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jr45acp
06-09-2012, 10:45 AM
In my 63 years, I've always had trouble making a straight cut with any type of hand held saw(rip, cross cut, hack).

I either dreamed or once heard that reversing the blade on a hacksaw so the cut was made on the draw stroke has the potential of eliminating, to whatever degree, this problem.

I've got to make a number of cuts on a piece of brass sheet that is 0.020". If the blade reversal has potential that is what I plan on doing. Of course I'll make my cuts in a manner that gives me some cleanup room to the final desired position, and I plan on using a 32 tooth blade.

Does any of this sound reasonable?

Thanks

A.K. Boomer
06-09-2012, 10:52 AM
It kinda does in theory due to pulling being "self aligning"

but I don't believe it works this way in practice --- there are far more joints than just your wrist on the hacksaw blade - your shoulder elbow and even your body stance comes into play and this is not self aligning...

There's another huge factor that you will be fighting --- Pushing the blade in the geometry it's designed for is "self engaging" another words your cutting pressure exertion is compounded --- not so with pulling - it's a leverage thing from where the power is coming from to where the works getting done, and pulling sucks...

It's just practice --- build a deck or house add on with a high quality hand saw and you would not believe how good you can get with 2 by 4's,

I can make a cut that is every bit as good as a skill saw.

It's a constant focus with every stroke - the thing is - is if your start to mess up you have time to correct it unlike a skill saw...

Stepside
06-09-2012, 11:03 AM
For .020 Brass you want to use a Jewelers saw and a V-block. The saw is held so the blade is vertical and cuts on the down stroke. The V-block supports the material.

jep24601
06-09-2012, 11:04 AM
In my 62 years I don't think I have managed a straight saw cut by hand but with a Japanese pull saw I have come very close to it.

With a Japaneses pull saw one thing that seems to make a difference is that you can hold the saw right at the end of the handle, stand back and pull while eyeing the alignment. Also you can't quite put all your weight behind the saw like when you are pushing so you tend to go more gently all the while eyeing your alignment.

A.K. Boomer
06-09-2012, 12:02 PM
Either way your going to have to focus on every stroke --- so you might as well use the one that gives you the biggest bang for the power output and that is pushing...
even if you want to keep the bites small as this will allow you to use far less muscle and concentrate on control...

It really is simple --- you only have two things to follow - one is the scribed or markered line and the other is keeping the blade 90 degree's to the board or whatever, what will aid you in the latter is starting the cut diagonal to the piece -- this way you almost can't screw up because your scribed or markered line will help you with the 90 degree rule...

mickeyf
06-09-2012, 12:16 PM
Number one: Saw must be perfectly sharpened. This of course would be much easier to achieve with a 12 tpi wood saw than a 32 tpi hacksaw if not for the fact that you can buy new, high quality blades and forget about resharpening them.

Number two: The wider the blade, the less it will be able to get out of alignment in the cut. A 1" wide blade from a power hacksaw will give much better results than a regular 1/2" wide blade designed for a hand hacksaw. If you can find something even wider, so much the better.

Number 3: Practice. Even if you only do a few test pieces before the one you actually care about rather than taken 30 years to master it, you'll get better results than otherwise.

jr45acp
06-09-2012, 12:35 PM
Gentlemen, thanks for the feedback. In all honesty, I suspected the responses provided would be the case. So, I'll proceed as advised and leave some latitude for clean up with a file. Then again, the local trophy shop has a shear they use to cut these brass sheets and I probably could just get it cut to size for a few bucks.

Regardless, thanks.

Mcgyver
06-09-2012, 12:57 PM
I'd get that to on a shear if straight, jewelers saw a v board as mentioned if nature of cut prevents shearing. imo a cut with the jewelers saw will need some filing to the scribed lines to resembled something straight. If no shear is available, I'd still go with the jewelers saw and file, easier to control than a hacksaw

if you need an example: http://bbs.homeshopmachinist.net/showthread.php?t=13891

on cutting straight in general, ie woodworking, I'm far from an expert but lack of power tools (due to # of machine tools) means i cut and dimension wood by hand when i have to. This is what I found works. Draw your lines. Have a meeting with yourself and declare, self, this cut will remain perfectly square and along the lines if I only do one thing: move the blade unerringly in the same plane. Your muscles won't naturally do that but by going slowly and concentrating on bring the arm forward and back exactly in the same plane (as best you can) you'll improve. you need a good sharp saw and practice as well of course.

Seems like a stupidly simple thing but consciously focusing on the motion being in the same plane is what took me out of the crooked saw club.

Interested to here what the more experience straight cutters have to say on staight cutting tips and tricks

danlb
06-09-2012, 01:07 PM
A couple of other things come in to play here. From my experience....

If you wear glasses, they may gently distort your view, making a straight line seem crooked and vise-verse. Especially true if they correct for astigmatism.

Some of us can't really tell when we are at 90 degrees when cutting. 80, 85 and 90 degrees all look alike when I'm at the wrong end of a saw or drill. I find that I can do much better with a support block that is cut to the angle that I want to match. That gives me a visual cue when I'm off.

Dan

lakeside53
06-09-2012, 01:26 PM
All the Japanese saws cut on the pull stroke. Except for my Sandvic/Lenox hacksaws, I tossed my American/Brit saws 25 years ago and never looked back.

Because of the tension in pull, they have a narrower kerf and cut beautifully.

And... the finish saws are typically "mirror finish". This way you line up the reflection of the wood on the saw (run your eye though the far edge. saw and continue) and get a perfect right angle. This is a mystery to most American owners ;); I learnt that while in Japan. You almost never see a square or a pencil.. so obvious when you see it..

bytewise
06-09-2012, 02:40 PM
One thing that helps you make straight cute is to position your body so that your shoulder, elbow and hand are all in the plane of the cut you want. Then practice not wobble when sawing. Look at the blade, not the saw frame. The blade may not be well aligned in the frame. It would also be good to practice on some scrap.
Have fun!

JCHannum
06-09-2012, 03:56 PM
Another tip is to scribe two lines, one at the cut line and one about double the kerf width or so outside of that. Keep your cut between the two.

Dr Stan
06-09-2012, 04:12 PM
the local trophy shop has a shear they use to cut these brass sheets and I probably could just get it cut to size for a few bucks

That's exactly what I was going to recommend. Actually a heavy duty paper cutter will handle .020" brass.

darryl
06-09-2012, 07:08 PM
Something that thin calls for shearing, not cutting with a hand saw. But in general, sawing straight by hand is something that takes a while and patience to learn. The thought about getting all the body parts lined up correctly is right on. It's like shooting pool, in a way.

Boomer, I'm sorry about the poor condition of your skil saw. I've been cutting with a hand saw for decades and have gotten pretty good at it, but I can't reproduce the look of a skil saw cut- at least one that' working properly anyway :) If you can do that- well my hat's off to you sir.

I like pull saws for various things, but they won't fully replace the normal hand saws. I like the fact that they are normally extremely sharp and have an easy cutting action, and that does help to make the cut smooth and straight. On a job site cutting 2x4s- personally I'll stick with the normal hand saw.

Guido
06-09-2012, 08:20 PM
I quit sawing wood about 63 years ago, when Uncle Hershall caught me in his wood shop, using his tools to saw a board. I was real proud of myself and thought he was too, as he stood there, watching.

Then he walked away, mentioning that "I sawed like a girl".

--G

Stepside
06-09-2012, 09:22 PM
When learning to use a hand saw whether it be for firewood or barn building my dad would say "get you butt behind you". Now I knew where my butt was , but I would look anyway and then the sawing would "go to hell in a handbasket". This would up the volume of "get your butt behind you" and the sequence would repeat until he would finally give up and grab the saw to finish the job. All he wanted was for me to be lined up so my sawing arm could pass my body in a straight line.

When engraving some brass the other day I engraved the cut line as well as all the detail. This gave a easy line to follow with the jewelers saw. If the brass is a rectangle or a series of straight lines I use a sheet metal shear for the cuts.

Don Young
06-10-2012, 12:23 AM
Can anyone actually cut .020" brass with a 32TPI hacksaw? Seems to me like you would need 100-150TPI to have 2 or 3 teeth in the cut. Of course you could sandwich the brass between something thicker.

Ian B
06-10-2012, 08:18 AM
John B,

First thing that helps is a decent hacksaw frame. I struggled for years with a lousy one, I now use an Irwin frame, like this one:

http://www.google.com/products/catalog?q=irwin+hacksaw+frame&hl=en&prmd=imvns&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&biw=1920&bih=1119&wrapid=tlif133932995349310&um=1&ie=UTF-8&tbm=shop&cid=16370164548701337275&sa=X&ei=9oDUT7SWC-ng2QWFgb28Dw&ved=0CEwQ8wIwAA

Others will have their favourites, but I like this one.

Next, when you make several cuts, do they all deviate in the same direction, or are the results random? If they're all the same (as mine tend to be), easy enough - just aim to make the cut at a lop-sided angle, the opposite direction to how your cuts normally wander off.

Works for me.

Ian

lakeside53
06-10-2012, 12:39 PM
I like pull saws for various things, but they won't fully replace the normal hand saws. I like the fact that they are normally extremely sharp and have an easy cutting action, and that does help to make the cut smooth and straight. On a job site cutting 2x4s- personally I'll stick with the normal hand saw.


I have a 2 sided Japanese pull saw that cuts 2x4 in about 4-5 pulls. I use that so much when I'm up in the rafters or trimming in awkward spaces. These blades are thicker than the finishing types.

A.K. Boomer
06-10-2012, 02:00 PM
Yeah lets face it though there's some 2by4's that are more closer to balsa wood than fur...

I built most all my stuff with a Made in Sweden Bahco hand saw --- conventional and not even close to full size - just a small/medium length,

I can remember almost getting through a 2by4 in three swipes...

it was by all means a "light" 2by4 but what a handsaw those Bahco's are, just good quality all around...

kf2qd
06-10-2012, 03:15 PM
If you can't walk straight going forward, I don't see how walking backwards is going to help...

I think the reason for the pull stroke with a hack saw is it puts less force into the part being cut, okay for small work pieces and fragile parts. Related to body mechanics and such.

A.K. Boomer
06-10-2012, 03:22 PM
I think the reason for the pull stroke with a hack saw is it puts less force into the part being cut, okay for small work pieces and fragile parts.


In which it could be argued to just get a finer tooth blade and use the saw in the way in which it was designed for...:)

Bob Fisher
06-10-2012, 05:16 PM
Ditto to Don, you need a much finer blade and a jewelers saw frame cutting on the pull stroke. Jewelers saw blades come in very high tooth counts. Your local big box store, however will not be a source for these blades. McMaster Carr should be a good source for a quality blade, and amazing delivery. Bob.

Mike Nash
06-10-2012, 06:53 PM
Practice only goes so far. For some of us, this is more what it feels like:

http://www.dailyhaha.com/_pics/no-artistic-ability.jpg

A.K. Boomer
06-10-2012, 07:36 PM
so true ---- good job on getting the number of digits right though,

or were you trying to draw two hands?:o