[How do I?] Mill A Dovetail

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MattM

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I want to mill about a two inch dovetail in 12L14. I've never done this before. How do I proceed? I have a new .75"x45degree cutter. Do I first mill a slot then run the cutter or just plunge right in?
 
MattM said:
I want to mill about a two inch dovetail in 12L14. I've never done this before. How do I proceed? I have a new .75"x45degree cutter. Do I first mill a slot then run the cutter or just plunge right in?
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Dovetail cutters are fragile. I believe that it is best to remove as much material as possible with regular endmills, then finish with the dovetail cutter. Be careful about feeds and speeds, and hold the workpiece as rigidly as possible.
 
owl said:
Dovetail cutters are fragile. I believe that it is best to remove as much material as possible with regular endmills, then finish with the dovetail cutter. Be careful about feeds and speeds, and hold the workpiece as rigidly as possible.
Click to expand...

Would it be best to feed on the X or Y axis? Feed manually and use lots of cutting oil? I will mill the slot with an endmill before employing the cutter.
 
Take a look at this video
and the next two in the series. Tubal Cain (aka Mr. Pete 222) does a nice job of explaining all the steps.
 
I don't mean to accuse, or offend . If you are planning on milling anything for guns, say a sight dovetail, most are 60* not 45*. If it's for something else disregard my comment. Wouldn't want to see you make a nice sight then mill the wrong angle dovetail on it if it could've been avoided. :)
 
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12L14 is very easy to machine. Yes, I would feed by hand, so you can “feel” the cutting. A little cutting oil is a good thing. Also, as mentioned, removing most of the material with an end mill is wise, sometimes necessary. Try to avoid climb milling, if you can’t, tighten the gib(s)…Dave.
 
What is it for? QCTP are also 60deg. The tips of dove tail cutters are fragile as said. I always mill the center out with an end mill then use a 3/16 T slot cutter or key seat cutter. And then the dove tail cutter.
 
kd4gij said:
What is it for? QCTP are also 60deg. The tips of dove tail cutters are fragile as said. I always mill the center out with an end mill then use a 3/16 T slot cutter or key seat cutter. And then the dove tail cutter.
Click to expand...

I am trying to make the thread cutting device as illustrated in the July/August issue of Home Shop Machinist (page 35). This will stretch the envelope of my skill level. It is the most difficult project I have attempted. Most here could bat it out between farts. It will take me days and more than a few starts. At $.50 a lb at he local scrap yard I can afford a few mistakes. They didn't have 12L14 so I picked up a two foot piece of what looked like hot finish but after clean up looks more like cold. It machines beautifully, maybe 1018?

I did mill the slot and the dovetail cutter worked fine. I went slow with plenty of cutting oil.
 
Be sure to calculate your spindle speeds.
Double check your clamps or vise. Be sure that she doesn't shift on you.
Listen to the mill talk. She will tell you if something is wrong.

Daryl
MN
 
Don't worry, it's not the end of the world if you knock the corners off the dovetail cutter. There's a few of us here that will be glad to setup and re-grind the tips a little to produce a cutting edge for the next time its needed.
 
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