Drill press bits slipping in chuck

[WillyWeld]

I bought a new Drill press ($300 job from Granger tools) and I keep having trouble with drill bits slipping in the chuck.
Recently I wanted to drill .095 mild steel with a new bit (5/8" bit with a 1/2" smooth shank). I take small incremental steps up in drill bit sizes to get to the final hole. I started with less than 1/4" bit. For the last step I went from 1/2" to 5/8". Some of my medium size bits have shanks with flat sides and they don't slip but all (small and large) of the smooth shank bits slipped to some degree. By slipping, I mean the bit catches on the metal and the chuck keeps turning. I use cutting oil. I try to crank down as hard as possible with the chuck key (should I put an extender on it for more torque?). I have the Machinist Handbook on order so I can better understand drill bit speed, but I thought I run this by you guys.

[Brainfarth]

When I've had that problem, I would tighten the chuck on all three spots where the key fit. If I got desperate enough I would either grind or put the bit in a vise to mar the end up for the chuck to grab on better.

[Sirarcalot]

It has been my experience that all drill presses come with crappy chucks. I would order a new Jacobs chuck with the correct taper to fit your arbor. You may want to take out your arbor and take it into your tool supplier to get the right taper. A good one is about $50 to $60. I did this with a $100 Homier floor standing drill press and it helped turn it into a pretty good tool.

It's common for the wood workers to upgrade their drill presses by changing their chucks since they drill a lot of large holes that tend to put a lot of stress on chucks. Even the more expensive drill presses seem to have low end chucks that slip easily.

[Sirarcalot]

If you want to measure your Jacobs taper instead of removing the arbor, here is a website to show how.

http://www.newmantools.com/tech/taper.htm:D

[stingers]

Willy Weld;

This won't fix your chuck from slipping on smooth drill shanks but you won't have to keep changing drills. The Unibits do have some flats on the shank to lock the chuck jaws on.

Unibit® Step Drill
Drills hole sizes 1/4in. to 3/4in. in 1/16in. increments. Has 1/8in. step thickness and 3/8in. shank. Titanium nitride-coated step drills cut perfectly round holes. Friction-reducing surface runs cooler and self-lubricates while running dry. U.S.A.

They make more sizes than this too. I have one that drills up to 1 inch in dia.. Drilled holes in 1/4 inch steel angles. Cuts great and no egging.

Search for unibit drill and you will find sellers on-line.

[atucker]

I just posted a similar response in another thread - BUT. Dewalt is using a keyless "ratcheting" chuck on their XRP cordless drills. The hammerdrills also use the same type chuck with carbide jaws. I have a DW989 Cordless Hammerdrill with this chuck and I can honestly say I have NEVER had a bit slip in the year I have owned and used it. I've drilled lots of holes in wood, different metals and concrete. I don't know who makes the chuck, it has not identifying marks, but whoever made it got it right - awesome chuck.

Allen T.

[david_r]

I would tighten the chuck on all three spots where the key fit.
Brainfarth is dead on.
Tightening a keyed chuck any other way is just plain wrong.

[Tackweld]

No mystery here..Keyed chucks have 3 key holes to equalize the clamping pressure on the 3 jaws. Try this...use any bit you want and tighten *hard* in 1 hole, I guarentee you'll still get more movement in the other two. I've done this for so long it's automatic now & with large bits I go around twice.

[cutter]

Originally posted by Tackweld
No mystery here..Keyed chucks have 3 key holes to equalize the clamping pressure on the 3 jaws. Try this...use any bit you want and tighten *hard* in 1 hole, I guarentee you'll still get more movement in the other two. I've done this for so long it's automatic now & with large bits I go around twice.

I remember seeing my father do exactly the same thing around 1950 on his homemade drill press. It was built around an old Thor half inch drill which he kept all his working life. That chuck-tightening technique was the first "shop tip" he ever taught me that stuck.

[MACCA]

i find that a tack of weld on the bit shank ground back in order to create a small dimple will ensure that the bit won,t turn in the chuck.

MACCA

[Sirarcalot]

I agree that the best way to tighten a chuck is in all three holes, but a crappy chuck is still a crappy chuck.

[MAC702]

I've been known to take my grinder and turn a bit into a "hex" shank, just by adding three flats. Works great.

PS, anyone know anyone that needs some BIG drill bits that ARE NOT reduced shank? I've got some 1", 15/16", and a few others that are still brand new in the box. One of those package deals I got at a closing business, and never had a need for.

[morpheus]

I bought a decent chuck a few months back, a keyless one at that. Couldn't be happier with my drill press now. it cost me about $30 + shipping from here: http://www.lathemaster.com/Keyless%20Drill%20Chucks.htm

http://www.lathemaster.com/TN_Keyless_58_MT3.jpg

[WillyWeld]

Thanks for all of the great info. Looks like I should try tightening the chuck using all three holes first since its the cheapest and easiest solution. Then work from there.

Stingers, I always wondered about unibit step bits. I certainly like the idea of not changing out bits. What's "egging"?
Anybody else have a preference of "regular" drill bits vs unibit drill bits? Pros & Cons? A quick search on the net showed lots of unibits for "thin metals". Do I need to find more industrial sites to get a unibit for thicker steel?

[stingers]

Willy Weld;

"Stingers, I always wondered about unibit step bits. I certainly like the idea of not changing out bits. What's "egging"?"

When drilling thin metal with a large drill the drill point breaks through the metal and no longer has anything to keep the drill centered on the hole and the drill will wonder or wobble in the hole which results in an egg shaped hole. Or at least not a true round hole.

The Unibits act like a piloted drill bit as the smaller steps keep the drill centered. Where I worked we had tool grinders (people) that could grind pilots on regular drill bits or end mills to use as piloted drills for enlarging holes in thin metal. These were usually holes in parts that were in assemblies that couldn't be sized with a piloted punch.

There are Unibits that are for thicker materials. I have one that will drill through 3/16 thickness. For 1/4 inch I drill part way from one side and then turn the part over and complete the hole. The only thing that you have to be careful about is drilling too deep and making the hole too big with the next step of the drill.

[Sirarcalot]

Thanks Morpheous, that looks like a nice chuck at a good price.
Also, I love unibits. I don't have one now, but I used to use them when I was installing car stereos, working my way through college. This reminds me what I need to pick up next time "she who must be obeyed" lets me go to the tool store.

[MAC702]

Anyone know a good way to sharpen a unibit? I've tried the file technique as described on the package, but it never worked. Two of mine have a dead step. One from someone borrowing it and not noticing the drill was in reverse and just did nothing but get it hot. The other was also borrowed and I have no idea how they killed a step.

[Aaron]

Isn't this a weld forum?

Lay a short bead on the bit, place it between the jaws, and it will not slip.

[enlpck]

MAC: A small diamond burr in a die grinder has worked well for me. The cut happens at the step, so I concentrate on matching the original angles there, and let the rest of each size fall where it may.

[rusted]

Originally posted by morpheus
I bought a decent chuck a few months back, a keyless one at that. Couldn't be happier with my drill press now. it cost me about $30 + shipping from here: http://www.lathemaster.com/Keyless%20Drill%20Chucks.htm

http://www.lathemaster.com/TN_Keyless_58_MT3.jpg

I like that chuck. I'm happy with the chuck in my TSC Clarke drill (chinese), but I could see that speeding up my work a LOT.

I don't have a problem with slipping now. Does that thing really hold a drill even when drilling into like brass? That stuff is 'catchy'.