Jacob's taper chuck keeps falling off of taper.

[jorp_porp]

Ello. I have an old Atlas drill press with a tapered jacobs chuck, and it keeps falling off of the spindle.

I've cleaned both the spindle and the chuck with acetone and a dremel wire wheel, and It gets some solid taps with a rubber mallet to get it on there. Still falls off.

Anyone have any tips? Not sure what else I can do.

 

[Steve from Socal]

Does the chuck spin true or wobble? Sideloading can displace a chuck taper. The other thing is the taper bottoming out before the taper sets? Clean the end of the taper and mark it with dye/ink and see if there is a wear mark. If that is the case, grind the end of the taper a bit to releive the taper length.

 

[rlitman]

...Sideloading can displace a chuck taper...

For those not aware, you shouldn't be using a drill press for milling. This is what happens.

Once the chuck falls out, there's a good chance the morse taper hit something like the table or the floor and raised a burr. Give it a good inspection for burrs and stone off any high spots that shouldn't be there.

 

[imagineer]

The chuck I use on my milling machine had the same problem. I don't know if this was a "good fix", but it's been holding for several years now...

I wrapped the arbor with fine Emory cloth and slipped the chuck over it. Pressing the two together, I twisted the chuck back and forth so to create a roughened surface on the ID.

I then put the chuck arbor on the lathe and polished it using fine Emory cloth. I did this while the arbor was spinning so to make the microscopic scratches perpendicular to the long axis of the arbor.

This made tiny horizontal radial scratches inside the chuck and on the outside of the arbor. After cleaning both with acetone (and letting it dry) I applied a thin coat of blue Loctite to the arbor and pressed the two pieces together. I lightly clamped it together in a bench vise and left it sit overnight.

Like I referenced earlier, I don't know if this was the correct method, but it's held up well.

 

[mreisner]

Consider also that you probably got something 75 years old or older there and the taper may just be worn out. There are reamers for Morse tapers.

 

[Cruzan80]

I've cleaned both the spindle and the chuck with acetone and a dremel wire wheel, and It gets some solid taps with a rubber mallet to get it on there.

My guess is the wire wheel was too aggressive, limiting the amount of surface contact. Hence less "grabbing" force.

 

[jorp_porp]

Does the chuck spin true or wobble? Sideloading can displace a chuck taper. The other thing is the taper bottoming out before the taper sets? Clean the end of the taper and mark it with dye/ink and see if there is a wear mark. If that is the case, grind the end of the taper a bit to releive the taper length.

The spindle has a bit of wobble but it's really only a few thou for run out. That said, I'll measure that again tonight and see if that has changed. The dye is a good idea. I should have some india ink.

 

[jorp_porp]

Consider also that you probably got something 75 years old or older there and the taper may just be worn out. There are reamers for Morse tapers.

Yeah I think its mid to late 30s. I'll have to look in to reamers. Thats a word ive heard thrown around but id be lying if I said I knew what a reamer is lol.

 

[seber]

The wire wheel was almost certainly too aggressive. If it left any marks on the male taper, you are done. Locking tapers must be almost polished to work properly. At this point I would agree that you are going to need a chemical solution.

 

[jorp_porp]

The wire wheel was almost certainly too aggressive. If it left any marks on the male taper, you are done. Locking tapers must be almost polished to work properly. At this point I would agree that you are going to need a chemical solution.

It didn't feel aggressive, it was just one of these guys. Probably should've gone with the nylon brush, I suppose

 

[RTM]

It didn't feel aggressive,

With your 1/2" vs 1 mm issue on another thread, you may not be the best judge of that?

 

[jorp_porp]

With your 1/2" vs 1 mm issue on another thread, you may not be the best judge of that?

I got dropped and my calibration went out of wack

 

[alfadan]

I don't have a lot of experience fixing bad tapers, but I think, practically, it would take quite a bit of abuse for it not to hold. I suspect damage from previous owners.

Use the above suggestions to carefully clean with very fine abrasive to shiney smooth. If the taper is bad, I could see even an uneven drill causing enough side load to knock it loose.

 

[Dagny]

would oil help

 

[jblnut]

I had a chuck that kept falling off and I welded it to the shaft. Problem solved. Worst case is I need to buy another taper adapter. No big deal.

 

[Steve from Socal]

One more thought on the installation. A few taps with a rubber hammer may not be seating the taper. Clean the two parts and reseat with a real hammer 16-24 oz and a piece of hard wood or aluminum between the chuck and shaft. Open the chuck so the jaws are flush or below the chuck body and tap the chuck in place, then give the chuck a couple of good hits. About what you would use on a center punch or drift. A light tap may seat a new taper, and old chuck and shank need a bit more.

 

[rlitman]

It didn't feel aggressive, it was just one of these guys. Probably should've gone with the nylon brush, I suppose

Nah. Those aren't anywhere near enough to damage any size MT. Any fine wire brush is ok. Once you go to the heavier wires, the wire can leave indentations in the surface, and those dimples have raised edges that throw off the geometry. I don't think this is your issue.

As I said. Double check the chuck taper for burrs. Where your wire brush removed any rust isn't the issue. Well, rust left in place would be a problem, but rust removed leaves a crater, and that's NOT a problem.

While you're at it, take a quick look at the socket and see if there are any burrs at the mouth. Ink the taper in layout fluid (or permanent marker), hand fit it and see what's rubbing. That'll give you an idea if there are any raised spots that need to be honed down.

 

[OccupantRJ]

The spindle has a bit of wobble but it's really only a few thou for run out. That said, I'll measure that again tonight and see if that has changed. The dye is a good idea. I should have some india ink.

Black Magic marker works well to find high spots. I have always keep one around each machine tool and layout bench.

 

[m.d.hunter63@hotmail.]

I always do a shrink fit on my drill chicks, male part gets chilled, i.e. in the freezer overnight, female part gets warmed in oven at 180. Put them together, they will lock in place. Word of caution, you may never get them apart once done.

 

[rlitman]

I always do a shrink fit on my drill chicks, male part gets chilled, i.e. in the freezer overnight, female part gets warmed in oven at 180. Put them together, they will lock in place. Word of caution, you may never get them apart once done.

I have used the freezer in my garage for bearing shafts. I'll usually place the bearing on an upturned 60w light bulb for the heat source.

 

[rsanter]

Use bluing or just a far felt tip marker to coat one of the tapers and then put the pieces together.

take them apart and then see where there is a lack of contact.

you may have to do this twice, one time each marking the OD and then ID

 

[merkyworks]

Put lapping compound on the chuck taper, then insert and remove a couple dozen times. Then thoroughly clean compound from the chuck and spindle, double check you cleaned it good.

This should knock down the high spots in your taper so you get even and continuous contact.

 

[jorp_porp]

Thanks y'all. I'll do some work on this today. In between all the other work on all the other things.

 

[jorp_porp]

I think it's in there pretty good now.. my runout has went to ****, though.

 

[m.d.hunter63@hotmail.]

How much run out do you have? Drill chucks are not precision tools.

 

[jorp_porp]

How much run out do you have? Drill chucks are not precision tools.

The last time I checked, before tearing down the spindle / quil to fix a stop collar that had slipped, i was getting around 4 thou.

When I checked earlier today, the needle was jumping wildly, more in the 15-20 thou range. Now that I think about it though, i was running it at a higher speed. That may have been a bit too erratic for the indicator.

 

[Firebrick43]

The op stated (important parts in red)

Ello. I have an old Atlas drill press with a tapered jacobs chuck, and it keeps falling off of the spindle.

I've cleaned both the spindle and the chuck with acetone and a dremel wire wheel, and It gets some solid taps with a rubber mallet to get it on there. Still falls off.

Anyone have any tips? Not sure what else I can do.

So are we talking about the jacobs taper on the arbor into the chuck? Or are we talking about the morse taper into the spindle?

Sure sounds like the jacobs taper on the chuck/arbor, if its falling "off" as opposed to "out"

A jacobs taper drill arbor are cheap and readily available. . And drill chuck runout is just as likely to be wear over the years, without a good chuck arbor to measure and compare to its a **** shoot.

If it is the morse taper a reamer is the most reliable way to fix it, and is still touchy. All most any other method except a spindle grinder will create barrel shaped taper.

Either way a new arbor is needed because the old one will just screw up the internal taper again more than likely.

Red = morse taper Should be 2MT
Blue = Jacobs taper Should be 33JT



Or do you have the collar style spindle on the right?

 

[jorp_porp]

The op stated (important parts in red)

So are we talking about the jacobs taper on the arbor into the chuck? Or are we talking about the morse taper into the spindle?

Sure sounds like the jacobs taper on the chuck/arbor, if its falling "off" as opposed to "out"

A jacobs taper drill arbor are cheap and readily available. . And drill chuck runout is just as likely to be wear over the years, without a good chuck arbor to measure and compare to its a **** shoot.

If it is the morse taper a reamer is the most reliable way to fix it, and is still touchy. All most any other method except a spindle grinder will create barrel shaped taper.

Either way a new arbor is needed because the old one will just screw up the internal taper again more than likely.

Red = morse taper Should be 2MT
Blue = Jacobs taper Should be 33JT



Or do you have the collar style spindle on the right?

Collar style on the right, and yeah it was the chuck falling off of the arbor.

 

[Firebrick43]

Collar style on the right, and yeah it was the chuck falling off of the arbor.

I assume the release nut is run up all the way?

Can you take a picture of the 33 jacobs taper on the end of the spindle? How about run out in two places on that taper as well (not something held in the chuck)