First! i hope many to come.
well, the title says it all, i needed to cut some pipe threads for my new bed (yet another pipe bed) and i didn't wan't to invest money in a new vise with a pipe holding jaw, mainly because i alredy have a pretty heavy vise which suits most of my needs.
so, i proceded to find a way. tried pieces of cloth on the vise to have a better grip, then tried adding shellac to the cloth to make it 'stickier', then i made rubber jaws for my vise. none worked. finally i devised a simple method with tools most people alredy have lying around, and if they don't they really should make/buy (i often make even though it costs more, because it's fun!)
you'll need a heavy vise ideally, you could do around that using a fulcrum of some sort but if the pipe keeps sliping that will bother you to death, cutting threads is alredy hard enough.
the second tool is a pipe wrench. yes! a pipe wrench! turns out an instrument used to apply huge ammounts of torque is also the ideal instrument to resist applied torque. and really, the hard part of cutting pipe threads is the torque which causes the pipe to slip in the vise.
third tool is the threading die. this one is pretty straightforward, you need a die to cut the threads unless you want to file them (not since maudslay we don't!). you need to buy/make/rent a die and a threading kit (the turning thingy). mine is 1/2".
fourth tool is cutting oil. i use lard. that may sound retrograde but it actually has great adhering and lubricating properties. in fact, some machining oils still use lard in the mix even today. i advocate it's use because
1º it's enviromentaly friendly, lard is a byproduct and it is completely biodegradable and relatively non-toxic, unlike many cutting oils
2º it's cheap. the small cup you'll see me using in this instructable was made by myself and it cost me almost nothing
3º acessible to the hobbyist and still provides great, just as good, results as anything else.
well, let's get to it!
well, the title says it all, i needed to cut some pipe threads for my new bed (yet another pipe bed) and i didn't wan't to invest money in a new vise with a pipe holding jaw, mainly because i alredy have a pretty heavy vise which suits most of my needs.
so, i proceded to find a way. tried pieces of cloth on the vise to have a better grip, then tried adding shellac to the cloth to make it 'stickier', then i made rubber jaws for my vise. none worked. finally i devised a simple method with tools most people alredy have lying around, and if they don't they really should make/buy (i often make even though it costs more, because it's fun!)
you'll need a heavy vise ideally, you could do around that using a fulcrum of some sort but if the pipe keeps sliping that will bother you to death, cutting threads is alredy hard enough.
the second tool is a pipe wrench. yes! a pipe wrench! turns out an instrument used to apply huge ammounts of torque is also the ideal instrument to resist applied torque. and really, the hard part of cutting pipe threads is the torque which causes the pipe to slip in the vise.
third tool is the threading die. this one is pretty straightforward, you need a die to cut the threads unless you want to file them (not since maudslay we don't!). you need to buy/make/rent a die and a threading kit (the turning thingy). mine is 1/2".
fourth tool is cutting oil. i use lard. that may sound retrograde but it actually has great adhering and lubricating properties. in fact, some machining oils still use lard in the mix even today. i advocate it's use because
1º it's enviromentaly friendly, lard is a byproduct and it is completely biodegradable and relatively non-toxic, unlike many cutting oils
2º it's cheap. the small cup you'll see me using in this instructable was made by myself and it cost me almost nothing
3º acessible to the hobbyist and still provides great, just as good, results as anything else.
well, let's get to it!
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Signing UpStep 1: Setting things up
First you'll need to measure, mark, and cut the pipe to lengh.
measure twice, cut once. (that saved me today while i was cutting these)
be sure you are cutting square, you don't have to be absolute about it but some care makes the threads come out better and makes work easier.
i like to lubricate the blade of the hacksaw (guess i didn't mention this tool, duh) it makes it MUCH easier to cut, the lard beatifully adheres and doesn't drip (try finding a cutting oil which will do that). also , the lard won't stay solid as people may think, it sort of liquefies on contact with metal (my guess is that the metal's ability to transfer heat fast is the responsible, but i digress)
after you cut, take down the edges with a file and make up for any imperfections in the cut.
i know most of you all know this, but bear with me, someone might not know that so i'm including every step except the stuff you can figure by yourself(not going to take all of the fun out).
lube it up and it is ready to tap!
measure twice, cut once. (that saved me today while i was cutting these)
be sure you are cutting square, you don't have to be absolute about it but some care makes the threads come out better and makes work easier.
i like to lubricate the blade of the hacksaw (guess i didn't mention this tool, duh) it makes it MUCH easier to cut, the lard beatifully adheres and doesn't drip (try finding a cutting oil which will do that). also , the lard won't stay solid as people may think, it sort of liquefies on contact with metal (my guess is that the metal's ability to transfer heat fast is the responsible, but i digress)
after you cut, take down the edges with a file and make up for any imperfections in the cut.
i know most of you all know this, but bear with me, someone might not know that so i'm including every step except the stuff you can figure by yourself(not going to take all of the fun out).
lube it up and it is ready to tap!
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One question.
Is lard the same as bacon grease?
My wife throws that out a lot.
Thanks.
rich
so they're similar. but bacon is salted and smoked, so there will be some corrosive salts in the result as Iperkins said.
i'm thinking about putting up a ible on rendering lard. what do you guys think?
Many will thread when you buy the pipe.. not all.
Using a tap or die set to cut threads (taps cut threads on the inside, a die puts threads on the outside), it works well to go forward a half turn at a time, followed by a quarter turn backwards.
This helps by allowing the bits of cut metal to be drawn back into the recesses of the cutting tool and ease the binding that occurs. It also reduces heat a bit, which keeps the pipe from expanding and causing even more binding, and makes for more precisely-fitting threads.
Nice Instructable! I love the lard tip, that's awesome!
In general, one should cut about one turn, then back off a bit to break the cut bit off, then cut another turn. Use this time to put a bit more cutting oil on the threads - too much is much better than not enough (practice will tell you when you have enough but not too much).
You want to use about the same amount of force on each cutting turn. If it gets really hard to turn, you need to back off, apply oil, and start the next turn.
Any reasonably good oil will work - ie 30 weight engine oil. The oil lubes the cutting edge and keeps things cool. Higher speed (ie drilling into steel) needs oil. Cutting oil is specifically made for the high-speed cutting.
The poster uses lard - it will do in a pinch, although motor oil would be easier.
So - in general, a good idea. You can use two wrenches to create a "tripod" with the pipe, then lash/clamp the whole thing solid to a workbench.
For cutting the pipe you can drill a pipe sized hole through a piece of wood, 4by probably best. Then rip down in line with that hole. Next drill a smaller hole below the first at 90 degrees and rip down to that. Slip the pipe through its hole and clamp across so it holds it tight, saw goes down the other rip which keeps it at 90 degrees. If you line the pipe hole with sand paper it will give a better grip and so use it as a pipe vise.
Good practice is to deburr the inside of the pipe after threading, a file tang works well enough as a reamer.
i didn't deburr because this was 'structural' pipes, nothing will pass inside them. but i did have to deburr and knock down the edges on some of them so they would thread onto the fittings easier.
You can drill and bolt the timber to the bench top (or whatever) and then remove the plywood spacer/s and bolt or clamp the two pieces together.
Although the true compressive grip of dry oil free wood on dry oil free wood, is not astromically high, the lenght of the grip area, and the amount of wooden vices that can be used, you can lock them lenght of pipe up pretty tight with the wooden vice.
Be sure to use a few LARGE THICK washers with small holes, under the bolt head and nut, if using bolts to clamp the wooden vice jaws together.
i certainly am right with you on backing out the tap/die so you can clear the chips but i didn't feel the need on this one, they were just curling out perfectly.
what i meant to say is that there aren't really any great dangers such as things falling and crushing my feet or splatter( as in welding). but you're right to point out safety is always welcome.
By the way, nice work.
i'll eventually make wooden jaws as well as soft metal ones(alu).
so far i had 3 failures mid-project and managed to loose a tooth. does this mean i can apply for the redneck challenge? lol.
but it is coming along!
CHALLENGE ACCEPTED