoid the square moving - I may just be trying too hard and applying too much force.

Andy

 

[AndyT]

The jap knives are excellent. Assuming you are right handed, and the face edge is towards you, use your fingers of your left hand to press down on the blade of the square, and the thumb to push the stock away from you against the wood.

Oh and remember to position the knife where you need it first, and then slide the square along to meet it.

 

[ajbell]

Andy

Ah ha!
that is much better - thanks!

I had the face away from me and was using the the fingers of the left hand to hold the stock and the thumb to hold the blade so I was cutting away from the stock rather than in your description were you cut towards the stock.

That is much easier to control - is the way I was doing it just totally wrong?

andy

 

[AndyT]

Whatever works is right!

 

[mr grimsdale]

Try a pencil. You can do all necessary marking with a pencil. HB, 2H etc
You don't need a knife unless you really need a starter sharp edge as for dovetail shoulders.

 

[woodbloke]

Try a pencil. You can do all necessary marking with a pencil. HB, 2H etc
You don't need a knife unless you really need a starter sharp edge as for dovetail shoulders.

Sorry Mr G...just plain wrong and poor advice for someone struggling to do it the right way. A single bevel marking knife used with the appropriate pressure (for either a heavy or light line as required) is always more accurate than a pencil - Rob

 

[Derek Cohen (Perth Oz)]

Whether I am using a heavy duty knife to score a deep line on a face or side, or a dovetail marking knife on end grain, I prefer to make several light strokes instead of a single heavy stroke. This is particularly so if there is any risk of the grain threatening to guide the blade away from the line. Then very light strokes until you create a kerf. Only then can you make your strokes heavier.

With regard dovetail knives, I prefer a thin blade that has some flex in it. You can run it against the side of the tail and add pressure (via the bend) causing it to hug the tail wall.

Unless your pencil line is very thin, and is reliably so, marking in pencil must be seen to be a temporary method, certainly not accurate enough for tight joints. You avoid hit-and-miss sawing with a thin knifed line.

Regards from Perth

Derek

 

[ajbell]

Hi Guys

Thanks for all the advice.

I will continue with the knife and use light multiple stokes.

There also seems to be a tendancy for the knife to try and cut into the metal square - I did read in DC's book that this can be a problem so I guess I need to get the angle and pressure correct to avoid this.

Would you angle the knife in the vertical plane so that you were cutting with a short edge near the tip of the blade or lower it down so that the entire cutting edge was in contact with the wood?

Or am I over complicating the entire process?

Thanks again

Andy

 

[AndyT]

Hi Guys


Would you angle the knife in the vertical plane so that you were cutting with a short edge near the tip of the blade ?

Andy

Yes!

 

[mr grimsdale]

Try a pencil. You can do all necessary marking with a pencil. HB, 2H etc
You don't need a knife unless you really need a starter sharp edge as for dovetail shoulders.

Sorry Mr G...just plain wrong and poor advice for someone struggling to do it the right way. A single bevel marking knife used with the appropriate pressure (for either a heavy or light line as required) is always more accurate than a pencil - Rob

For most purposes a knife is the wrong way IMHO. For a beginner a pencil is much easier, not least because a beginner will have difficulty with a knife (as with our OP), won't necessarily get it in the right place to start with and won't find it as easy as it is supposed to be, to cut against accurately.

 

[woodbloke]

Try a pencil. You can do all necessary marking with a pencil. HB, 2H etc
You don't need a knife unless you really need a starter sharp edge as for dovetail shoulders.

Sorry Mr G...just plain wrong and poor advice for someone struggling to do it the right way. A single bevel marking knife used with the appropriate pressure (for either a heavy or light line as required) is always more accurate than a pencil - Rob

For most purposes a knife is the wrong way IMHO. For a beginner a pencil is much easier, not least because a beginner will have difficulty with a knife (as with our OP), won't necessarily get it in the right place to start with and won't find it as easy as it is supposed to be, to cut against accurately.

In some cases recently Jacob, much to my surprise I've found myself agreeing with you, which is pleasant. On this occasion though I can't...you are wrong, simple. I was a woodwork teacher for 20 years and Yr 7 children were never, ever taught to mark out with a pencil, always a marking knife. This was the first time that many of them had ever used woodworking tools of any sort, so the learning curve was steep, but by quickly learning the correct way to use the tool (in this case the marking knife) as our OP is doing, there was rarely a problem (and if it was it was usually one of small hands and inadequate manual strength)
Please put your hands up and accept graciously that you are wrong on this occasion (you probably won't do :roll: ) as I'm not saying anything further [-( :-# - Rob

 

[PerranOak]

b) get it seriously sharp, so you only need one stroke.

I find that if it's too sharp, I can't see the resulting line!

 

[bugbear]

There also seems to be a tendancy for the knife to try and cut into the metal square - I did read in DC's book that this can be a problem so I guess I need to get the angle and pressure correct to avoid this.

I find a tiny (and I mean tiny, verging on imperceptible) back bevel on the flat side of the knife is enough to prevent this, as long as the flat bevel of the knife is low enough to have a substantial contact with the straight edge.

BugBear

 

[mr grimsdale]

.....
In some cases recently Jacob, much to my surprise I've found myself agreeing with you, which is pleasant. On this occasion though I can't...you are wrong, simple. I was a woodwork teacher for 20 years and Yr 7 children were never, ever taught to mark out with a pencil, always a marking knife. This was the first time that many of them had ever used woodworking tools of any sort, so the learning curve was steep, but by quickly learning the correct way to use the tool (in this case the marking knife) as our OP is doing, there was rarely a problem (and if it was it was usually one of small hands and inadequate manual strength)
Please put your hands up and accept graciously that you are wrong on this occasion (you probably won't do :roll: ) as I'm not saying anything further [-( :-# - Rob

Nothing is that simple! It's a matter of opinion.
I was taught at school to use a knife too. Difficult, but I think this was to ensure a clean edge as sawing to a pencil line is even harder for kids. But with increasing confidence sawing to a pencil line becomes easier.
Pencil for marking up is much easier, is correctable and doesn't leave a permanent mark. But it is slightly harder to get a clean edge, but not impossible so it's a trade off against speed and ease of use.
But when you start looking at trad work you find knife marks for DT shoulders - on cheap work because it helps to get a clean edge.
Also I've found knife marks on one side only of window and door stiles and rails, but carried round with pencil. My theory here is that the knife marks were taken from the rod by a senior craftsman but continued in pencil by the junior. This would ensure that they were in the right place and indelible but leaving the rest of the marking out to a junior, using a pencil because it is easier.
So there is a place for knife marks - but not everywhere and not simple. The two very good reasons for not using a knife are that it is difficult to correct a mistake and it may be difficult to remove the mark from the finished work.

 

[bugbear]

b) get it seriously sharp, so you only need one stroke.

I find that if it's too sharp, I can't see the resulting line!

You're confusing a sharp edge with a low bevel angled edge.

In the case of marking knives (and marking gauges with knives) I find a steep bevel, sharpened well, cuts nicely and leaves a good visible mark. Blunt is no use to anyone.

If you want a true cutting gauge (e.g. for veneer strips) you might want a spare blade, sharpened at a lower angle.

BugBear

 

[PerranOak]

Yes, I see.

All the more important to have the bevel on the correct side then!

 

[bugbear]

Yes, I see.

All the more important to have the bevel on the correct side then!

Absolutely.

BugBear

 

[JoinerySolutions]

From 27 years in the trade the rule has been pretty much the same.
Marking knife for cut edges, bevel to the waste side: i.e. tenon shoulders.
Double pinned Marking guage for tenon and mortice widths.
Single pinned Marking guage for trenching depths: i.e. hinges and groove depths in door lining heads.
Cutting guage for repetative across grain marking of cut lines that might also be done with a marking knife: i.e. shoulder lines of dovetails.
These all really relate to hand wrought joinery and furniture work, it is seldom required to use more than a pencil for machining operations as most cutter heads have scribing cutters that do the work of a knife or guage prior to the cutter or blade addresses the timber, even the design of the hollow mortice chisel does this job.
Most joiners and cabinet makers use an engineers square for marking out as the blade on it is thicker and not prone to movement as found in some adjustable carpenters squares.
Hope this is of help, tried to cover as much as possible with clarity.
ATB Rob.
Edit:- Forgot to mention that the need to use an incised mark in marking out is to reduce or negate splintering and break out in the finished piece when sawn or chiseled with hand tools.