Leveling and Tensioning

A forum about crosscut saw filing

Re: Leveling and Tensioning

Postby da yooper » November 9th, 2012, 12:11 pm

Howdy. I came across a dog face hammer, but haven't seen this style of hammer talked about. I know they are made for saw and knife work. Are there situations were a dog face would be more appropriate than a cross face for leveling or tensioning? Thanks All. Tom
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Re: Leveling and Tensioning

Postby Starling_Saw » November 10th, 2012, 6:26 am

Dog Head and Round face Hammers, I have found to be used more on small round lumps and for tensioning a saw plate where I want the tension to expand the plate even, all around the area of the strike. The Cross face hammer is used for hammering long creases, ridges, and for expanding the saw plate directionaly.
John
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Re: Leveling and Tensioning

Postby da yooper » November 10th, 2012, 9:57 am

Starling_Saw All this is great info, and extremely helpful!! One last question for a bit?? When you are tensioning a saw, and hammering on both sides of the plate with a cross face hammer. You mentioned to use the vertical face on one side and the horizontal on the other in a checker pattern. Do you make note of which side vertical/horizontal is being used, and only use vertical/horizontal on noted sides?
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Re: Leveling and Tensioning

Postby Starling_Saw » November 10th, 2012, 10:50 am

When using a crossface for tensioning, I use the vert. on one side and the Horz. on the opposite side. I strike the same place on each side. Perhaps if I used a round face like a Dog Head, I wouldn't have to think about keeping the vert. on one side and Horz. on the other. I would just focus on striking the same place on each side. If striking only one side, you would cause the plate to become unlevel and the plate wouldn't hang straight. You are expanding the metal without bending it. Comparison would be like a fruit jar lid where it can pop back and forth a little bit. But with that in mind, you never want so much tension in a saw where it would pop back and forth though. Only enough where it is visable when bending the saw. If enough tension is in plate when you pick up the saw in the mid section, the ends will not droop as much, more stiffness is what we are wanting in a saw without adding the weight of a heavy thick plated saw.
As for the checkerboard pattern, I'm discribing the addition of tension of the plate. Start with a single line across the area to be tensioned if more is needed start another row of strikes, but staggered between the first set or row, even across the width and the length of the area to be tensioned.
John
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Re: Leveling and Tensioning

Postby da yooper » November 12th, 2012, 11:02 am

Thank you Starling_saw. I'm getting the hang of it slow but sure. There always seems to be a sweet spot in the plate. The difficulty is recognizing it! Tom
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Re: Leveling and Tensioning

Postby Diabolo » November 22nd, 2012, 7:26 am

I'd like to know why crosscut saws have to be tensionned.
Tensionning, which is stretching the body, is usefull on handsaws for 2 reasons:
- when sawing a long time, the toothline warms a little, which can make it unstable (wavy). Stretching the body makes the toothline under traction, which compensates.
- it helps correcting the track. By pushing the tote sideways a little, the section of the blade becomes an arc, helping "turning".
But a crosscut saw is much stiffer and thicker. And the teeth are long, far from the body.
So I don't know the reason of getting a tension is this kind of saw.
Could anyone explain ?
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Re: Leveling and Tensioning

Postby Jim_Thode » November 22nd, 2012, 8:05 am

Diabolo,

I have the same question. I understand that hammering is needed on crosscut saws to level, flatten or straighten the blade. If a crosscut is manufactured with tension or it develops from some unforeseen cause then hammering to take the tension out of a crosscut blade makes sense to me.

Tensioning or hammering circular saw blades to compensate for the different stresses caused by rotating at speed and tensioning or hammering any saw that the parts of the blade operate at different temperatures makes perfect sense to me. I don’t see any changes in stress due to speed or temperature in a crosscut saw that would require it to be tensioned.
In all the documentation I can find there is no old or new literature that requires or explains tensioning a crosscut as a normal maintenance requirement. Does anyone know if any references?

Like I said the only reason I see for messing with the tension in crosscut saw is to remove it. However, I’m all ears for different points of view.

Jim
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Re: Leveling and Tensioning

Postby Diabolo » November 22nd, 2012, 9:45 am

Yes Jim, I completely agree with you. Anyway, tensioning seems to be part of the normal fabrication process as far as every saw I own, either in NOS or clean condition, have the caracteristic tracks of roll-tensioning.

Yves
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Re: Leveling and Tensioning

Postby Double Ott » November 22nd, 2012, 12:05 pm

Let me as a new guy ask a question. In the saw picture above there appear to be waves or dips in the steel. You refer to them as "caracteristic tracks of roll-tensioning" Are you suggesting that these be hammered out and smoothed out?

What would happen if the saw was used as is? Chatter? Flexing? I'm trying to understand what going on here. Sorry, I guess that's two questions.

Thank you, Double Ott aka, Tom
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Re: Leveling and Tensioning

Postby Diabolo » November 22nd, 2012, 12:35 pm

No worry !I'm lucky, this saw is perfectly flat. I'm just in the process of cleaning and sanding it. What you take for irregularities is just the reflection of the lights and the flash on the sanded areas.

Yves
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