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Tips on 'die'ing?


Jeffds1360
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I decided £10 each for the hardtop hook was ott so got myself a 1/4 die and some nuts for £8. I had some 1/4" round tent pegs and cut them to length. 

Phewph wat a job! It is 50+ years since I died, mind I tapped a lot more recently (don't tell the wife)

What start taper should you use, what fluid to ease the cut? When you feel the bite, do you give it 1/2 a turn & 1/4 back or whop on for a good few turns and a bit back?

I've done 2 out of three in the last couple of hours! Should finish the 3rd I need for T time :)

I now have a spare hardtop....... anyone want? Has an interior light! Very posh. Lots of dosh btw 

20210707_142151.jpg

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there two thoughts on taps and dies   one is continuous turns  the older is back it of to clear the swarf  , that often wrecks the threads by jamming swarf in the cut 

there is a special grease but any grease or oil will aid the cutting.

starting with ataper is what most would do but you really need it parallel cut at the root diameter so its aligned before you start or it will go wonky and yoy

get a devastated cut you wouldnt hang your coat on 

note many die nuts say on them "start other side " as the nut has a lead chamfer 

Pete

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Jeff, no arguement with Pete, but I wonder what your tent pegs were made of?    Steel, but good tent pegs would need to be stiff and strong (they often aren't) so may have been tempered to be much harder than ordinary mild steel, so more difficult to thread.

If you have one left, then annealing it, by heating to red heat, and leaving it to cool in a bucket of sand, would be an interesting experiment as that should return it to its original less hard state.

John

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Thank you both. 

Pete, these are just roof clamps and once the nuts are on, will stay there apart from a bit up and down. I have the option to 'cut' the end off to square it up. I managed to get a square start by use of eye and good judgement :)

John, these pegs are ancient and do not feel tempered, in fact they cut nicely.... I have some modern ones but they are 'twisted' and seem much harder. Pity that I have no tent now :(

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Re cutting a thread I frequently blow through the job/thread with compressed air to clean the swarf out and re oil, agree with Pete going backwards feels terrible, you feel your grinding something!

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8 hours ago, JohnD said:

 

If you have one left, then annealing it, by heating to red heat, and leaving it to cool in a bucket of sand, would be an interesting experiment as that should return it to its original less hard state.

 

It all depends on what the peg is made from whether you will change anything. Personally i would not bother unless i was going to dip it in some carbon to harden it up.

As for cutting, was taught to stop in the cut and back off to break the swalf , then carry on. It again depends  on the feel. Thats where most people go wrong, not feeling how its cutting . Lubrication to keep it cool and ease the cut. You can get cutting fluid or paste. I prefer the paste as it stays where its put and you can see when the work gets hot as it melts.

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😎 cool. That's what I was hoping.  I never did metalwork, only carpentry back in the 60's.

If it feels smooth and sweet, keep going. Like peeling an apple in one cut :)

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Co incidently. I came across half a tube of "rocol" dedicated thread cutting compound, recently. Must have had it over 50 years!. When machine die dutting, we used the old liquid cutting fluid. Aprentice school we where "instructed" in the "Art" of cutting threads, and always told to half turn and back off. The Super would then check your efforts with magnifying glass!!

Pete

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a lot depends on the die nut you are using 

the force to back it a half a turn to break the swarf can jam the next cut 

a continuous turn with a with a eye on the heat generated was what i was taught 

a long time after the apprentice school 

so do what you like that works  

a thread chasing box on the lathe makes life far more reliable but thats not DIY to many 

or   me these days 

Pete

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1 hour ago, Pete Lewis said:

 

so do what you like that works  

a thread chasing box on the lathe makes life far more reliable but thats not DIY to many 

or   me these days 

Pete

Sound advice. I have cut threads on a lathe, but not since college.  Lathe work has mostly been making up shafts to replace worn out ones, and milling keyways! Though we only have a lathe at work, you can get it to do a keyway but its alot of seting up. I have a half decent tap and die set but not split dies, when ever i go about the uk i allways pop into the local second hand tool/ charity shop ect. I have picked up quite a few good tools including imperial taps and dies. Sometimes i don't even know what i would use it for! A good example was when restoring the gearbox recently i found the square 5/16th tool i picked up was just right to undo a selector retaining bolt!

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apart from sets of unf and metric  i have a draw full of taps and dies that would fit something i will never have 

from giant mertic to golden oldie gas and water ones and bicycle   what do you do cant throw them ........... might be useful one day

Pete 

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Mr Henderson, my O'level metal work teacher taught half forward and quarter back. Thats from the early 80's, but as we know what is the norm one moment is the opposite the next.....cough cough to wear a mask or not, look at how the mask fiasco evolved for Covid!!

I think based on all the sound advice give on this forum there is always more than one way to skin a cat. What works for one may not work for another.

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  • 3 weeks later...

Before you start, file a chamfer on the end of the bar; this will make starting easier and also help get the thread straight -you won't be able to tighten up a drunk thread fully. The first few threads will be tapered on the side of the die with the numbers on, so start with that facing downwards. Apply half a turn forward, then a quarter turn back to break off the swarf;  It is best to use a cutting compound, but seeing as you aren't (weren't!) doing many, no point in buying a tin; a dab of grease will do on steel.

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Thank you Patrick. All sorted a few weeks back. Constant rotation with a drop of oil, no reversing, rest to cool every couple of minutes.  Worked well.

Like peeling an apple :)

Anyone need some hard top hooks making up? I enjoyed doing that.

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  • 1 month later...

We always used to use Trefolex paste. Like others. it stays put. If your doing a 'first cut', then use the centre screw on the die holder, to open out the die. On progressive cuts, slack off the centre screw, whilst applying an equal amount of pressure to both outer screws. This should allow you to make finer cuts as you run down to your finish, or major thread diameter. 

One turn on, and a half turn back, was the norm. Paraffin or diesel fuel on the last, finishing cut. It does depend on what you're cutting, but if you think of taps ( with first, second & plug ) but with dies, you shouldn't go far wrong.  

Finally, if your dies do jam or foul, then go back to step one, and adjust to  cut a wider diameter. Or, check your die for loss of teeth, etc. Remember that these are consumable items, and they do wear out!

Cheers,

Ian.

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