# A hack saw attachment for the lathe?



## Bob Kelly III

I've been thinking about making a power hacksaw attachment for my lathe.... just to cut through big chunks of steel..... I don't have a chop saw or a metal cutting bandsaw
just a reciprocating saw.... and I use it all the time... but I was thinking that I could make a power hack saw attachment for the lathe sense my lathe can go extremely slow
..... has anyone already done this ?  is it worth the effort ?  i have a feeling it would be thrown in a corner and never used ! LOL..... but I could make the stroke adjustable and have it clamp to the chip pan and just chuck up the crank in the lathe and turn it on.......
what do you guys think ?
....
Bob.......


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## JimDawson

Never seen that done before, but sounds interesting.  I'll be waiting for the build thread.


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## MontanaLon

Be sure to put a stop on the lower end. Would be tragic to turn it on and come back to find it cut through the bed.


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## darkzero

Sounds like quite the project but I too would love to see what you come up with! If I didn't have a bandsaw I'd probably just get me a cordless portaband. That way it would be useful for other things also.


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## T Bredehoft

Just hold the  saw still and let it slowly drop onto the turning part. (don't worry about the bed, it won't be turning)

_Edit:_ correct typo


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## Winegrower

It might be easier to hacksaw some parts off rather than parting.   Not a bad idea, Bob.   Hope you will pursue this a bit more.


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## MontanaLon

T Bredehoft said:


> Just hold the  saw still and let lillt slowly drop onto the turning part. (don't worry about the bed, it won't be turning)


That amounts to single point cutting with a 12" tool. It wouldn't cut for long and wouldn't cut well as there would be no where for the chip to escape the gullet of the 1 tooth that is engaged in the work.


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## Bob Kelly III

T Bredehoft said:


> Just hold the  saw still and let lillt slowly drop onto the turning part. (don't worry about the bed, it won't be turning)


LOL that don't work worth a darn I've tried it ! trying to part off things.... it takes way too long !.....Bob.......


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## Bob Kelly III

a friend of mine suggested a small engine crankshaft and rod as the part you chuck up in the lathe ...a bar from the rod to a hinged lever to adjust the stroke of the hack saw....   i thought that was a clever idea ! might cut down on allot of vibration by doing it that way !
.....
it's obviously gott'a have some sort of table to it that is solidly fixed to the lathe, maybe clamped to the chip pan with short legs. and welded on vice grips !
.....
it also needs a clamp to hold the work... and I have saved a quick vice setup from an old chop saw that burnt up in the ranch fire years ago which may be the perfect answer to this idea.....
I will be sure to take allot of pictures for you guys.... but right now nothing is going to happen till it warms up outside 
as my shop is not heated ! 
later all !
Bob.......




.....


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## Superburban

Bob Kelly III said:


> I've been thinking about making a power hacksaw attachment for my lathe.... just to cut through big chunks of steel..... I don't have a chop saw or a metal cutting bandsaw
> just a reciprocating saw.... and I use it all the time... but I was thinking that I could make a power hack saw attachment for the lathe sense my lathe can go extremely slow..... has anyone already done this ?  is it worth the effort ?   but I could make the stroke adjustable and have it clamp to the chip pan and just chuck up the crank in the lathe and turn it on.......
> what do you guys think ?
> ....
> Bob.......


How slow does your lathe go? 12 RPM? I don't think you would want above 20RPM.  I think by the time you make up the bed, clamp, slides, you have the hardest part done. An old motor, switches, wiring, and a couple of pulleys, and you have it all done. 

Ok, I looked it up, and I am off on the speeds. seems like 100 strokes per min are more the norm.





__





						Power Hacksaw Use Info | Diamond Saw Works
					

Our Power Hacksaw information will help you get the most out of our products providing practical advice & solutions to today’s sawing issues.




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That seems awful fast for an arm reaching from your lathe, to a hacksaw table to me.




Bob Kelly III said:


> a friend of mine suggested a small engine crankshaft and rod as the part you chuck up in the lathe ...a bar from the rod to a hinged lever to adjust the stroke of the hack saw....   i thought that was a clever idea ! might cut down on allot of vibration by doing it that way !


A 1&1/2" to 2" stroke, with an arm going to a reciprocating lever to increase the stroke to the 6" to 10 or so inches you would want to use the whole blade, will likely give lots more vibration. Now maybe if you use a long arm, and have it pivot bear the center, so half is going in each direction, may work. 





> .....
> it's obviously gott'a have some sort of table to it that is solidly fixed to the lathe, maybe clamped to the chip pan with short legs. and welded on vice grips !
> .....
> it also needs a clamp to hold the work... and I have saved a quick vice setup from an old chop saw that burnt up in the ranch fire years ago which may be the perfect answer to this idea.....
> I will be sure to take allot of pictures for you guys.... but right now nothing is going to happen till it warms up outside
> as my shop is not heated !
> later all !
> Bob.......





> i have a feeling it would be thrown in a corner and never used ! LOL.....


 Thats what I would hate to see, all the work done, and then used a few times. Maybe try to draw up some ideas, and bounce them off  the brain trust here.


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## Bob Kelly III

I think my lathe with the VFD and all will go down to 1 RPM... i doubt there is much power way down there but that is very very slow .
I doubt I would ever use it faster than 2 strokes a second and that is so slow that I doubt much vibration would be made....
so vibration is the least of my worries at this point.
how to guide the hack saw itself and weight it and provide a spot for it to not saw anything when starting or stopping is a concern ....
I was thinking at first that I'ed just hook one of my hacksaws hanging on the wall to it but the more I think of it that would not be such a good idea
for a few reasons..... depth of cut is one.... strength is another....  so I will more than likely make my own bow for the blade.... and if I do that I just as well go buy some good hefty power hacksaw blades and make it to fit them !
..... I mean if I am going to make something like this ...make it a good one , not something just thrown together .... which I am apt to do on occasion !
LOL.....  something I can cut 1"x6" plate with, or as small as 1" bar stock.
i think looking at power hacksaws would help allot , to see how they are made, why there made that way etc,etc.
and yes it would be just as easy to make it a stand alone unit and not need the lathe at all..... i guess it depends on how much work I want to put into this idea....
hummmm
the main thing is it's gott'a be built from what I have on hand ....I can't afford to run out and buy allot of parts for whatever reason... I mean it took 3 weeks to get a on off on switch that cost only $7.99 ...so buying stuff is almost totally out of the question....
so that reduces it alot... the original idea of something that I could attach to the lathe real fast to cut 1.25" solid steel axle in half is all I really want....
something that I could watch work and not something like the reciprocating saw,...  work it !  
i'll draw it up in Blender and see what I can come up with  !
.......
Bob.......


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## rock_breaker

Several Years ago my SIL used a hand held hacksaw and an electric motor to make a powered hacksaw. The idea was good but the parts he used fit loosely so it didn't work real well. As I recall keeping the saw from flopping side to side was a big challenge.
Have a good day
Ray


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## mmcmdl

I'm surprised no-one has suggested you to buy a $100 HBS . I believe that would be money well spent and you would have better usage for it . ( but I do understand why ) If I can make something for $500 that I could buy for $100 , 90% of the time I make it ..


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## Bob Kelly III

please excuse my ignorance here... your SIL  what is S I L ?
speed is a major factor in something like this....  but yes there will have to be guides or something to keep it from failing around ! 
I remember as a Kid on the Ranch I wanted a saw mill so I had a bow saw blade and a drill and thought why can't I just make a crank from a big nail put it through the hole in the blade and saw wood that way... so I tried it....  and the drill was not variable speed either , the stroke was about 1" in and 1" out........ I hit the trigger on the drill and all heck broke loose !  it wound up spinning like a fan blade at arms length !  it made about 6 strokes on the 2"x4" board and then got air born ! as I backed away from the board it became a prop !  the drill took a long time to wind up and wind down
but that little incident cured me of the recpicating saw mill idea for many years ! ....I did eventually build a bandsaw sawmill that worked fairly well
made quite a bit of lumber with it..... but have sense dismantled it ...... you wouldn't think a 5hp B&S engine would cut a log.... but it did ! I switched to an 8hp B&S and that worked much better on oak ! ....i mounted it on a flat bed trailer..but that flat bed trailer was not flat ! it had a bow in it
so all my wood has this slow curve in it about 2" in 12 feet !  LOL..... oh well it did work for short stuff ! HAHAHAHA
....Bob......


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## Bob Kelly III

mmcmdl said:


> I'm surprised no-one has suggested you to buy a $100 HBS . I believe that would be money well spent and you would have better usage for it . ( but I do understand why ) If I can make something for $500 that I could buy for $100 , 90% of the time I make it ..


HA ! well yah I know what ya Mean !    the harbor freight metal cutting bandsaws haven't been $100 bucks in 20 years  !  i'ed love to have one ! I really would  but they are $250 . now for their smallest one that can only cut 4" stock ! 
problem is I've spent my wad for this year already on the lathe ! LOL I don't think my wife would look too kindly on me coming home with something like that...... I'ed be eating Ramen noodles for a month straight ! 
 ( I used to say I'ed be eating beans for a month but beans are too expensive any more ! LOL)
 living on SSI sure has its downfalls .... I get $589 a month is all, and the wife gets double that.... ( thank God !) early retirement is not the way to go and you can't go back and start the game over either ! 
zigged when I should'a zagged , what can I say ! LOL....
My Step dad used to say " if steam boats were a nickel a dozen I couldn't afford the echo off their whistle ! " HAHAHAHA
later guys !
Bob..........


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## DavidR8

SIL = sister in law 


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## darkzero

DavidR8 said:


> SIL = sister in law
> 
> 
> Sent from my iPhone using Tapatalk


Son in law. Well that is unless rock_breaker's sister in law is so manly that Ray calls her a he.


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## DavidR8

darkzero said:


> Son in law. Well that is unless rock_breaker's sister in law is so manly that Ray calls her a he.



Whoops! Missed that!


Sent from my iPhone using Tapatalk


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## Bob Kelly III

ok thanks for the education <GRIN>  the point was that it flopped around alot..... and that is more than likely because of the speed of the electric motor and or the loose fitting bolts.....
I have seen several home made powered hack saws some very sophisticated in their design but I think a basic hack saw would do the trick
one that sticks in my mind was a length of rod that pivoted somewhere near the motor  and the moving hacksaw followed the rod and weights were added to the rod for faster cutting..... having the ability to raise and lower the saw at will like that has got to be very handy !
the guy also incorporated a kill switch in it to turn off the motor when the blade passed through the metal in the vice and fell about 1/2" to it's doward stop.... problem was that he forgot to make it where it turned off power to the motor completely because when he lifted it it turned it self back on !
HAHAHAH...... he just broke the flow of power with a momentary contact switch..... which worked but gave a strange result !
.....
but a single arm holding the sliding saw would be the way to go I would think....
in this case you could have the pivot of the arm above the crank conection because the rod from the crank needs to pivot on the saw end as well
so as long as you didn't bind it up or something it should move the saw back and forth no matter where it's at !
..... I have an abundance of galvanized 1" water pipe here that I will probably make that arm out of.....
so the pivot arm and the rod follower /stroke adjustment thing that pivots  at the same point .....should take care of the stability issues
of course the saw slide itself will be interesting.... I am thinking 2 pipes one on top the other about 4" apart as the slide rails and simple slightly larger pipe as the slides..... lined with copper as bushings and it should be good to go !,......but I will have to turn the slides down to get that galvanize off them and make them smooth !
.....it should be an interesting build that's for sure ! LOL.....
Bob..........


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## FanMan

Not lathe driven, but is this what you mean?






'twas $10 at a junk shop and come cleaning up and mounting...


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## ThinWoodsman

Ian Bradley mentioned this in one of his books. Basically he fashioned a T-shaped toolholder, where each end of the crossbar of the T had a nut&bolt for clamping a hacksaw blade. The upright of the T goes in the lathe or shaper toolholder. He used portions of hacksaw blades, and had different holders for different lengths of blades. Good use for a broken hacksaw or bandsaw blade.

Check out the fifth post here for an example (not as described, just a thick post with a hacksaw blade clamped in a slot on the end).


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## rock_breaker

Bob Kelly III said:


> please excuse my ignorance here... your SIL  what is S I L ?
> 
> [/QUOTE,,,,,,]Hi Bob,
> "SIL" is what I have been using for Son in Law, If there is a different version I would appreciate hearing about it.
> Have a good day
> Ray


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## Bob Kelly III

Fan man :  Yes.... but the one I saw was bigger and had no gears it was pulley driven throughout.....
.....
but I like the raising arm on it.... get it up and out of the way when clamping down your work  and then bring it back down for the cut....
that's a good design I think !

I drew up a version on Blender I will try to post a pic of it in a bit .....
....
and thanks for the clarification Ray !


Bob.........


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## Bob Kelly III

here's a pic. of the doo-hicky I envision..... 
it's done in Blender..... Bob.


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## Bob Kelly III

in the picture above the dark blue part is what goes into the 3 Jaw chuck for power to the saw....( so your looking at a 3D view)
the white plate is what will become the table, so there would be 2 parts, the saw and the table.
...that's all I have for now !
Bob........


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## Superburban

I like the design. I would suggest a clamp at the front, where the two green bars connect, so you can slide the saw off to replace the bushings, if needed.


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## Bob Kelly III

agreed ! welding that would be stupid ! with no way to get it off !   you will have to replace bushings at some point ! 
and oil holes in the slide tubes as well ....
i like the idea that is is 2 seperate pieces the saw and then the table... which clamps to the lathe.... easier to mess with that way.
.....
should have ball bearings on chuck spindle and the connecting rod on both ends as well as a line of threaded holes on the flywheel for stroke adjustment
 ....at first I was thinking a single crank of say 3" that pushed and pulled a lever and the lever had a arm to the saw....for stroke adjustment....
 but if we do it this way..... it's easier and much less complicated, with fewer moving parts which is always a good thing ! <grin>
.....
Bob....


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## hman

Not a power hacksaw ... but the October issue (and subsequent issues) of Model Engineers' Workshop (www.model-engineer.co.uk, US phone number 866-647-9191) has an article on making a scroll saw/filing attachment for a lathe.  Might have some worthwhile ideas for you.


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## savarin

There is a Gingery Hacksaw book available.
Feb 1964 issue of popular science has an article on building a power hacksaw.
Oct 1953 has a band saw


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## Bob Kelly III

Humm I haven't looked through my gingerly books lately I think I have the shaper , lathe and one other....might be worth looking ! Thanks !
in the video... that is the idea !.....there are 100 ways to do the slides at least, the simpler the better ! but they need to work good and not allow any flopping around !  
I'm just sick and tired of using the reciprocating saw with wore out blades on it to try and cut 1.5" diam. steel  by the time I'm done doing that I am in pain with my Arthritis ! Big time ! and yes I do use cutting oil and go fairly slow but even with a new blade it takes at least 30 minutes ! 
with a dull blade in it .... twice that time.... so a GOOD saw is in order !.... 
......
thanks for the help !
Bob......


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## hman

Bob -
If your major use is to cut steel stock, like 1.5" steel, you might want to consider a bandsaw.  There are lots of threads on the site that talk about the "classic" 4x6 bandsaw. Even the Horrible Freight saw, once set up and a good blade installed, will do a good job on steel rounds.  Another alternative would be a "portaband" type saw.  The disadvantage I see with the corded ones is that they all seem to be obnoxiously *noisy*. So I haven't gone out and bought one.  

What I have been seriously thinking about is the Milwaukee M12 mini-bandsaw.  It has a capacity of 1 ⅝" x 1 ⅝" and is, of course, extremely portable.  Just not sure yet if I'd use it often enough - I have two of the 4x6 bandsaws already.  
Possible sources:








						Milwaukee M12 12V Lithium-Ion Cordless Sub-Compact Band Saw (Tool-Only) 2429-20 - The Home Depot
					

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						Milwaukee M12 12V Lithium-Ion Cordless Sub-Compact Band Saw XC Kit with One 3.0h Battery, Charger and Hard Case 2429-21XC - The Home Depot
					

The Milwaukee M12 Sub-Compact Band Saw Kit is the most compact and lightest weight cordless band saw on the market. The M12 Band Saw provides one-handed power and portability to electricians, maintenance



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						Milwaukee 2429-21XC M12 Cordless Sub-Compact Bandsaw Kit - Power Band Saws - Amazon.com
					

Milwaukee 2429-21XC M12 Cordless Sub-Compact Bandsaw Kit - Power Band Saws - Amazon.com



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						Milwaukee 2429-20 Cordless Sub Compact Band Saw: Power Band Saws: Amazon.com: Industrial & Scientific
					

Milwaukee 2429-20 Cordless Sub Compact Band Saw: Power Band Saws: Amazon.com: Industrial & Scientific



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Note that 2429-20 is just the saw itself (with blade).  The 2429-21XC kit includes a battery and charger.


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## Bob Kelly III

A friend of mine got the Bauer portable band saw from Harbor freight when it was on sale for $99.00
and he made a steel table and stand to hold it and it has served him well for small projects....
the 4x6 H.F. Bandsaw is more to my liking and I could fix it to where it would work good for me but it's gone up to over $250 bucks now 
and after spending my Years worth of money and then some on the lathe I can't get one now ... it'll be a year till I can afford something like that !
but when I do I can dismantle the lathe hack saw and use it for something else ! LOL......
....but in all truthfulness....I'ed rather make it if I can.....  all I would have to do is get a metal blade for my home made bandsaw and slow the thing down with a jack shaft and I would be good to go ....but it all takes money ...
so right now I just find the design I like the best ...then make it when I can !
....
later !
Bob...........


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## yendor

Take a look at this OLD Popular Science Project.
It uses (2) Piston Connecting Rods.


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## Bob Kelly III

very interesting ! did you notice that the direction of the pushing out connecting rod was also pushing down on the saw into the work ?
some home made ones are pushing up and that is no good for cutting  !
thank you !
Bob.........


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## Superburban

Bob Kelly III said:


> some home made ones are pushing up and that is no good for cutting  !
> thank you !
> Bob.........


What if they are having it cut on the return stroke? Just thinking out loud here, but slight lifting on the push, and pulling down on the pulling and cutting stroke may be a decent design feature.


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## Bob Kelly III

well, yah depends on what your building it could work both ways.... but I've seen videos of home made saws that  1.) were going too fast
and 2 .) hit the blade with such force Upward as to make the blade hop up....
i think just by turning the blade around it would make that saw really cut very fast....
you need to observe the motion and ascertain what the mechanics are doing to the blade for the best cutting action
....   but obviously just about anything will work....LOL
some designs are super simple.... no slides needed at all, just a pivot in the back.....  and that is quite innovative !
I think I will Draw up another version in Blender using that method... as it really is quite simple.... no bearings needed !
..... just good tight pivots ....
Bob.....


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## Bob Kelly III

well today I got the holding vice done for the hack saw attachment for the lathe....
I was going to restore the quick vice that was on the chopsaw base but it was just too far gone to bother with  so I made up a new 5/8" threaded rod portion and used a long coupling nut and welded it to a bracket I made..... put the turn handle in it and assembled it ...it works great  !
it will hold anything I wann'a cut without moving around !  it can also rotate to 45 degrees .... so that will be handy.
...... next is the base for the vice base and then the hacksaw and crank for the chuck on the lathe  not to mention the back pivot arm...
which needs to be very carefully done so as not to allow any sideways movement in it's 2 pivot points.....
then I gott'a figure out how I'm going to attach it to the lathe so it's fast and easy to put on and off .
I think I'll make the stroke of the crank  4" max with a minimum stroke of 2" and a spot between them at 3".... movement of the saw itself will be double that measurement.... so the minimum stroke for the saw will be 4" and Max stroke of 8"  ....so 4, 6, & 8, inch strokes..... I have no idea if that is good or bad..... i guess it is try it and see  LOL.....
.....
Bob.....


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## DavidR8

Bob Kelly III said:


> Humm I haven't looked through my gingerly books lately I think I have the shaper , lathe and one other....might be worth looking ! Thanks !
> in the video... that is the idea !.....there are 100 ways to do the slides at least, the simpler the better ! but they need to work good and not allow any flopping around !
> I'm just sick and tired of using the reciprocating saw with wore out blades on it to try and cut 1.5" diam. steel by the time I'm done doing that I am in pain with my Arthritis ! Big time ! and yes I do use cutting oil and go fairly slow but even with a new blade it takes at least 30 minutes !
> with a dull blade in it .... twice that time.... so a GOOD saw is in order !....
> ......
> thanks for the help !
> Bob......



Have you tried the Diablo metal blades? 
I was skeptical till I tried them. 
I cut some 1” square hot rolled stock in under 5 minutes. Many cuts with the same blade and I didn’t notice any decrease in cutting ability. 

Seems a lot of work when a few blades might save you a bunch of head scratching and fabrication. 


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## Bob Kelly III

Hi David !
well, no I have not tried anything but the cheapest metal blades as to me they are way too expensive as it is !  LOL....
I usually get the 10 pack  and get them as long as I can afford.... and I try to  use the entire blade not just by the hilt of the Reciprocating saw.
but they go away fairly fast some better than others...but they are disposable blades.
.....
 I was really impressed at seeing the metal cutting chop saws with actual saw blades in them  and how well they cut steel !
but those puppies are expensive as heck ! i can't justify one of those... now perhaps if I made one....... hehehehehe
.....
I got the vice base bolted down to the aluminum plate this morning... but didn't get any further than that today.
.....
i put the unit on the lathe and am confronted with clearance issues...that I didn't expect so I gott'a work that out.
started to work on the back pivot arm but got derailed on something else....
....
I did gather up the material for the saw frame itself, but that is as far as I got today.
.....
later !
Bob......


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## DavidR8

I recommend trying the Diablo blades as you might be pleasantly surprised. 


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## Bob Kelly III

I just might do that ! thanks ! 
Bob.......


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## Bob Kelly III

I got alot accomplished today before the cold made it hard for me to move around.... I got 2 brackets welded up and the plate extension bolted on
and right now it is setting on the lathe under the chuck held on with a pair of vice grips ...   that 1/4" aluminum plate is way to flexible  ( obviously)
so I am going to have to add some table supports. but I am almost ready to attach the back pivot and whip up the saw arm and attach it too.
the crank I also welded up today so I had some sort of reference point  at which to attach the back pivot to.... 
...so it's getting closer to picture taking time !  lol.....
.... i was thinking about mounting the aluminum plate and vice  onto a 2"x 12" plank for rigidity .... and a softer contact point on the ways of the lathe !
.... i just might do that !  take and route a groove for the V's on the ways so it aligns the same way each time.... and then clamp it down.
.....
Bob.........


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