Author Topic: Box tool again  (Read 3366 times)

Offline shipto

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Box tool again
« on: August 21, 2022, 02:56:50 PM »
I am currently working on a project that requires a 7mm LH screw (hence the reason I needed to reverse my lathe) and found that I cannot get 7mm bright drawn so would have to reduce 8mm to 7mm.
There are reasons I didnt want to just turn it down the easy way so I opted for a box tool again but this time I didn't want to have one mounted in the tool holder because there is a number of operations which I want all setup on the lathe at the same time.
Anyway enough waffling I found a scrap bar which would suffice (not sure what I was doing with it before but never mind)
I turned a 16mm shaft onto it, when I got to the hole and saw cuts I got a bit worried about thinning material down so much that it bent and damaged something so used the hacksaw to get rid of them.
After the shaft was to size I drilled a 9mm hole right through it.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
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Offline shipto

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Re: Box tool again
« Reply #1 on: August 21, 2022, 03:06:58 PM »
Next I drilled a hole to accept a 3mm needle bearing which will act as a pivot point to allow me to centre the tool and I milled (quite badly, dont judge  :lol:) the opening for the cutting tool. A channel to clear the swarf was also needed PIC2 but after taking this picture I realised I had not milled deep enough so put it back on the mill to remove more.
Last pic shows the tool in place, as you can see the two top screws can adjust the tip up or down as needed while the back one sets the depth of cut.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
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Offline shipto

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Re: Box tool again
« Reply #2 on: August 21, 2022, 03:20:46 PM »
Now I moved on to the front for it which holds the bar secure. I broke a tap in the first hole but managed to remove it thankfully.
Heres a couple of pictures with it mount in my MT3 turret attachment and I have to say it works a treat I tried to get a pic with the diehead mounted on the turret too but phone is not cooperating for some reason.

So my process to make my 7mm LH screws is cross slide in with a stop set in one tool post, withdraw bar to stop and tighten collet, reduce bar with box tool, flick lathe into reverse and cut threads with the diehead on rough cut then finish cut, and finally part off the screw with parting tool mounted on qctp.
Nice and easy and takes just over a minute each.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline shipto

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Re: Box tool again
« Reply #3 on: August 22, 2022, 04:43:26 PM »
Got phone to cooperate and heres a pic with the diehead on the turret along with the results of 25 minutes work  :D. There is a slight problem with the box tool in that the first 10mm or so curls up the swarf in such a way that it gets pushed into the shaft so I have to remove it after 3 or 4 to clear it but I think grinding the tool differently will solve this problem.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline pycoed

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Re: Box tool again
« Reply #4 on: August 23, 2022, 04:37:22 AM »
A very satisfying looking project  :clap:, the value of which would sadly be lost on 99% of the population these days (or am I just being a cynical old curmudgeon?)

Offline shipto

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Re: Box tool again
« Reply #5 on: August 23, 2022, 04:07:59 PM »
A very satisfying looking project  :clap:, the value of which would sadly be lost on 99% of the population these days (or am I just being a cynical old curmudgeon?)
I dont know there are bound to be some small batch machine shops around the world that still use them but we are in the age of CNC now so any great numbers of parts are not going to be made by someone stood at a manual lathe anymore. I only found out about them because my wifes work asked me to make some screws for the dieheads I refurbish for them and as you can imagine turning 1/4" bar down to 1/8" or thereabouts would have been a nightmare on my Harrison.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline pycoed

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Re: Box tool again
« Reply #6 on: August 24, 2022, 04:16:05 AM »
Re 1/4 to 1/8: I know exactly what you mean! Only yesterday I could have done with a box tool, since I needed to turn down an M10 bolt  to .200" for just over 1" then taper down to .067 over the last .25". No dimensions critical - it was just a pressure release for a log splitter jack, but it took me 3 goes to do it (1/2" at a time did it).