Thread: Coping Saw Blade- Which Way?

I saw on the pull - the blade is in tension, not compression, and is effectively stiffer.

Regards from Perth

Derek

Mine is installed on the pull, a skilled carpenter friend had his on the push. I converted him to after getting his help for a day and trading saws.

But the real answer is a Collins coping foot on a jigsaw.

Same here; I cut on the pull stroke.

If you’re used to pushing and it works for you then I wouldn’t fret about it.

Originally Posted by Chief Tiff

I wouldn’t fret about it.

I see what you did there…

Originally Posted by Chief Tiff

Same here; I cut on the pull stroke.

+ one.

do whatever you like at the bench. If you build a coping jack and use it to cut something, then suddenly the idea that coping is usually done on the pull stroke will make sense.

OK...so I can't find a picture of what I'm talking about and don't want to dig mine out. Figure something similar to the mouth on a sawbench hooked to the bench.

The same jack is used with a fretsaw. Maybe I've got the wrong word for it.

Harpsichord and Violin Building in the 18th Century (3 of 4) - YouTube

Like this, a little circular hole in the middle and you can support cutting thin items on the pull where they'd be difficult to cut otherwise.

Originally Posted by D.W.

OK...so I can't find a picture of what I'm talking about and don't want to dig mine out.

Like a jewellers bench pin?

Originally Posted by jack620

Like a jewellers bench pin?

Yes!! like a bigger version of that sized for stock thick enough to use a coping saw.

Originally Posted by derekcohen

..... the blade is in tension, not compression, and is effectively stiffer....

Derek, the blade is held in tension by the frame & the cutting forces are transmitted to the frame exactly the same way whether the teeth are cutting on the push stroke or the pull stroke.

Would you put the blade in to cut on the pull stroke with this (a bowsaw built to take coping saw blades)? Coping blade.jpg

Occasionally I do, when I want the cut stroke to pull the work against a stop or a "birds-mouth" support though I very rarely use it that way, 99% of the time it's set to cut on the push stroke. And the reason I prefer to use it cutting on the push stroke is because it doesn't feather the line I'm working to.

There are no mechanical reasons for mounting the blade either way, it's a matter of personal preference & how the work is being supported. The blade will cut the same whichever way the teeth point but you, the operator, may find it easier or more comfortable to use one way or the other, & that's the "correct" way to have it..

My 2c
Cheers,

I like your thinking IanW and think that this is dependent upon the stiffness of the saw frame. If you're using a rock solid one like your timber one, I think the forces would be relatively even. If a cheap/crap saw that flexes significantly is used, I think that a pulling stroke would be more effective.

ie. When pushed, a flimsy saw frame may bend slightly when pushed. This could lead to a loss of applied tension onto the blade. Conversely, when pulled the tension is more stable as less force needs to be transmitted through the saw frame.

The conclusion I'd take from it is... use a good saw.

I would have thought Derek is right. The frame would compress slightly on the push stroke, expanding on the pull

The force isn't not exactly the same throughout the frame due to the handle not being in line with the cross beam. There would be some rotational force on the arm with the handle causing the effect.

The tension applied to the frame would make this small but is think it could be noticeable.

Regards

Adam

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Derek, the blade is held in tension by the frame & the cutting forces are transmitted to the frame exactly the same way whether the teeth are cutting on the push stroke or the pull stroke.

Ian, imagine the coping saw blade is a Japanese pull saw. The pull saw does not even have a frame. It may have a back, but it is easy to kink/concertina a thin Japanese blade if you push it. That is compression. When the saw is pulled back, the blade goes into tension. This adds stiffness.

Regards from Perth

Derek

No doubt there is a small amount of flexing of the frame on the push stroke, which would slightly reduce the tension on the blade. However, in roughly 45 years of doing it the “wrong” way I’ve never had a blade fall out. In fact, the setup is so rigid, it has never occurred to me to set the blade to cut on the pull stroke.

Jack, try it the "other way", and let us know what you find.

Regards from Perth

Derek