Worth it to Get Collets for Drilling?

[SteveHGraham]

I hate putting a drill chuck on my mill. I have to lower the mill four inches to get clearance, and that means I have to move my arm 40 times, which is just way more work than I feel like doing.

Today I was drilling something with a center drill, and I realized it was about the same size as a collet, so I used the collet instead of a chuck.

Now I feel stupid for relying on my chuck so much.

Is it worth it to get a big set of collets for this purpose, or would I have to buy a million of them to get a decent fit on a useful range of bits? I don't really know what kind of range a given collet has.

[John Evans]

Forget it!! You would need collets by 64s for fractional drills and that leaves out in the cold for letters and numbers. Buy a power knee feed ,you will love it . Besides I'm not sure they make 64th collets in R-8. I do on ocasion usea 1/2 collet for drill holding when I'm using my S&D reduced shank drills.

[SteveM]

Put your drill chuck on a straight shank arbor, the largest one you can get that you have a collet for. Then cut off all of the shank except the part that the collet grabs. You will be able to change out the chuck with less clearance than having it on an R8 shank.

You could standardize all you tooling to one size of straight shank. Then you can leave in one collet and swap between fly cutters, boring bars and drill chucks.

(not my idea, got it from Harold)

Steve

[Harold_V]

You could standardize all you tooling to one size of straight shank. Then you can leave in one collet and swap between fly cutters, boring bars and drill chucks.

(not my idea, got it from Harold)

Steve

I ran (built) a lot of customer tooling when I operated my shop. I had to change tools often, so that's precisely how I operated. I'd use a 3/4" HSS end mill for roughing, switch to a 3/4" shank fly cutter for finishing, then change to a 3/4" short shank Albrecht chuck, just as Steve described. Fast and easy.

Worked for me.

Harold

[SteveHGraham]

I can see that the R8 shank I bought was a mistake.

[seal killer]

Steve--

I use collets to hold drill bits instead of the drill chuck every chance I get. They hold far better than a chuck.

--Bill

[Harold_V]

Yep, what Bill said. But there's a couple negatives, one of which is just that using collets is quite slow, especially if you center drill then double drill.

And that leads to the next issue. Unfortunately, collets for mill spindles aren't made in a broad selection of sizes.

Yeah, I know---the ER series is reputed to be able to span all sizes---but that can get expensive, as they do that by flexing beyond reason. They'll do it a few times, maybe even lots of times, but that comes at a price. It's not a question of will they break, but when. They will break because they're being called upon to flex beyond reason.

My personal advice is don't use such collets beyond a couple thou of nominal in either direction. Doesn't leave you with many options, aside from using a drill chuck. If you have a good one, it will by quite reliable, and if you find you must make several changes (center drill, drill, drill again, countersink, etc.), you would be very well served by using a Wahlstrom quick change chuck, which allows for changing tools without stopping the spindle.

Yeah, I practice what I preach, if you're wondering.

Harold

[Frank Ford]

One of the best tools I ever bought was a Kurt power drawbar for my Bridgeport clone. Not only does it serve my first intended purpose of avoiding a step stool or other platform to reach up there, but it's really quick and easy to change collets or other R8 tooling. I routinely switch from mill to drill to countersink to tap or whatever using collets to avoid moving the knee to clear drill chucks.

I have the full set of 1/32" increment ones, and metrics as well. I use the odd ones surprisingly often. Hardinge makes them in 1/64" increments, so maybe, someday. . .

[Richard_W]

Yeah, I know---the ER series is reputed to be able to span all sizes---but that can get expensive, as they do that by flexing beyond reason. They'll do it a few times, maybe even lots of times, but that comes at a price. It's not a question of will they break, but when. They will break because they're being called upon to flex beyond reason.

Harold

That hasn't been my experience with ER collets. They have a range written on them and as long as you stay with in that range you shouldn't have any problems. We haven't had any ER collet failures that I am aware of other than they don't survive crashes on the CNC very well.

Richard W.

[Harold_V]

Thanks for your input, Richard. I have based my opinion on experiences I had with similar collets, but many years ago. I'm comforted to hear you've had acceptable results, as there are times when I've had to use my ER32 collets beyond nominal, which I've done only with considerable concern. I might just look at things a little differently now.

Harold

[RCW]

Forget it!! You would need collets by 64s for fractional drills and that leaves out in the cold for letters and numbers. Buy a power knee feed ,you will love it . Besides I'm not sure they make 64th collets in R-8. I do on ocasion usea 1/2 collet for drill holding when I'm using my S&D reduced shank drills.

John:

Where does one find a power knee feed?

Bob

[John Evans]

John:

Where does one find a power knee feed?

Bob

Everybody from Shars to Servo . From low $300s up. I have them on both of my BPs. Saves on your back and alows power feed drilling . Asong is one brand ,have that on one of my mills.