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morrisman
23rd August 2012, 01:35 PM
I have a query about power hacksaws

Is the power stroke

A: the forward stroke

B: the backward / reverse stroke

And, which way around is the blade fitted ? teeth angled towards the back or front

There is a definitive answer to this , my hacksaw does work but I may have the blade set up incorrectly

Mike

vincentvega
23rd August 2012, 01:45 PM
power stroke is forward just like a hand hacksaw.

Big Shed
23rd August 2012, 01:46 PM
Google is your friend:)

The Power Hacksaw (http://www.technologystudent.com/equip1/phcksw1.htm)

Stustoys
23rd August 2012, 01:46 PM
There is a definitive answer to this
Oh no there isnt.

Which way is forward?
Maybe "towards fixed jaw" or "away from fixed jaw" would be better?

I think its best to try and find out what the manufacturer of your saw intended as some are, some arent.

Stuart

p.s. lol hey Bg Shed, they have a foot in each camp. Anyone know what they mean by "ratchet systems"

vincentvega
23rd August 2012, 01:47 PM
I'm sure mine is set up cutting forwards - I will have to check now!

Big Shed
23rd August 2012, 01:49 PM
I'm sure mine is set up cutting forwards - I will have to check now!

I don't know as I don't have one, only a horizontal bandsaw.

Not only that, I'm only a "book machinist":p.

morrisman
23rd August 2012, 01:54 PM
OK

I have mine set up with the teeth angled forward , it seems to work fine . But, a textbook I have states that the power stroke is the reverse stroke , same as the animation described in Fred's wiki link .

Does the direction of rotation of the crank wheel change this theory ? eg, the crank rotating clockwise or counterclockwise .

Abratool
23rd August 2012, 02:00 PM
Mike
My Taiwanese machine cuts on the forward stroke, & I have the teeth cutting forward.
Reason being the machine has a small cam operated oil pot that makes the blade lift sightly on the return or backward stroke, thus extending the blade life.
regards
Bruce

Stustoys
23rd August 2012, 02:00 PM
I'm sure they all cut "forwards" the blade wont work "backwards"..... but which way is forwards on your machine?

p.s. Big sheds link shows both ways.
If you reverse one of these saws the lifter still works, you just have to turn the blade around. The power stroke is still the power stroke and the return is still the return its just going the other way :)

SurfinNev
23rd August 2012, 02:08 PM
Does yours lift the arm/blade on either forward or back stroke.? If it lifts on forward then teeth would face backwards and if if lifts on back stroke teeth would face forward.

Nev

Abratool
23rd August 2012, 02:09 PM
Mike
My Taiwanese machine cuts on the forward stroke, & I have the teeth cutting forward.
Reason being the machine has a small cam operated oil pot that makes the blade lift sightly on the return or backward stroke, thus extending the blade life.
regards
Bruce
When I am standing at the machine & in front of it, with the moveable jaw & vice screw closest to my feet, the cut is made as the saw moves towards the moveable jaw, & towards me (the operator)
regards
Bruce

morrisman
23rd August 2012, 02:19 PM
p.s. Big sheds link shows both ways.
:)

Yes it does , only adding to the confusion .

Stustoys
23rd August 2012, 02:21 PM
Does yours lift the arm/blade on either forward or back stroke.? If it lifts on forward then teeth would face backwards and if if lifts on back stroke teeth would face forward.

Nev
That just depends on which way the motor is going


When I am standing at the machine & in front of it, with the moveable jaw & vice screw closest to my feet, the cut is made as the saw moves towards the moveable jaw, & towards me (the operator)
regards
Bruce
So its backwards then? ;)

Bryan
23rd August 2012, 02:36 PM
Been lots of inconclusive debates on this. Seems that some machines can be set up either way. Mine cuts forward (lets call it the 'out' stroke for Stu), and I don't think it can be otherwise, though I haven't tried. Someone said his is meant to cut back(in). Was that Woodlee's Parkanson? What machine do you have Mike? Does it have lift?

SurfinNev
23rd August 2012, 02:37 PM
The fabricated saw I have, has a stroke of 125mm but does not lift arm/blade in either direction, so I suppose either way is right. It's one of those projects waiting for a rebuild so not actually used yet.

Just to confuse the situation more, what opinions are there as to which way the blade should cut? Push or pull stroke. I am leaning toward the pull stroke as there may be less chance of breaking the blade.

I will look at adding a lift feature sometime just to preserve the blade.

Nev

Dave J
23rd August 2012, 03:00 PM
I am pretty sure this was discussed in the thread below and there is another link in it about the same from memory.
http://www.woodworkforums.com/f65/parkanson-power-hacksaw-147063/


Dave

Stustoys
23rd August 2012, 03:03 PM
Hi Bryan,
Likely all you need to do is reverse the motor(and the blade of course). Now it cuts "in". (which would still be forward :P)



As to which way is correct, you'll have to ask the guy that designed your machine. I believe the timing of where the big end bearing* and the crank shaft are has a lot to do with it.

Stuart



*to use there car names

shedhappens
23rd August 2012, 06:01 PM
I have a Servian, it cuts on the back stroke.

And.......I think the cutting direction has a bit to do with how heavy the arm and slide are, if they are heavy like mine is then I don't think a course toothed blade would push to well.

Auskart
23rd August 2012, 06:23 PM
I have a Lotze and it cuts on the back stroke (blade in backwards), it appears to lift slightly on the forward stroke.

Burner
23rd August 2012, 06:37 PM
The power hacksaws I own have the advantage of a belt driven coolant pump, so It is easy to tell which way the motor should rotate,(if coolant isn't getting pumped, it's backwards!) then they all have a hydraulic lift so it is easy to tell which way the teeth should face, but stuffed if I can remember which way that is. If it wasn't raining and hailing outside I would go up to the shed and look!
I guess that's another good reason to wear out the blade and not break it, so you can put a new one on the same way as the old one, saves all that head scratching!

pipeclay
23rd August 2012, 07:44 PM
I have a query about power hacksaws

Is the power stroke

A: the forward stroke

B: the backward / reverse stroke

And, which way around is the blade fitted ? teeth angled towards the back or front

There is a definitive answer to this , my hacksaw does work but I may have the blade set up incorrectly

Mike
If something is not quite right just change it around,until you are happy with the way its cutting,cant be that hard.

vincentvega
24th August 2012, 02:20 PM
I had a closer look at mine last night and it does indeed cut on the back stroke. Mine is an old Australian made saw.

Big Shed
24th August 2012, 03:34 PM
My horizontal bandsaw also cuts towards the back.