Recommended SFM for power hacksaw?

[Jimmer12]

I'm looking to build a power hacksaw and am trying to find the recommended SFM for hacksaw blades. Does anyone have this information?

[RussZHC]

http://freetechnicalcharts.com/Power_Hack_Saw_Guide.php

http://www.jjjtrain.com/vms/other_pwr_hack/other_pwr_hack_03.html

first one is more a stroke rate, second just gives a range (40 to 150 sfm depending on materials etc.); Starrett may have something deeper in their files...found the hole saw recommendations pretty quick but no joy on the power hacksaw blades

[sasquatch]

Post some pics Jimmer- interesting project.

[Mcgyver]

I'm looking to build a power hacksaw and am trying to find the recommended SFM for hacksaw blades. Does anyone have this information?

not sure why it would be different for any other cutting speed guidelines? Recommended cutting speed is function of blade material and what you are cutting.

I'd think the constraint was more going to be a reasonable # strokes per minute such that it didn't shake itself apart....ie if you ran a 6" stroke machine 100fpm (bimetal blade cutting steel) that would be 200 strokes per minute!

[Jimmer12]

not sure why it would be different for any other cutting speed guidelines? Recommended cutting speed is function of blade material and what you are cutting.

I'd think the constraint was more going to be a reasonable # strokes per minute such that it didn't shake itself apart....ie if you ran a 6" stroke machine 100fpm (bimetal blade cutting steel) that would be 200 strokes per minute!

Thats my point exactly, I am trying to work out a balance between strokes per minutes and SFM if I can, as I would like to set it up using a stepped pulley for various materials.

Russ, I will be sure to post some photos but right now this project is at about as juvenile a stage as it can get. So far it consists of me remembering I had an extra 1/2hp baldor motor in my garage and thinking "what can I do with that?"

[sasquatch]

Jimmer, just off the top of my head, , from what i remember seeing , around 60 strokes per minute seems about correct.

[Black_Moons]

not sure why it would be different for any other cutting speed guidelines? Recommended cutting speed is function of blade material and what you are cutting.

I'd think the constraint was more going to be a reasonable # strokes per minute such that it didn't shake itself apart....ie if you ran a 6" stroke machine 100fpm (bimetal blade cutting steel) that would be 200 strokes per minute!

100 strokes per minute.
As a stroke is 6" of movement forward and 6" back, its effectively 12" of movement per stroke
(ie: It has to go twice as fast as the stroke count unless it has uneven forward and reverse stroke speeds)
And 100FPM would be for a good bimetal blade, sure. The older carbon steel blades likey want more like 60FPM, or the 60SPM that sasquatch recommended.

[sasquatch]

I think Jimmer needs to post what length of blade he will be using first?

[Jimmer12]

I think Jimmer needs to post what length of blade he will be using first?

I am thinking of using a 12" standard hacksaw blade as opposed to the "powersaw" blades, as I can get them anywhere for a few bucks a piece, rather than special ordering the powersaw blades at a much higher price. I am thinking of using about a 6" stroke, but will be able to visualize that better once I start modelling it in the computer.

[sasquatch]

Agreed, power hacksaw blades are getting hard to find!!
If you find some the dealer will order them for you, IF you buy a whole box!!

[sasquatch]

jimmer, try this site, there are a number of builds and retailers there with saws using a 12 inch reg blade.

htpp://www,model-engineer.co.uk/

[Jimmer12]

Thanks for the hint Sasquatch! I will spend some time on that site tomorrow checking it out and getting some ideas down in Solidworks.

[HSS]

ya know, power hacksaw blades are thicker and wider than regular blades. There may be a reason for that.

[Jimmer12]

ya know, power hacksaw blades are thicker and wider than regular blades. There may be a reason for that.

Yes I am aware of that, and I am also aware that most "real" power hacksaws are 2hp give or take. I only have a 1/2hp motor, so I will be building one that is lighter duty, less pressure on the cut etc. It's for home use in a hobby machine shop anyway, so I don't really care if it takes longer to cut, or if I have to replace a $2 blade more often.

When I have the space and money, I will invest in a bandsaw with hydraulic downfeed and coolant for the big chunks of metal to cut.

[RussZHC]

Apples and oranges...try this http://www.youtube.com/watch?v=P5Tu_zoO828

for what it is worth there are LKS (IIRC the company name/acronym) scattered all over Canada, seldom does more than 2 weeks go by on Kijiji that one is not up for sale...don't recall if they use a regular hacksaw blade or one from a power hacksaw...just saying, it maybe cheaper or give you another idea as to design though at some point they are all sort of similar, I think...if you come across a Sears version, you could pay more there is a bit of a collectors market for those...

For what some ask for that style of hacksaw you are often much of the way to a used metal cutting bandsaw...