# An O1 Dovetail Cutter, Some Qctp Holders And A Tool Post Mounted Drill



## mattthemuppet2 (Jun 11, 2016)

next on the list now that my DP/ mill is more capable (treadmill motor conversion) is to make more QCTP holders. I only have 2 turning, 1 parting and 1 boring holder and I'm always swapping tools in and out of them, which rather defeats the purpose.

I wanted to make a couple out of alu first to get a hang of making the dovetail, so came up with a toolpost mounted/ drill driven drill chuck and some other bits'n'bobs. I also wanted to try my hand at making a dovetail cutter to see if I can make that work for alu and perhaps steel.

O1 cutter, using 1/2 rod

end grooved to 0.270in, with 0.2in left at the end, which was then turned down using the compound set to 60deg. End was faced with the compound set to 2deg, to give it a bit of end relief




in the collet block in the DP, with the non-collet end tilted up a bit to give 2deg relief on the flutes. Flutes were cut 0.5mm (whatever that is in inches) below center, which should give enough side relief.



unfortunately one of the cuts dug in (this whole thing is flex-o-rama), kicked the whole table sideways and walked across the face of the dovetail cutter. Bugger. It's now a 2 and a half flute cutter 




anyway, thought I'd try hardening it anyway. Stoned the edges (what there were at least), heated it in the toaster oven to 400F, then heated it with my propane torch til the cutter end glowed dull red then dunked it in powersteering fluid. Fished it out, stuck it back in the toaster oven at 300F for 10min, stoned the edges again and had a crack. Most of the material was removed with a roughing end mill, then the dovetails done with this.




it worked ok, although it was wearing pretty fast. Might have been running too fast (900rpm sounded nice), might not have actually hardened it. Next time I'll use a magnet to check.

Now I need to cut out the recess for the drill chuck, but my arms are dead from a 5h bike ride today so I'll be watching Zootopia with the kids instead


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## Bob Korves (Jun 12, 2016)

Look at Randy Richard's YouTube channel for how he makes his dovetail cutters that he sells.  There are several videos on the subject, and drawings are in his Dropbox.  It is a single carbide insert cutter using a TPGB321 insert.  They work very well and he uses his at above 2000 rpm, beautiful finish.  It is not too difficult to make.
https://www.youtube.com/user/Catfish6945/videos


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## LucknowKen (Jun 12, 2016)

Nice tutorial. Thanks Matt.


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## Chipper5783 (Jun 12, 2016)

Here is my dovetail offering.  I made additional holders for my QCTP (CXA size) because I had some 1" tools and the standard holders only accept 3/4" tools.  I made the new holders out of mild steel plate.  When dovetail was approaching full depth, it seemed I could only take very small cuts (which makes sense).


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## mattthemuppet2 (Jun 12, 2016)

thanks Ken!

great food Bob, I'd thought about carbide, especially a tpg insert. the reason i didn't is that my set up (xy vise on a drill press with a collet chuck) is super flexible and i thought it would chip the insert almost immediately. I'll definitely keep it in mind though!


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## mattthemuppet2 (Jun 12, 2016)

awesome work David, that cutter looks professional! I'll have to do some measuring and see if an insert would even fit. the dovetail on my qctp is 5mm/ 3/16in deep and the gap is 21mm/ 3/4in wide.


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## mattthemuppet2 (Jun 13, 2016)

finished the body of the drill chuck holder

chunks hacksawed off



milled square with a really long 1/2in end mill



drilled with a 9/16 drill in one go, 200rpm on my high speed pulley, which I was super impressed with. Then reamed with a 19/32 reamer and then 5/8 expansion reamer



1/2in bushings pressed in, oil hole drilled and tapped, height adjustment screw hole drilled and tapped



now I need to turn and thread the shaft that'll go through the block and hold the drill chuck


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## Charles Spencer (Jun 13, 2016)

Matt, before I got my mill I was working on using an old Atlas drill press and an xy vise for milling.  I did some research and found  a pretty good idea from an old 1950s Popular Mechanics.


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## mattthemuppet2 (Jun 14, 2016)

thanks Charles, I saw that a while back. Not a bad idea either, although it wouldn't do much for left-right cutting. I try and set up everything so that the quill is extended as little as possible, which helps, but it's never going to be a proper mill.

Started work on the shaft last night. Used a shaft from an old washing machine motor (yay hydraulic press!) which cut like a dream. Some of the nicest steel I've worked with. Turned one end down to 3/8in and used the drill press and my hex collet chuck to mill 3 flats on it. Put the chuck back on the lathe and started turning it down to 1/2in to fit the bushings. Once that's done, I'll flip it around, turn down to 1/2in and thread it 1/2-20


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## mattthemuppet2 (Jun 15, 2016)

finished!

shaft turned down to 0.499in (tried for 0.500, overshot), turned around in the chuck and turned/ threaded 1/2-20




assembled! Used a spare 1/2in shaft collar I had lying around



complete with old Jacobs Multicraft chuck I picked up at a garage sale at some point. It's not very good, but it'll do for now.



mounted for cross drilling (remove the height screw and flip to face drill)



ta da!



I think I'll spend the next few days giving my mountain bike a service, then start on DTI holders.


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## Bob Korves (Jun 15, 2016)

Nice work, Matt, with limited resources...   (!)


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## mattthemuppet2 (Jun 15, 2016)

Thanks Bob, I'm pretty pleased with it! Looking for a smaller chuck (1/4 or 3/8) though as this has limited space between chuck and shaft on my small lathe. Might make up another shaft with 3/8-24 threads to expand my options.


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## mattthemuppet2 (Jun 17, 2016)

got sidetracked making a DTI holder yesterday  Got even MORE sidetracked figuring out how to cut 0.5mm pitch threads on my Atlas, which involved several hours of staring at the threading chart (think I understand it now) and then 10min using nthreadp to calculate the gears I needed.

my super awesome Scherr Tumico metric DTI had a 4mm shaft with M4x0.5 threads, whereas my workaday Gem DTI (eternal thanks to Vancbiker) has a 1/4in shaft, so I thought I'd take the "easy" route of making a new 1/4in with M4x0.5 threads. Hah, some easy route. Anyway, after a number of hours, here it is! Printer shafts make lovely material, although the threads are a little loose as my threading tool has a nose radius for larger threads.



installed



the DTI that will live in it



I really should do some bike maintenance, but I also really want to make some toolholders..


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