todays stuff up

**texx** · 28th July 2013, 10:38 PM

this is my stuff up for the day.actually day and a halfs work with interuptions and all .
i am making a er32 collet chuck with a 5mt on the end so i can go straight into my headstock ( 5mt ) with no adapters or sleeves ( i already have an er32 chuck on a 2mt for my wood lathe and a full set of collets .
any all was going well i cut the the stock to the length ( chunk of 4140 that i bought for the job ) i machined the thread on one end for the draw bar which will be 1"nb pipe machined the 5mt taper ( came out quite nice too ) bored a hole right through the full length of the stock 22mm dia gives me a bit of clearance the biggest collet i have is 20mm plan is i will be able to put material right through the chuck and headstock up to the diameter of the biggest collet , anyway up to this point every thing went to plan the it hit the fan whe i took off the 3 jaw and turned the job the other way around and mounted it in the lathe on its own new taper the way it will be used when finished , all that i have to do is machine the thread for the collet nut and cut the internal collet taper and that where it hit the fan with the job mounted in the headstock taper i dont have enough travel left to cut the 40 x 1.5 thread for the chuck nut , with the cross slide comes to the end of travel and hits the headstock about 20mm to early with the compound set on 29 degrees . i cant hold the thing in any other chuck to cut the threads cos it all tapered except for the thread on the other end where the draw bar screws on and i dont thing i will be able to hold the work by that thread . dont know if you follow what i mean but thats the best i can do to explain it .
anyway end result is that tomorrow i scrap the whole thing and start again with a new one . good thing is second time around i should make a much better job of it having had some practice now . plan is to make the whole thing 2 inches longer so when mounted in the taper there is more room to work .

johno

**jack620** · 28th July 2013, 10:54 PM

Johno,
If you post a pic someone might be able to nut-out a solution for you.

**Stustoys** · 28th July 2013, 11:01 PM

Hi Johno,
As Jack said a picture would help.
First thing, forget the 29 deg compound angle. Can you make it then?

Stuart

**nearnexus** · 28th July 2013, 11:03 PM

If I read this right, with the taper in the spindle, you haven't got enough travel to cut the thread for the collet nut ?

Why not make up a reverse direction boring bar for the toolpost with a 60 degree tip to cut the external thread ?

I did something similar on a big job once when I ran out of reach and travel.

Rob

**texx** · 29th July 2013, 08:54 AM

Originally Posted by Stustoys

Hi Johno,
As Jack said a picture would help.
First thing, forget the 29 deg compound angle. Can you make it then?

Stuart

just checked and yeah i can reach far enough without the 29deg angle and still have a few mm to spare if i put the compound parallel to the bed and screw it to the left to its full travel .
so i suppose i could cut the thread plunge cut style .from what i have read about plunge cutting threads i thought it was something to stay away from ,however with the work in so close to the headstock chatter should not be a problem . i will have to go very small cuts i should think , i am only using ground hss tool and i am cutting 4140.

johno

**pipeclay** · 29th July 2013, 01:03 PM

Its only a 1.5 pitch thread but you may want to allow a little extra movement in your compound for advancing the tool towards the headstock slightly when cutting the thread.
It would only need to be .5 to 1mm of travel.
Will you be using a chasing dial or reversing the spindle.

**Stustoys** · 29th July 2013, 01:30 PM

Hi Johno,
Now you could do some trig and work out how much compound feed for how much cross slide feed so you get a tool movement of 29degrees.
If you compound half your cross silde I get an angle of 26.6(haven't tried that myself).
Personally I just move the compound back and forth.

Stuart

**texx** · 29th July 2013, 02:10 PM

thanks for the replies fellas . but i got her done . set every thing up at 90 degrees and just cut straight in with the cross slide . only cut a few thou at a time i didnt think i would be able to cut straight in like that using hss on 4140 but it went just fine so all good , the method i use for thread cutting is once the half nuts are in they stay in untill the thread is finished . at the end of each cut i stop ,wind out ,reverse, reset and go again , same way a bloke on you tube does it ( doubleboost , is his name , ).anyway thread turned out quite good just have to cut the internal taper for the collets now and it should be ready to use . i do need to get another er32 closure nut though cos i dont want to share one between to chucks .

johno

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