# 3/4" Capacity Drill Chuck: Lathe or Mill?



## darkzero (Feb 5, 2015)

I can't decide & would like your guys' input. I scored a very nice USA made Jacobs 18N with no arbor. I never needed a drill chuck with more than 5/8" capacity. What should I get an arbor for, lathe tailstock (MT3) or the mill (R8)? What would I might ever need it for, reamers?

I have a 12x36 lathe & a RF-45 style bench mill. For the lathe I have a 5/8" keyless chuck & a 14N (1/2"). For the mill I have a 1/2" keyless chuck (R8), 14N (R8), & another 14N (1/2" straight arbor). I thought about getting a 5/8" straight arbor for the 18N but it seems kind of puny for it, 3/4"+ straight seems to be the norm for the 18N for straight arbors which I don't want. I was leaning towards MT3 for the lathe but now I'm thinking about going with a R8 arbor. What do you guys think & why?


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## rmack898 (Feb 5, 2015)

I used to have an 18N on my lathe (MT2) but I replaced it with a 16N and it handles 90% of my needs for a tail stock chuck, but sometimes I need to put the 18N that now lives on a drill press back on the lathe. I have an. 18N (R8) that stays with the mill and I have never needed any other chuck for the mill. 

I vote for getting another 18N and making both machines happy.


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## darkzero (Feb 5, 2015)

Ah crap, why did you have to say that! NOw I have to look for another 18N? *Nope don't do it, don't listen to him, you have enough drill chucks. :lmao:

I think I'm set on drill chucks....for now anyway.   I use my keyless chucks most of the time on the lathe & mill. I really only use the keyed chucks for power tapping & for larger drills (not that I ever had a problem with the keyless chucks holding S&D drills). That's kind of why I was thinking the lathe but I never really power tap larger threads, I usually just single point anything 1/2" & larger. I know it's not good practice but sometimes I use an endmill in the lathe to speed up squaring up the bottom of a bore. I'm thinking mill more now but I don't know as I can't think of other uses.


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## 4GSR (Feb 5, 2015)

I have a large assortment of drill chucks, but my favorite "go to" chuck for my 13" lathe is a 16N and second a 18N.  I keep my 20N in reserve for those "impossible" jobs the 18N wont handle.
For my mill, I have several I use, most of the time it is a 5/8" capacity medium duty chuck.  My 16N chucks, which I have several reconditioned one's do not run true enough for mill use. Sometimes use a 1/2" keyless chuck and a 1/4" capacity chuck, too, on the mill.


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## mzayd3 (Feb 5, 2015)

Right or wrong, I have an r-8 to mt3 adapter from my mill.  It takes up a lot of space and I don't use it much for that reason.  I also have a drill chuck with an r-8 taper shank on it that i do use more often.  What I would really like to get is one with a straight shank.


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## Jim2 (Feb 5, 2015)

My equipment is similarly sized to yours.  I run an 18N on the lathe, and a 14N w/ 1/2" straight shank on the mill.  I've had a couple of other chucks when I was getting started, but they're all retired now.  These two get it done for me.  I guess that shows how often I drill small holes as the 18N is limited on the bottom end. . . .  Mostly I drive Silver & Deming style drills w/ a 1/2" collet in the mill for the larger stuff.

Jim


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## kd4gij (Feb 5, 2015)

I would put the 18N on the lathe. I use collets or endmill holders for anything over 1/2" in the mill.


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## darkzero (Feb 5, 2015)

Thanks. I'm still undecided. What kind of tooling are you guys using with 3/4"-1" drill chucks? I use S&D drills so the shanks are 1/2". I've never needed a drill chuck over 5/8" yet so I'm trying to get an idea.

Mzayd3, yeah I have a couple of those R8-MT3 adapters. I chopped one up to use for something else but I did keep one for use in the mill just in case. I never used it though & yeah it would be sticking out from the spindle a lot.


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## Kevin45 (Feb 18, 2015)

Just out of personal preference, I would get an arbor to fit the lathe. Most of the time, you will have a collet to fit your mill that has a large diameter cutter, but for a lathe, if you want to drill a large hole with a drill....1/2" is about the standard. The larger you can get for the lathe the better. You may still have to turn down the shank some, but it would be nice to put in a 3/4" drill into a lathe without having to modify the drill. In a mill, you can easily use a 3/4" collet to put a drill in. Plus depending on what you are making in a lathe, if it takes a large hole, the larger you can start out with the better before switching over to a boring bar. If you can pop in a 3/4" hole in a lathe, you can start out with a large beefy boring bar to start out with, without having to work your way up. My vote is for getting a lathe arbor


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## Andre (Feb 18, 2015)

I'd put it on the mill, large drills in a lathe you really want a taper shank. You won't find many R8 taper shank drills!


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## darkzero (Feb 18, 2015)

Kevin45 said:


> Just out of personal preference, I would get an arbor to fit the lathe. Most of the time, you will have a collet to fit your mill that has a large diameter cutter, but for a lathe, if you want to drill a large hole with a drill....1/2" is about the standard. The larger you can get for the lathe the better. You may still have to turn down the shank some, but it would be nice to put in a 3/4" drill into a lathe without having to modify the drill. In a mill, you can easily use a 3/4" collet to put a drill in. Plus depending on what you are making in a lathe, if it takes a large hole, the larger you can start out with the better before switching over to a boring bar. If you can pop in a 3/4" hole in a lathe, you can start out with a large beefy boring bar to start out with, without having to work your way up. My vote is for getting a lathe arbor



Although I was leaning towards the lathe, I decided to go with the mill & I already got the R8 arbor for it. Thanks for all the suggestions. All my drills currently over 1/2" are S&D drills which have reduced shanks (1/2"). My current largest is 1" but a few larger is on my list. I can't go too large as the slowest speed on my lathe is 60 RPM which is not good for some of the materials I drill. The only straight size shank drill I have is 15.5mm but I turned it down to a 1/2" shank. But I got a 5/8" capacity drill chuck when I got my current lathe so that would have fit anyway.

Use of non-fractional reamers if ever needed is why I choose to go with the mill. And I could always move a part from the lathe to the mill to use it, not so much the other way. I had asked what other reasons for using a larger drill chuck on the lathe were but no one suggested anything. So I just went with the mill.



Andre said:


> I'd put it on the mill, large drills in a lathe you really want a taper shank. You won't find many R8 taper shank drills!



Exactly my thought, some taper shank drills are what I have on my list to buy so unless I run into another reason. I hate when the drill chuck falls off the arbor taper when using larger drills (well not often, only happened to me once ) I think the larger drill chuck will be more useful on the mill for me.


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