# Newbie question - cutting bar stock



## mooseman (Sep 21, 2008)

Apologies if this is mentioned elsewhere on the forum, and I really hope this isn't too basic, but.....

What would be the most effective way to cut bar stock to size.....I'm kind of suspecting the answer will be "a hacksaw and liberal elbow grease", but is there a more effective way? What I want to do at the moment is cut a 2 inch chunk off a 10 inch piece of 2" diameter round aluminium.


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## CrewCab (Sep 21, 2008)

MM .............. think you have answered your own question 


Basically, imho, it depends on how much money you want to throw at the problem ...............  

Cheapest way, .......... Hacksaw, with a decent blade it shouldn't be too bad really, even at my age  ........ I would tackle that easily enough, if it were steel mind, I'd sub-let it to some of the younger guys 8)

Options 2/3 .............  Power Hacksaw / Bandsaw ............. more expensive, but much easier on the biceps  ........... my preferred weapon is the "Power Hacksaw"

CC


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## ksouers (Sep 21, 2008)

If you have a lathe, you could chuck it up and spin it and use the hacksaw on it. That's the way to part off in the old days. Just be extremely careful. Don't get the saw anywhere near the chuck.


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## rake60 (Sep 21, 2008)

I would suggest shopping around for a 4 X 6 bandsaw as your hobby
budget allows.

The import version of that saw sold by Harbor Freight looks like this:
*Harbor Freight Bandsaw*

My own looks a little different than that.




It's the SAME machine painted grey to accept a Clarke name plate. 

I've seen them on sale for little as $159 USD

Rick


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## CrewCab (Sep 21, 2008)

2" stock really needs a 5" chuck though, ........... at least my 4" chuck won't quite accept 2" stock, so a small lathe could struggle :

Sorry MM ................ you could be back to the hacksaw :

CC


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## malcolmt (Sep 21, 2008)

Hi Moose
My thoughts are a) a coarse blade in a hacksaw, 10min's little effort.
b) a medium /fine woodcutting blade in a diy jigsaw, ali clamped in the vice, hold the jigsaw firmly in both hands One around the front of the saw One on the handle/trigger, let the saw do the work (i.e. don't force it) 2Mins very little effort.

Kind regards

malcolm


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## CrewCab (Sep 21, 2008)

malcolmt  said:
			
		

> jigsaw



Bloomin' good suggestion Malcolm 8)

CC


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## malcolmt (Sep 21, 2008)

Why thank you sir 

Malcolm


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## Bogstandard (Sep 21, 2008)

Odilon,

It also depends how much room you have.

For over 20 years, when I cut any non ferrous material, I use an old B&D vertical hobby bandsaw. I have cut up to 5" diameter ali on it, takes time but it does it, using the finest toothed blade you can get. I have seen them as low as £70 for a 2 wheeled one. Another couple of good points are that they can be used for cutting wood (ply sheets etc), and also they are compact enough to sit on your bench, or hide from the better half.

If your are going to cut any ferrous materials, you are back with what the other lads have told you about, but they do take up rather a large amount of space. 

John


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## mooseman (Sep 21, 2008)

Thanks for all the good advice gents!

BTW, I made a silly mistake in my post - where I wrote 2" diameter I meant 20mm diameter.

Looks like I might save up for a bandsaw then, but in the meantime I'll stick with my trusty hacksaw, and I'll see what can be done with my jigsaw as well.


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## CrewCab (Sep 21, 2008)

mooseman  said:
			
		

> where I wrote 2" diameter I meant 20mm diameter.



Nail file then ;D

CC


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## Kludge (Sep 21, 2008)

*furiously scribbling notes and noting I'm running out of envelope backs.* ;D

Keep going, folks. I'm getting quite an education/refresher here. 

BEst regards,

Kludge ... blaming it all on the meds.


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## HS93 (Sep 21, 2008)

I recently had to cut seven blocks of 75mm X 25MM and seven 7mm X 40mm all ally
just use plenty of WD40 and a good blade ,oh and a good fixed vice, and don't try and do them all at once, start each setion with some cutting.one of the finished blocks

Peter


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## wareagle (Sep 21, 2008)

For aluminum, you can use a carbide tipped blade in a circular saw. That will make short work of your task! 

But beware, this isn't a good idea for steel, stainless steel or other materials that are harder than aluminum. And if you are using a typical home owner's grade circular saw, don't do this too many times as the motor will heat up to the point of destroying the windings. For a couple of cuts, you'll be fine. And, use the typical precautions needed for using a circular saw!! Safety glasses, beware of blade binding, etc.


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## steamer (Sep 21, 2008)

If you get the ubiquitous 4x6 bandsaw, throw the stand that comes with it away, its useless.

Make a roll around cart for it.  Set the bed about a foot off the floor.  Now you can bring long stuff outside to cut. Additionally, if it is low enough, it can go under the lathe or bench when not in use.
Mine is constucted of 2x4s and 3/4 ply with glue and screws. Its on casters, Its rugged and portable.

PS I make no appolgies for the mess.....It gets used a lot! ;D

http://i164.photobucket.com/albums/u27/mcandrew1894/P9210077.jpg


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## Stan (Sep 21, 2008)

mooseman: You don't say what equipment you have other than a hacksaw. If you have a small lathe, the standard method would be to put one end in the lathe chuck and the other end in the steady rest with a bit more than 2" sticking out and then cut off with a parting tool. If you have a lathe with a spindle ID greater than 20 mm then feed the bar through the headstock and cut off what you need with the parting tool.

crewcab: A 4 inch chuck should easily hold 5 inches with the outside jaws or on a four jaw, by reversing the jaws.


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## mooseman (Sep 22, 2008)

Thanks all,

Stan, I have a modified Unimat 4, but I've only had it for a few days.As I am totally new to all this, all I've done so far is familiarising myself with all the components and with basic methodology - not done any actual cutting yet!

Other tools in my small arsenal include a power fretsaw, power jigsaw, a dremel and quite a decent drill that has been used in the past for small turning jobs.


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## DickDastardly40 (Sep 22, 2008)

I don't know what the diameter through the spindle is on a Unimat 4 is and parting a piece off would only be possible if your barstock will fit through the spindle and you can part close to the chuck.

If you have a bench vise or a workmate you'll be able to grip and whizz through 20mm dia ali with a hacksaw (not a junior) as quick as anything; possible even quicker than findng and putting the correct blade in your jigsaw. Getting the cut straight is a whole other skill.

With cutting anything, having it securely held still is key so that any effort is expended into the cut and also helps with the straightness of the cut.

Have the line to be cut as close to the vice jaw or edge of bench if you are securing it by g clamps to prevent the barstock from flexing.

Hope this is of some help

Al


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## CrewCab (Sep 22, 2008)

Stan  said:
			
		

> crewcab: A 4 inch chuck should easily hold 5 inches with the outside jaws or on a four jaw, by reversing the jaws.



 ??? ............. Oooops ..... a Senior Moment : ............... Cheers Stan


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## Bluechip (Sep 22, 2008)

Hi Troops ...

I use a Sabre Saw, or Reciprocating Saw, as they are called.

Cut off a 2 dia. in. chunk of EN25 a few months ago, took about 3 minutes with Rocol RTD. lube.

About 50 GBP or so for a Draper, mine's a Bosch, had it for years, cuts aluminium with a coarser pitch blade.

Handy tool, avoid cheaper blades like the plague, Bosch or Makita seem to last for ever.

Just a thought.

Dave ..


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## Circlip (Sep 22, 2008)

I remember watching a model making programme (UK version of program) and a guy who made Dolls houses found himself twiddling his thumbs while waiting for his electric screwdriver to recharge, forgot he had the handraulic version,-seriously.
 OK mooseman, how many thousands are you cutting off? Way I do it including 2" barstock is to get a strip of paper and wrap it around the bar keeping the edge of the paper square with line I want to cut to. Grip in vise or chuck and start with a handraulic hacksaw, keeping it vertical- you can see this with the line of the edge of the paper. Only go a FEW mm or fractions of an inch deep (delete as necessary) and rotate the job a few degrees and carry on cutting and repeat the steps. Squish cutting fluid on as required. You'll be surprised how quickly and square you can cut bits by this method, It's all very green as well. :big:

 Regards Ian.


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## Stan (Sep 22, 2008)

Now we are much better informed. There is a big difference in a Unimat and even the little 6" (3" British) Atlas. You will not be doing much work with 2" round bar except the occasional disc for a flywheel. 20 mm round bar (aluminum or steel) is an easy hacksaw job. Starting out in the model building hobby there are many tools you will need before you need any kind of power equipment to cut 2".

Stick around this site, ask questions and glean ideas and have a world of fun/


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## firebird (Sep 22, 2008)

Hi

I made this power hacksaw for next to nothing when I first got started in metalwork. It is powered by a 12 volt windscreen wiper motor. Not the fastest thing in the world but a lot easier than cutting by hand. It served me well for quite a while.












Cheers 

Rich


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## steamer (Sep 22, 2008)

Hi firebird,

Didn't MEW do a build on a 12V powered hacksaw recently?

Dave


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## mooseman (Sep 23, 2008)

Thanks for all the great tips gents!


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## firebird (Sep 23, 2008)

Hi Dave,

Yes they did, this is the one. After I had finished building it I wrote it up into an article and drew plans. If anyone is interested I can dig out the plans and upload them.

cheers

Rich


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## CrewCab (Sep 23, 2008)

firebird  said:
			
		

> If anyone is interested I can dig out the plans and upload them.



As if you need to ask  ...... Yes Please Rich ........... btw, what do you use as the 12 volt power plant 

CC


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## firebird (Sep 23, 2008)

Hi CC

In the workshop I used a 12 volt battery charger but any 12 volt supply, car battery/transformer will run it.

Cheers

Rich


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## mooseman (Sep 23, 2008)

Yes please Rich, I'd love to see those plans!


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## CrewCab (Sep 23, 2008)

Thanks Rich, I've got a small 12volt psu which is really useful but it only pushes out 1.5a, anyway no doubt I can sort it out once I've sourced a suitable wiper motor, anyway if a battery charger is big enough then it's no real problem. 

That looks a really useful little tool, I've got a big one that sits under the bench but I think a small one to use standard hacksaw blades and use on the bench top will get used a lot 8)

I've a feeling these plans will prove to be a popular download 

Cheers 

Dave


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## Twinsquirrel (Sep 23, 2008)

mooseman  said:
			
		

> Yes please Rich, I'd love to see those plans!



Me too!!!


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## firebird (Sep 23, 2008)

Hi

Heres the plans. I had to scan the drawings and then upload so I hope they are clear enough.































Cheers

Rich


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## itowbig (Sep 23, 2008)

yaba daba do ive got a band saw but its nice to add more to the box.
thank you 
there is so much here on this site to keep you busy forever
(and yes im going to live that long)


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## BobWarfield (Sep 23, 2008)

I started with a 4x6 bandsaw bought for $40 used. It worked great, but it was slow even though I bought a nice Starrett Bimetal blade for it. I had a chance to use a big one at the Community College and it was better, but still slow. Then I came across something called a DeWalt Multicutter:






This thing rocks. Cuts faster than an abrasive chop saw, cuts mild steel and non-ferrous metals just fine. You see it chopping up a big hunk o' 6061 in that piccy. It is a carbide blade on a special saw that runs it more slowly so it lives longer. I use it constantly on all sorts of things. If I was a welder, I would think one would be indispensible. It is basically a poor man's cold saw. Cost to me was $400, although they list for a lot more. Shop carefully and you can find a deal. Perhaps an enterprising HSM could remotor or modify an existing chop saw to run more slowly and just use a carbide blade on that too.

Rarely, I have wished for an abrasive chop saw to cut hardened steel. For example, to trim a ballscrew for a recent CNC project. Those are pretty cheap, so I'll probably eventually succumb.

The bandsaw sat unused for nearly 2 years after I got the Multicutter. I dragged it out once to cut a 5" cast iron blank for a faceplate. That 5" is too much for the Multicutter.

And then I realized I could really use a vertical metal cutting bandsaw. So I drug it out again, ditched the stand as Steamer wisely recommended, and made a table for it:






The rolling cart is much sturdier and put the table at a comfortable height. I use the shelves and drawers for offcuts, and keep my hacksaw and blades in the top drawer. Now the little bandsaw is used more than ever to do fine trimming on things.

Cheers,

BW


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## wareagle (Sep 23, 2008)

Here is another chop saw suitable for cutting off stock. It is basically the same as the saw Bob has shown, but are a little less expensive. The saws are great and last a suprisingly long time. Here is the link: *Evolution Saw**

Mooseman, have you succeeded in your endevour?*


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## BobWarfield (Sep 23, 2008)

Wareagle, I've heard good things on other boards about those Evolution Rage saws.

Best,

BW


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## bigsteve (Sep 24, 2008)

Not that it will likely be cheaper than what you could find at your local junk yard, but if you need a windshield wiper motor for your power hacksaw, you can get one for $19.95 + S/H (in the US anyway) from Burden Surplus:

http://www.surpluscenter.com/item.asp?UID=2008092406350029&item=5-1664&catname=electric


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## firebird (Sep 24, 2008)

Hi

Iv'e just come across the text for the original article as it was published. I can cut copy and paste if anyone wants it.

Cheers

Rich


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## CrewCab (Sep 24, 2008)

Rich ............... no need to ask mate ........... 8)

Just "Cut n' Paste awayplease ;D


CC


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## firebird (Sep 24, 2008)

Hi

Well heres the text.



Dear Sir,
        As every model engineer knows its often necessary to cut off a lump of metal, steel or brass etc, to a size that will fit in one of the machines. To me a hobby is something you do for pleasure, coming home after a hard day at work and standing at the bench vice hack sawing through inch thick steel bars is not a pleasure. One option is to take the bar to work and let Ben, the lad, cut it for me but this isnt always convenient, (and makes Ben curse a lot) because I usually need the bit at night or the weekend. What I needed was to keep Ben under the bench and bring him out when needed or get a machine to do it for me. Of course there are metal cutting saws on the market and much as I would love to pick up one of the many mail order catalogues and order one of everything a shortage in the cash department prevents this. So it was that I put my mind to solving the problem of how to make one. Most metalworkers Im sure have made there own tools of some sort, jigs and clamps etc. but this project would make the leap from making a hand tool to making a power tool. I quickly discounted the idea of a band saw, it would be far to complicated, and so decided that a powered hack saw was the answer. Over the next few weeks many scribblings and jottings started to clutter the bench but I still had the problem of what to power it with. The answer came to me one day at work; Im in the motor trade, while working on a car. The wipers were gracefully sweeping to and fro when it hit me. As I watched the movement everything seemed to fall into place. 12 volt. Why not. Much safer than playing about with mains powered motors and anyway many cordless power tools nowadays run on low voltage. Now Im not suggesting you should rush out and grab hold of the wipers on the old Mondeo but take it from me they are quite powerful. The motors work on a worm and gear arrangement and are very reliable, we very rarely have to fit new ones, and if you think about it they are capable of running for long periods of time. They very conveniently rotate at about the right speed, (Imagine cutting a piece of metal by hand while keeping in time with the wipers on your car) come fitted with a crank and have all the necessary links and bits and pieces etc that you will need. As I mentioned earlier Im in the motor trade so quickly had the parts stripped out of cars that were being scrapped. The photos show the complete mechanism from a 1993 Ford Escort and a Vauxhall Astra of about the same vintage, (this is how the mechanism comes out of the car, as a complete unit) also shown is the crank from a Rover 214. You will notice that although there are differences they all work on pretty much the same principle. I chose to use the one from the Ford Escort purely because it has the greater crank sweep of the three at 106mm which will give a saw stroke of the same amount compared to the Vauxhall at 78mm and the Rover at 80mm, although it wouldnt be to difficult to extend the crank by cutting in half and welding/riveting/ bolting a longer piece in. I havent investigated other makes and models of car wiper motors in depth but apart from the crank sweep as mentioned before they are all pretty much the same. The Escort and Astra units are fairly easy to remove, all done from under the bonnet. Other makes and models can be more difficult. If you dont know of anybody scrapping a car where you can get the bits for free and have to go to a car breakers you shouldnt have to pay much more than a tenner. One other thing, get the plug by chopping 6-8 inches or so off the end of the wiring loom, its not absolutely necessary but will make the wiring up easier and neater. Back home in the workshop a couple of quick experiments on power supplies was carried out. It will of course run off a car battery, it will also run quite happily off a 6-amp battery charger or a transformer. Having satisfied myself that the motor would power the saw it was time to empty out the boxes full of bits that will come in handy one day. At this point I think I ought to emphasise that although I wanted a power saw this project was purely experimental so I make no excuses for mixing imperial and metric and using whatever came to hand. As far as possible I will give measurements in mm. Hindsight being a wonderful thing, if I was making it again I would do things differently, but on the basis if it works leave it alone I probably wont. Wherever I can I will throw in suggestions of alternative methods or ideas and afterthoughts. I suggest therefore that you take a good look at the finished tool and use the measurements and drawings as a guide and adapt them accordingly. Its highly unlikely that there are two of us with the same box full of bits and pieces. As I have already said this was an experimental piece so engineering excellence it isnt but that said care was taken to keep things as square as possible where it mattered. Although I have used the lathe and milling machine on some parts this is not necessary and the whole thing could be made with basic tools, a pillar drill being advantageous. So let us begin. The idea I came up with is to have a saw frame slide to and fro on an arm that is pivoted at one end. The arm pivots up to take differing thicknesses of work and keeps pressure on the work via its own weight. The motor mounts directly on to the arm and drives the saw via one link thus doing away with the need for any complicated mechanisms. (Keeping things as simple as possible is always the best policy when carrying out experimental work I have always found.) A piece of steel channel will form the base onto which will be bolted a vertical post to mount the swinging arm to. A simple vice will be needed to hold the work. On the electrical side I will need an on\off switch and a switch that will cut the power as the saw reaches the end of the cut. With a few rough sketches and measurements I set about making it. Much of the flat steel and the box section steel I bought from B & Q. They have a good selection of brass, steel and alloy in a variety of flat, angle, round, square, tube and box sections. I started with the saw frame. This I decided should have a 140mm depth of cut so as to be able to accommodate larger tube sections as well as smaller solid parts. The frame is designed to take 10 inch blades purely because I had 20 or so in stock. Although not as common as the 12 inch blade they are still available. The saw has a stroke of 106mm and therefore will not use the entire blade anyway. It will of course keep the finished machine 2 inches shorter and the shorter frame will be more rigid. I can see no major problems with using 12 inch blades just remember to make the frame and the swinging arm 2 inches longer. I started with the saw frame. Cut a piece of 35mm x 20mm x 1.5mm oblong steel box section to 305mm in length and 4 pieces of 30mm x 4mm flat steel to 180mm in length. Clamp the flat steels together in pairs. Drill a 5mm hole through each pair to take the spacer and countersink the holes then cut\file\mill the 4mm slots that take the blade mounting blocks. One arm from the wiper mechanism must be removed. File or grind off the part of the wiper spindle that has been riveted over and lever off the arm. A square hole must now be cut in the side of the oblong steel section just big enough for the arm to slip in. (The position of this hole must be worked out. The type of motor used, crank sweep, the length of the connecting rod etc. will all have an effect on its position). Clamp the arm in place and drill 2 x 2mm holes through the box section and arm. Remove the arm and drill the 2 holes out to 5mm and tap 6mm. Drill out the two holes in the box section to 6mm. Make up two spacers to 20mm, (the same width as the oblong box section) I made mine on the lathe from 12mm hex steel bar, drilled and tapped 5mm that will take a 5mm x 12mm countersunk machine screw from each side. You could use a piece of tube as a spacer with a nut and bolt right through. Fit the spacers to the flat steels and then clamp to the oblong box section with mole grips and check with a square. To speed the job up a little I took the frame to work and welded the parts together. If possible do the same as welding makes a good solid frame. (Speak nicely to the guy at your local car welders)Alternatively use bolts\screws\rivets to fix the frame together. Using triangular plates at the corners will considerably strengthen the joint. Cut two 30mm lengths of the oblong box section to form the lower guides. Slide the frame onto a length of the box section; (that will become the swinging arm) slip the two short guides of box section into the frame and push them up to the top trapping the swinging arm in place. Secure the two guides with mole grips or clamps and check that the frame slides freely along the arm with the minimal amount of free play, adjust as necessary. Drill eight 1\8 inch holes through the sides of the frame and secure the short pieces in place with 1\8 pop rivets. Cut two blocks of steel 35mm x 20mm x 12mm to make the blade mountings. Cut out or mill off one corner. On one piece drill and tap 4mm for the blade mounting screw and drill through 4mm to take a 32mm length of 4mm rod. Very lightly peen the rod in its centre and press into the block so that it is central. On the other block drill and tap the same for mounting of the blade. Next drill 5mm to a depth of 10mm and tap 6mm to take the adjusting stud. Screw in a 25mm long bolt then drill through to take the 4mm bar, this will go through adjusting stud and hold it securely in place, lightly peen the rod and press through. Note that the 4mm rod is in a different position on each blade mounting block. Cut the head off the bolt, clean up the thread and fit a large washer and wing nut. When the blocks are fitted in their respective slots in the frame they are held rigidly and will not allow the blade to twist. The swinging arm is a 545mm length of the oblong box section. Drill through one end to take a 24mm length of 12mm tube with a 10mm bore. I brazed the tube in place but soft solder would do just as well. Cut a 120mm length of 14mm x 5mm steel and a 70mm length of 14mm x 5mm steel. These two pieces will make up the bracket for attaching the spring counter balance. Clamp the shorter piece to one end of the longer piece and drill through the two pieces with a 2mm drill at 50mm centres. Clamp the long piece to the bottom of the swinging arm and drill through with the 2mm drill. Drill out the holes in the long piece and the swinging arm to 6mm and drill the out the holes in the short piece to 5mm and tap 6mm. Drill a 4 mm hole in the other end of the long piece to which the spring will be attached. With the short piece pushed inside the swinging arm the long piece can now be bolted on from the outside with two 15mm long 6mm bolts. The motor mounts onto the swinging arm via a 3.2mm thick 130mm x 80mm steel plate. Cut an 80mm length of 25mm x 6mm steel and clamp to the bottom of the motor mounting plate. Drill two 2mm holes at 40mm centres through both pieces. Clamp the motor mounting plate to the swinging arm and drill through the two 2mm holes. The motor mounting plate and the swinging arm can now be drilled out to 6mm. Countersink the motor mounting plate. Drill out the piece of 80mm x 25mm steel to 5mm and tap out to 6mm. A 25mm hole must be made in the plate for the motor spindle to go through by drilling and filing. Three further holes must be drilled for the motor mountings. (The position of these to be taken from the motor you are using). By slipping the drilled and tapped plate inside the swinging arm the motor mounting plate can be fitted with two 6mm countersunk machine screws. Its a bit fiddly lining up the holes but once bolted up its nice and solid. Thats about it for the frame and swinging arm but its worth having a test run now to check that all runs sweetly. Fit the motor to its mounting plate. Clamp the swinging arm in a vice and slip on the saw frame using a little light oil (3 in 1). Press on the connecting rod. Connect the motor earth lead to the 12 volt power supply earth and touch the other wire onto the positive power supply. Its fairly safe doing this as we are only playing with 12 volts but be aware that it can kick out a decent spark. If alls well then the frame should move back and forth with no strain. I have to admit its very satisfying to see it move for the first time. If alls well then we can move onto making the base. The base is a piece of channel 45mm high x 95mm wide x 3.3mm thick x 525mm long. It already contained a few holes but these have no effect at all. The swinging arm of the saw is mounted on a vertical post bolted to the side of the channel. The post is made out of a piece of 185mm x 50mm x 8mm steel. Drill two 2mm holes at one end and clamp the post to the channel, use a square to make sure the post is true and vertical. Drill through the two holes with a 2mm drill then open out the holes in the post and the channel to 8mm. Cut a piece of 30mm x 4mm steel to 120mm in length and drill two 8 mm holes in one end to match the holes in the post. Drill a 4mm hole in the other end.


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## firebird (Sep 24, 2008)

Hi

It was too much to upload in one go (exceded 2000 characters) so heres the rest.

This bolts on with the post to form the counter balance spring lower mounting. The pivot for the swinging arm I turned from a piece of brass hex but a nut and bolt with a shank would do. Drill a 10mm hole at the top of the post to accommodate the pivot. The position of the pivot is such that the swinging arm is parallel to the channel at the bottom of its cut. Drill a hole for the on off switch and two 5mm holes tapped out 6mm for mounting the micro switch bracket. The micro switch bracket is made from a strip of steel 135mm X 25mm x 2mm, sturdy enough to hold the switch but thin enough to be bent into place when setting the switch. When the saw finishes cutting through the work piece it will drop slightly before switching off the power then come to rest on a stop. The stop will in fact have three functions. Firstly a stop, obviously, secondly it can be used as a depth of cut limiter and thirdly as a prop to keep the saw out of the way while setting up the work piece in the vice. Cut a piece of 30mm x 4mm to 145mm in length to make the stop mounting post. Drill two 2mm holes at one end and clamp in position on the channel checking with a square. Drill through the channel with the 2mm drill then open out the holes in the channel and the post to 6mm. Drill a 1\4 inch hole at the top. Cut a block of steel x25mm x x25mm x x22mm and drill through to 5mm and tap out 1\4 inch whitworth. (The thumb screw I found is 1\4 whit) Cross drill the block to 6mm. A 6mm length of steel bar bent over at one end forms the adjustable stop. Bolt the stop post to the channel with two 6mm nuts and bolts. The block is bolted to the top of the post with a 1\2 inch long 1\4 whit bolt, the 6mm steel bar drops through the hole and is held in position with the thumb screw. The bar length is designed so that when it is allowed to drop to the bottom it is in the correct position for the saw to rest when the power is cut. Last but not least we will need a vice to securely hold the work piece during the cutting operation. The two vice jaws are made out 40mm x 40mm x 6mm angle iron cut to 95mm in length. Now you would think that angle iron would be 90 degrees wouldnt you but the bit I was using wasnt as is clearly demonstrated in the photos. Although this is going to be a fairly crude vice it will work a lot better if the jaws close together reasonably well. To get over this I clamped the two jaws back to back in the milling machine vice and took light cuts until the two faces were reasonably flat. The same could be achieved in the bench vice with a flat file and a square. The fixed jaw of the vice simply bolts onto the channel with two 10mm bolts, making sure it is as square as possible. Two brackets 26mm high x 22mm x 25 wide with 10mm holes in are bolted on using the same jaw mounting bolts. (These brackets were an after thought; there use will be demonstrated later). I wrestled for some time about how to make the movable jaw and eventually settled on the method here. After all this does not need to be a precision machine vice but simply good enough to hold the work secure and reasonably square while the saw does its work. Two slots need to be cut in the channel 8mm wide x 110mm long with centres 53mm apart. I did this by drilling a series of holes using the bench pillar drill to remove much of the waste and then milling out on the milling machine. Alternatively use flat and round files to complete the slots. The movable jaw now has two 6.8mm holes drilled at the same centres as the slots and then tapped out to 8mm. Acquire or make two 8mm studs to the dimensions shown. Cut a piece of 40mm x 10mm x 85mm steel and drill two 8mm holes on the same centres as the stud holes and slots. This piece fits inside the channel and helps to guide the movable jaw. A 300mm length of 12mm threaded rod is used for the vice screw. The screw block is made from a piece of 25mm x 25mm x 65mm long. Drill and tap 12mm to take the vice screw and then drill the two 8mm mounting holes. Clamp the screw block in place on the channel checking for square and drill through with the 8 mm drill. A 1.5mm thick x 32mm x 45mm `U` Shaped piece of brass with a 6mm thick x 45mm x 10mm aluminium spacer is fixed to the rear vertical face of the movable jaw with two 6mm bolts screwed into threads tapped into the vertical face. Two small brass studs are also fixed to the vertical face of the movable jaw with 6mm countersunk machine screws (their use will be demonstrated later). File off any protruding threads to leave the vice jaw smooth. The end of the vice screw is fitted with a turned and internally threaded brass boss with a groove in it held in place with 1\8 inch steel roll pin. The movable vice jaw is simply pushed forward by the brass boss pushing on the rear vertical face of the jaw and pulled back by the action of the groove in the boss which is located in the `U` shaped slot in the brass plate. An alternative to a turned brass boss could be to fit two nuts with a 1.5mm space between them and then drill and pin the nuts in place, file the nuts round and make the slot in the `U` shaped piece of brass to suit. Once all the parts are fitted to the movable jaw all protruding screw threads and heads must be filed flush. I found a hand wheel in the scrap box that I used on the vice screw held in place with a grub screw. As an alternative cross drill the end of the screw and fit a short length of bar. The vice does not need to exert any great pressure, just enough to hold the work piece. Two lengths of 1\2 inch x 1\2 inch aluminium angle are pop riveted to the sides of the channel to allow the saw to be fixed on to a 140mm x 30mm x 535mm piece of wood, this makes it easy to clamp to the bench or fit into a workmate type bench. I think that just about covers everything on the mechanical side. Steel has a nasty habit of corroding so with the dregs of a few tins of hamerite I painted it up a little. Dont paint where the saw slides on its swinging arm or where the movable vice jaw runs though. Connecting the power supply to the saw is via two brass rods mounted on a hard wood base. The hardwood insulates the power from the metal of the machine. To make the power supply connector first cut a piece of hardwood to 120mm X 30mm X 15mm thick. Cut two pieces of 3.2 mm thick brass 38mm X 25mm. Drill a 6mm hole dead centre of each piece and then drill and countersink two screw holes in each piece. The brass rods I made in the lathe by cutting off a 50mm length of 9/16 diameter and turning the first 10mm down to 6mm and threading with a 6mm die. Alternatively drill into the end with a 5mm drill and then tap out to 6mm. Mount the rods on their respective brass plates with a 6mm nut or bolt. Mark out the hardwood block and recess where the nuts will be with a 12mm drill to a depth of 10mm. Drill two 6mm holes for mounting the block on the saw frame. Hold the brass plates on the hardwood block and mark the screw holes. If you use brass screws like I did its best to pre drill the screw holes with a 2mm drill to avoid the screws snapping off. Hold the hardwood block on the saw base and mark through the mounting holes. Drill out to 5mm and tap out to 6mm. Although the base is only 3.3mm thick it will take enough thread to hold the block securely enough. Screw the hardwood block to the base with a couple of pan head machine screws. Screw the brass plates and rods onto the hardwood block with one brass screw in each. Anything with crocodile clips, e.g. the battery charger, jump leads off a battery or even an adapter made up that plugs into the car cigarette lighter socket can now be quickly connected to the machine. The electrical side of things is dead easy. All you need is to find the two wires on the motor that give the fastest speed. One will be common earth; the others will be for the different speeds. Cut the unwanted wires out of the plug. Use crimp type electrical connectors throughout to make good connections. Take one wire from the motor to the brass rod and connect with a brass screw in the unused screw hole. The other wire from the motor goes to the fuse holder. (I used a 10 amp fuse, the same as the fuse rating on the car the motor came from). From the fuse holder to the on/off switch, from the on/off switch to the micro switch and finally from the micro switch to the brass rod making the connection with a brass screw into the last unused screw hole. The switches and fuse holder can be obtained from Maplins or car accessory shops. Incidentally if you reverse the + and  wires on the power supply it just makes the motor run in the opposite direction. I have run the motor in both directions and fitted the blade in both directions and as far as I can see it makes no difference what so ever to the performance of the saw. In operation the saw runs reasonably quietly. Its not the fastest thing in the world but sipping tea while a machine does the work for me is a lot better than doing it by hand and Bens a lot happier as well. There is a fair bit of hard work in making this tool but once made cutting metal becomes a pleasure and not a chore. It will of course cut any material that a hacksaw is normally capable of cutting so it is not restricted to metal only.


A FEW AFTER THOUGHTS

The brass pivot that the swinging arm mounts on could do with being bigger. There is some play there which becomes greater at the far end. I had to experiment with large plastic and brass washers too get rid of as much play as possible. It was while clearing up that I noticed the wiper arm spindle is ground and hardened and runs in two bronze bushes in an aluminium housing, this I am sure could be easily adapted to make the swinging arm pivot.

The counter balance spring was a modification as there was too much forward pressure on the saw blade. The photos show experiments with mole grips and lead weights until an ideal balance was found. It was then just a case of finding a spring with the right pull to make the counter balance. This is not an exact science but more a case of playing about until it felt and sounded right. Perhaps if the motor was fitted to the rear of the swinging arm pivot thus forcing the arm to naturally tip backwards would be a better idea. Different weights could then be added to the front of the swinging arm to give the best cut.

The reason for the brackets and studs on the vice jaws is to help hold down larger round tube sections by the use of plastic pull straps. See the photos for an example. Im sure there is a better way but I havent thought of one yet.

An easier way to make the power supply connecting rods would be to use copper pipe (central heating pipe, ½ inch). Flatten one end for about 30mm and bend over at 90 degrees. Drill a couple of holes and screw onto a piece of wood. Make the electrical connection to one of the screws or solder directly onto the copper pipe.

chers

Rich


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