Drill Press problem

[softailgarage]

My '42 Craftsman Drill Press chuck keeps falling out. Reading some earlier GJ post's regarding this problem, the fix seems to be carefully pressing the chuck back onto the quill, which I do. However, it's only good for a short period of time. Question #1: Is this common (for the chuck to keep dropping)? Question #2: Is there a fix or do I have to replace the quill & chuck?

 

[zkling]

Ouch. That sir is one spun taper. Luckly for you that press is designed for a locking collar drill chuck. Looks like someone in the past has made their own locaking collar and just put a standard drill chuck in it's place.

Wipe the spindle off with an acetone rag then see how bad it is scored. It may be gone.

 

[DocsMachine]

Unfortunately yes, you may have to replace both chuck and spindle.

They mate together with what's called a "self locking" taper- just enough angle to wedge themselves together. The "lock", however, relies on two clean, smooth mating faces, that also have to be damn near the exact same angle.

Any burr, ding, dirt or ridge can keep it from locking- and it's clear as day that both the spindle nose and the chuck recess are badly scarred.

If you can't find another spindle, it might be possible to have a competent machinist regrind the taper. I'd have to see it in person and measure to be able to say definitively yes or no.

The chuck is an easy replacement, grab a Jacobs of the appropriate size and matching taper, and once the spindle's fixed, whack 'er in place.

Actually, best route would be to buy the chuck (assuming the spindle has the meat for a regrind) and then use the chuck itself as a "master" to get the taper just exactly right.

Doc.

 

[tjsr19]

High temp lock tight

 

[Davefr]

High temp lock tight

On a Jacobs taper???

No way!!!

 

[A_Pmech]

The chuck is coming off the taper because the taper is damaged. Self-holding machine tapers work by friction and when the mating surfaces are damaged insufficient friction develops between the two parts.

You can repair the taper by stoning the burrs on the male half while the machine is running. Stone out the female taper of the chuck as well, then finesse the spindle taper until the two print well with prussian blue.

Then, fit the chuck back onto the spindle taper by either hitting it with a lead, brass or aluminum mallet or pressing the chuck firmly into the table with the quill. In either case, retract the jaws fully into the chuck body to prevent damage to the jaw teeth and ring gear.

 

[WhoWhatNow]

The chuck is coming off the taper because the taper is damaged. Self-holding machine tapers work by friction and when the mating surfaces are damaged insufficient friction develops between the two parts.

You can repair the taper by stoning the burrs on the male half while the machine is running. Stone out the female taper of the chuck as well, then finesse the spindle taper until the two print well with prussian blue.

Then, fit the chuck back onto the spindle taper by either hitting it with a lead, brass or aluminum mallet or pressing the chuck firmly into the table with the quill. In either case, retract the jaws fully into the chuck body to prevent damage to the jaw teeth and ring gear.

What do you use to stone the tapers? I am having the same problem with my press.

 

[Givl Reggin]

Is there a fix or do I have to replace the quill & chuck?

Try this method...
http://garagejournal.com/forum/showpost.php?p=2860818&postcount=12

 

[tjsr19]

On a Jacobs taper???

No way!!!

 

[Outlawmws]

What do you use to stone the tapers? I am having the same problem with my press.

An unworn sharpening stone. You need a flat surface. (And keep it moving so you don't wear a trough in to the stone)

 

[A_Pmech]

What do you use to stone the tapers? I am having the same problem with my press.

An india stone of about 220 grit will do the trick. Use a smooth cut file to lightly knock down the burrs before stoning.

Beware that the spindle taper must intimately fit the chuck taper for friction to do it's job. That means it's advisable to print the tapers with blue regularly as you work in the two tapers.

As long as relatively small amounts of metal are removed the operation won't substantially alter axial runout.

 

[WhoWhatNow]

Thanks, I get a stone and give it a try.

 

[softailgarage]

Try this method...
http://garagejournal.com/forum/showpost.php?p=2860818&postcount=12

I'll give this a shot. If this doesn't workj, I'll replace it with one I took off a later Craftsman DP that got scrapped. Can somebody explain "stone the taper" a little more clearly?