Drill Press Speed

silver_pilate

silver_pilate

Joined
Oct 30, 2002
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As I'm tired of burning up larger drill bits, I'm considering getting a free-standing multi-speed drill press. I'm curious about what is a good low speed to look for. I believe the press I have right now goes down to either 650 or 700rpm at it's slowest (if that), and for larger bits, I'd like to be able to go even slower to allow the bit to bite and not chatter. On top of that, I need the extra rigidity of a larger drill press.

So is 300 rpm typical of the lower end for a 12 speed drill press? Any luck with the HF presses? I know you get what you pay for...how about Delta?

--nathan
 
Why not indeed? I've tried but have a difficult time getting it just right. That's fine, but I'd like to be able to avoid burning them out super fast in the first place. :D

--nathan
 
Nathan, are there any used machinery places near you?
I use an old Turner turret press that's prolly 70 or 80 yrs old and drills anything I want from 1" down to less than a sixteenth. It will drill bigger if I use bigger collets.It;s still good and tight and speeds are adjustable with the flat belt system. Might be worth looking into.
 
For 1/4 inch bits in mild steel120 RPM is good, for 1/2 inch bits I like 60 RPM my 7/8 inch bit I usually faceplate whatever I'm drilling on the lathe and throttle back to about 10 RPM,

Lots of oil. If it's smoking, it's too hot, slow it down

-Page
 
Unfortunately, there's not a lot of used machinery stores around here. :( I'll take a look, but for the most part, you're stuck with pawn shops who charge 3x what they're worth. There is one used machinery store I know of, but the stuff tends to be pretty hard used and worn out (and overpriced). I may keep an eye to ebay but you don't know what you're going to get.

--nathan
 
My Sears craftsman goes down to 390 and maybe one speed slower . 5/8 chuck . I use lots of oil and have been using the same cheap drill bits for 5 yrs. plus .
 
Just looked it up . Home Depot has a Rigid 15" floor model with free shipping for $300.00.
 
I have been wondering the same thing myself too.

i ripped off this chart
(that doesn't copy paste well at all)
http://curiousinventor.com/guides/Metal_Working/Drill_Speeds

Rotation Speed (RPMs) = (3.82) * SFM / Dia. SFM = (.26) * RPM * dia.
mild steel at 100sfm and toolsteel at 50 sfm

that lists 1/2 mild steel at 784 rpm
that lists 1/2 tool steel at 382 rpm

I did the ratio calculations of my drill press pulley to a 40% speed of 1740 which is about 700rpm

so that puts most drill presses limited to 1/2 mild steel

Apparently the only ones that will go lower have a 3 shaft pulley system, and those are all much more $. I haven't seen one in an import(doesn't mean there are none)

...so look for a 3 pulley speed system ?
 
The local Lowes has THIS 12 speed drill press. Not sure how many HP a "8 Amp" motor is :rolleyes:, but I'm thinking 1/2 hp.

Anyone have any experiences with this drill? Of course, they never have runout spec'd, but I fully extended the press and checked at the chuck for wobble, and it didn't budge a bit. Of course, this was not under power. However, I did feel another Ridgid press at another store, and there was a good bit of wobble once the drill was extended beyond 1/2 way.

--nathan
 
I've been drilling 1/4" and 1/2" mild steel lately. Today I had to get through a piece over 2" thick. It's a challenge to do with my little yard-sale Craftsman drill press. The slowest it can be stepped down to is 620 rpm. Couple that with a wimpy motor, funky vise/clamps and an amateur sharpening bits :o and it's anybody guess how long it will take to drill the pieces for a job. I won't say anything about how round the holes and/or straight the holes will be when all is said and done. BTW, I have fallen in love with step bits!

I've been keeping my eye out for a used floor press, but they don't come up very often. Whenever I do get a hold of a good one, I'm considering setting it up with a variable speed reversing motor and controller.
 
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For what it is worth, the eye holes in the Tai Goo hammers are drilled out with a 3/4" drill turning 400 RPM. About six pecks in two inches in 4150. That drill has cut many pounds of chips without resharpening.

For comparison, a 3/8 drill (half that size) would turn at 800 RPM (twice that speed).

I sometimes drill 3/8" holes in D2 at 1000 RPM. Kinda fast, but the machine I run that part on doesn't have the best torque curve at low speeds. As long as your chip thickness is still correct you can sometimes get away with bending the SFM rules a little. Meaning you need to feed it pretty hard.

There is no reason to turn extremely slow if you have a decently rigid setup. Chatter can be a symptom of underfeeding. And rubbing dulls cutters too.

A nice heavy old drill press with flood coolant will blow your mind with its material removal rate. And a good old mill is just as good for that and more versatile.
 
Yeah, a major problem with my setup is flex. The 12" craftsman just isn't rigid enough for heavy drilling. One thing I like about that Porter-cable is it has a stout table which clamps down well. When I try to increase feed pressure on my drill, it just flexes and chatters.

I may go ahead a pick this one up and see how it does as I still have some gift cards to Lowes laying around somehwere. I'll probably upgrade to a keyless chuck as well eventually. If I get it, I'll let you guys know how it goes.

--nathan
 
The Grizzly 7944 goes down to 140, which is very, very handy.

It's no 1950's US-made DP, but it's a good machine for the money.

Dave
 
Nathan,

I've got the Rigid 15" Floor model as does another maker I know with no problems. It goes down to 300 RPM.

I'm certainly not qualified to judge flex or anything else but it turns the bit with no problem. FWIW I typically just keep mine set on 300 rpm but changing speeds is a snap with this model at least.

I chose this one mostly because we had one at my last job so I was familiar with it already.

-Josh
 
Well, I did end up getting the Porter-Cable. It's a 12 speed 15" drill press that runs down to 300 rpm. Definitely a solid machine. It's spindle is very tight in tolerance, and it seems pretty well built. The only complaints are that the base isn't quite heavy enough for my likes and tends to wobble a bit. I'll have to put some weight on it for now until I build my own shop and can bolt it to the floor.

I went ahead and installed the keyed chuck that came with the press. It's definitely a better chuck than my Craftsman drill press, but I'll eventually install a keyless precision chuck.

This one is definitely more stiff than my small press. And the table was dead-on square to the spindle right out of the box. I did some drilling with a 3/8 in some stainless yesterday, and it went really well. Much easier to put consistent and more significant feed pressure than what I've used before.

--nathan
 
After years of frustration I replaced the chinese chuck on my Craftsman with a jacobs brand "super chuck" it was worth every penny of the $135.00 I paid for it

-Page
 
Yea I'm with "Abrasive", I bought the Grizzly 7944 a few years a go and it has served well with that low speed...think its a step above the other imports but of course I wish I coulda bought a bigger one!
 
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