making QCTP holders for my mini lathe

[MCRIPPPer]

here are some pix of some tool holders i am making for my 7x12. these are for the a2z cnc tool post. last weekend i started hack sawing the 1x1 aluminum pieces, and i got my dovetail cutter on monday, and now i have 10 tool holders today! or at least have the dovetails cut in 10 pieces. i have 6 completed blocks that just need adjuster nuts, and 4 blank ones.



here is my modified tool post. i drilled the hub to m6 at an angle so that the handle is higher and out of the way, and made a new handle. i also made new pistons for the tool post so it locks in the 45 degree position weather i use the turning or boring dovetail, just like a real toolpost! also made a new bushing/"mounting kit" for it with a better fit. i will get pics of the tool post mods if anyone is interested.



fits just like an original.

 

[CNC Dude]

Wow! Those look awesome! I too use the A2Z tool post and had considered building my own tool holders. What dove tail should I get? I have never done any dove tailing, so have no idea what to look for. I imagine it is a matter of the angle and the diameter, right?

Good job!

 

[aforsman]

I also have the same setup and have considered trying to make some extra tool holders myself, so the info on the cutter used would be great. I'm not quite sure I understood the mods you made to the toolpost (yes, I'm a little slow sometimes )) - could you elaborate on exactly what you did and how it helps. Some pics of the individual modified pieces would be helpful. Thanks.

Allen

 

[MCRIPPPer]

thanks guys. the dovetail cutter is a 60 degree 3/4 inch diameter, from little machine shop. it cost about 15 dollars. i took .010" cuts conventional milling, with wd40. first i mill the slot to .850, and .202" then start going with the dovetail cutter. touch the dovetail cutter to the surface and zero, go about .002 up. i like to work from the center so i think it was .126 each way (movement of cutter each way). depending on the exact diameter and sharpening you will need to test fit before you know your numbers. i still test fit each one just in case. basically i milled them intil the dovetails were a pretty good fit, with a small amount of play. then, while still on the vise, switch to a 1/2 inch end mill, test tool post in dovetail and see where the handle lines up. if you are careful with the machining of the dovetail, you will have some room for adjustment still. this is why i machine the slot exactly .200 plus a little. mill the center of the slot .001 at a time until the handle locks where you want it. this is where my mods come in. you know how the 10mm bolt fits very loosely through the bishing, and through the hole in the tool post body, so yuo can see the problem of these pieces becoming out of alignment when assembled. and there is slop between the rotating drum and the body as well, so when you tightne the handle, it pushes away and flexes the bolt, because there is no support. and when you loosen the bolt when you have a tool holder on it, the adjustment changes and now the handle engages at a different point. so i very carefully drilled the hole in the main body out to 1/2 inch, and machined a new bushing/hub with less slop, and a 1/2 diameter section which now keeps everything concentric. then i put the cam drum between centers and turned a little bit off of the upper part(not the cam, but the part that is supposed to fit the 1" diameter in the main tool post body). i made a pvc bushing which pressed on, then back between centers to make it the perfect diameter. now my tool post handle always engages at the same point, and it works without being bolted to the lathe, so i can accurately check the tool holders as i make them.

 

[MCRIPPPer]

ok, here we go.

you can see the new bushing with the smaller diameter section that engages the drilled out tool post.





also notice the bushing on the cam. that is just sharpie on it.

as you can see the modified tool post with new pistons engages in the correct position for both tool positions.

 

[aforsman]

Nice work! Thanks for the additional info.

 

[road]

Those are nice pieces and some good info.
I have been considering this for my 7x10
I am going to be cutting out a few blocks of aluminum tonight

tks

 

[MCRIPPPer]

thanks. if you need any more measurements or info i will be glad to share.

glad i inspired someone to make some tool holders! i made $200 worth of tooling for about $25.