Morse Taper connection on Drill Press

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Forum topic by richgreer posted 06-26-2012 07:56 PM 1431 views 0 times favorited 10 replies Add to Favorites Watch
View richgreer's profile


4541 posts in 3224 days

06-26-2012 07:56 PM

I was using a large (3”) Forstner bit on my drill press. The bit snagged and the chuck fell out. The Morse Taper did not hold. I jammed it back into place. However, the connection is not as secure as it was. The chuck has fallen out several times since then.

Is there a technique for getting this morse taper to seat securely?

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

10 replies so far

View jmos's profile


869 posts in 2519 days

#1 posted 06-26-2012 08:09 PM

I had a similar incident. I cleaned (degreased) both surfaces as well as I could and then seated the chuck with a sharp mallet blow. Hasn’t fallen out since. Did find some youtube videos on the subject, but no wonderful wisdom.

-- John

View CharlieM1958's profile


16276 posts in 4368 days

#2 posted 06-26-2012 08:10 PM

First, wipe the taper down with mineral spirits. It needs to be completely clean and grease free. Then when you install it, make sure the chuck is all the way open so the jaws are fully retracted, put a block of wood against the chuck, and tap the wood sharply with a rubber mallet a couple of times.

-- Charlie M. "Woodworking - patience = firewood"

View DrDirt's profile


4464 posts in 3892 days

#3 posted 06-26-2012 08:11 PM

I open the chuck fully so that the three “fingers” that stick down to grip the bit are fully retracted, than a good whack or two with a dead-blow mallet takes care of it.

Make sure the taper (male and female parts) are clean – no sawdust or else you will have excessive run-out.

-- “The two most important days in your life are the day you are born and the day you find out why.” Mark Twain

View Chris 's profile


1879 posts in 4140 days

#4 posted 06-26-2012 10:27 PM

A Trick a machinist friend taught me when I had this happen on my Old DP:
1. Clean as Charlie said
2. Open the Jaws fully
3. place in Freezer for a couple of Hours (Metal Contracts)
4. Re-insert as suggested by Charlie.

When the metal heats back to room temp the mating surfaces will fit far tighter. It worked for me….

-- "Everything that is great and inspiring is created by the individual who labors in freedom" -- Albert Einstein

View MonteCristo's profile


2099 posts in 2338 days

#5 posted 06-27-2012 12:13 AM


Thanks for the tip ! I have had exactly the same issue when using big Forstner bits on my drill press as this thread describes. I tried cleaning it well and doing the reinstall as described above but it seemed the big Forstners (4” or so) still caused trouble. Your trick is worth a try.

When I think about this trick more, if the chuck shrinks a bit in the freezer, then gets reinstalled, isn’t it going to expand as it warms up and then not be as tight as otherwise ? Am I missing something here ??

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

View richgreer's profile


4541 posts in 3224 days

#6 posted 06-27-2012 12:23 AM

Thanks to all for your great advise. This is great.

Of course, I knew this was the place to come for great advise.

Thanks again.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View MedicKen's profile


1615 posts in 3611 days

#7 posted 06-27-2012 01:52 AM

Clean as stated above, place chuck back completely open then instead of hitting it with a mallet or hammer use a block of wood and the press itself to press the taper back into place.

-- My job is to give my kids things to discuss with their

View Andywoj's profile


5 posts in 2310 days

#8 posted 06-28-2012 01:25 AM

Good tip on the freezer.

View NormG's profile


6253 posts in 3153 days

#9 posted 06-28-2012 02:01 AM

Sounds like they all would be of benefit, I will keep the freezer tip in mind

-- Norman - I never never make a mistake, I just change the design.

View AHuxley's profile


809 posts in 3471 days

#10 posted 06-28-2012 02:26 AM

@MonteCristo the taper will expand every so slightly when it returns to room temp thus tightning the joint. Imagine a bisquit or dowel that after installation swells the joint is tighter. The only issue I see would be the taper could actually push itself outward as it heats up since it is well a taper.

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