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Discussion Starter · #1 ·
Craftsman 137.219001 10” Drill Press (2/3 HP)

While I was trying to drill oak using a 1 3/8” Forstner about 1 3/4” deep at 3100 RPM, the spindle / quill fell off. After I got over my surprise I figured out that if I was going to abuse such a big bit, I should have been using a much lower speed. At least I was trying to take small bites to keep the bit temp lower.

Anyway, Now I want to reinstall thespindle assembly. I can’t tell what holds it in place. I don’t see a coupling. It looks like the spindle cavity is just slip fit on the shaft with no key or now shoulder. It seems like all I need to do is push the part back into place and put a wood block under the spindle and use the handcrank to snug it down.

Does this sound right?
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It fell off the taper. Probably from the weight and size of the bit. Remove the bit. Clean both surfaces of the taper. Check for any raised metal if it spun. Remove as needed. Rotate the chuck jaws until they are inside the chuck. Tap it on with a dead blow hammer.
 

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this is a common problem. the chuck is called a Jacobs taper.
it has been used on Delta, Delta/Milwaukee, Delta/Rockwell, Walker-Turner, Buffalo, Jet, Wilton, Atlas, craftsman all have used the Jacobs taper quite successfully for decades. They may have a JT engraved onto them.

vibration will cause them to come loose. both sides of the taper (inside and outside of taper) need to be very clean oil free. push up in place by hand bump it with your hand, it should hold then use a brass or hard wood mallet to drive back on. do not a metal hammer.

Usually One impact from Mallet is enough to hold it. do not beat on it.
 

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Discussion Starter · #4 ·
It fell off the taper. Probably from the weight and size of the bit. Remove the bit. Clean both surfaces of the taper. Check for any raised metal if it spun. Remove as needed. Rotate the chuck jaws until they are inside the chuck. Tap it on with a dead blow hammer.
Thank you for quick reply. This is pretty much what I thought. It just seems too easy.
 

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Discussion Starter · #5 ·
this is a common problem. the chuck is called a Jacobs taper.
it has been used on Delta, Delta/Milwaukee, Delta/Rockwell, Walker-Turner, Buffalo, Jet, Wilton, Atlas, craftsman all have used the Jacobs taper quite successfully for decades. They may have a JT engraved onto them.

vibration will cause them to come loose. both sides of the taper (inside and outside of taper) need to be very clean oil free. push up in place by hand bump it with your hand, it should hold then use a brass or hard wood mallet to drive back on. do not a metal hammer.

Usually One impact from Mallet is enough to hold it. do not beat on it.
Thanks for the explanation. For once, a simple solution!!
 

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From my machine setup days.... As mentioned the tapers must be very clean and bur free. A red/maroon scotch brite pad can be used to clean them up. Final clean with acetone or lacquer thinner so completely oil free and bvack in place with a light tap from a hammer to seat.

On the industrial side, we had Morse tapers. Several sizes some up to 8 inches long with a tang used to knock them out. Pictured is an adapter sleeve so yo get the idea how it is constructed.

429594


Ken
 

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Agreed, a light tap and (assuming the tapers are in good shape) and a team of mules couldn't pull it off.
What no one has mentioned is 3100 RPMs is WAY TO FAST for that bit. I would turn it down to the slowest setting and it would probably still be faster than needed
 

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Discussion Starter · #10 ·
From my machine setup days.... As mentioned the tapers must be very clean and bur free. A red/maroon scotch brite pad can be used to clean them up. Final clean with acetone or lacquer thinner so completely oil free and bvack in place with a light tap from a hammer to seat.

On the industrial side, we had Morse tapers. Several sizes some up to 8 inches long with a tang used to knock them out. Pictured is an adapter sleeve so yo get the idea how it is constructed.

View attachment 429594

Ken
I’ve learned something. I had no idea a tapered fit with metal to metal contact was the strong without a key. I understand the mechanical advantage of a wedge but didn’t appreciate the magnitude.
 

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Discussion Starter · #12 ·
Agreed, a light tap and (assuming the tapers are in good shape) and a team of mules couldn't pull it off.
What no one has mentioned is 3100 RPMs is WAY TO FAST for that bit. I would turn it down to the slowest setting and it would probably still be faster than needed
Yes. You are absolutely correct. I tried to use a little sarcasm in the OP to hide my embarrassment. I understand the importance of drill bit speed when working with metal. I had assumed that for the majority of wood working that high speed was “good enough”. Boy, was I wrong! Once I cleaned up the parts and reattached the spindle, I adjusted my pulleys to the lowest speed and tried again. Would you believe it that the Forstner bit doesn’t have to smoke? Amazing. I learned a few lessons on this one. Thank you for the reminder, though. If I had missed that lesson then I was doomed to continue to abuse my tools.
 

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in my poor editing I missed this ( I.'m not sure what you mean by "for once"? ) should have been Just once [ post #6 ] :confused:

Hardwood and softwood drill speed chart

Here is a chart drill bit speeds that I have used myself in the past.

Also in that chart Forstner bits recommended for hardwood as in your picture showed look like that's a bit speed should have not been greater than 500 RPM for softwood a max of1000 RPM.

my guess the vibration should have been fairly severe and after you reassemble you may want to look for other bolts that may rattled loose in the process. harmonic vibration can dismantle almost anything. :)
 

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Discussion Starter · #14 ·
in my poor editing I missed this ( I.'m not sure what you mean by "for once"? ) should have been Just once [ post #6 ] :confused:

Hardwood and softwood drill speed chart

Here is a chart drill bit speeds that I have used myself in the past.

Also in that chart Forstner bits recommended for hardwood as in your picture showed look like that's a bit speed should have not been greater than 500 RPM for softwood a max of1000 RPM.

my guess the vibration should have been fairly severe and after you reassemble you may want to look for other bolts that may rattled loose in the process. harmonic vibration can dismantle almost anything. :)
Thank you for the chart. While I was abusing my drill press and removing the annealed edge on the bit, there was surprisingly little vibration. The drill press was stalling and the piece was smoking. Good idea to check for loose parts, though.
 

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Machinists would hit it with a lead hammer....and what woodworker has one.
First spin your chuck so the jaws are below flush of the body. (don't be beating on your jaws)
I use a piece of wood against the chuck then smack it good with a steel hammer.
Deadblow hammers I've not had good results seating chucks.
 
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