Drill Press Runout - Don’t get it…

[mculik5]

I just purchased a Clausing 16VC from the 1960s. It had an older Jacobs chuck in rough shape, so I bought a new keyless chuck, Jacobs model JK-130-J33.

The arbor is JT33.

I removed the old chuck and installed the new one but could see significant runout.

Measured runout about 1” down a 1/2” drill rod is 0.0215.

The runout at about the same spot down the drill rod on the old chuck is 0.012.

I confirmed the drill rod is consistent diameter and straight.

Putting two indicators on the arbor, I measured the runout at 0.0015, as shown in this video -

.

I also ran the quill up/down with a test indicator mounted and found about 0.0065 difference from top to bottom over about 4” with the new chuck. Same measurement was about 0.003 with the old chuck.

Any ideas? Is 0.0015 runout acceptable at the arbor? Could the rest be coming from the chuck or install method?

Thanks.

 

[michiganbuck]

Drill press and chucks often have noticable run out .021 is a little high but not uncommon.
You might put a straight rod in you chuck and try to find the best place to put in your chuck.
Accurate holes are made with a scribe line and a punch, about .003 to .oo7 with having good scribing talents. or transfering a hole with a transfer punch. for close a cennter starte in a punch better that a normal drill.
Sometime cleaning out the machine taper for nicks or dirty helps..
Some times a spindle is bent. A blue-up checks the taper to match.
Q: Is 0.0015 runout acceptable at the arbor? I think thatbis pretty darn good.

In Todays craze world I would nort rule out buying a counterfet drill chuck

 

[L Vanice]

The large male thread above the 33 JT is for a locking collar that also acts to safely eject the drill chuck or other spindle tooling. Back in the 1960's, this type spindle was used with several accessories: drill chuck, Morse taper adapter, buffing wheel arbor and collet chuck. The safely removing feature was very nice because it is quite difficult to remove 33 JT chucks that do not have the locking collar. Removing a chuck by other means can bend the spindle. I think you can still buy a new Jacobs chuck with the collar, but it may be Chinese and of doubtful quality.

Here is a picture of a Rohm brand 1/2" chuck with 33JT with collar I used to have. That is a Rockwell drill spindle in the picture, but Craftsman also used that 33C taper. Rockwell let you order the machine with either the 33C taper or a 2 MT spindle, also in the picture.

Larry

 

[john.k]

My old Asquith radial arm drill had a #5 taper spindle ,yet it was bent somewhat..........it also had a quick change collet setup that was actually quite free aligning ,and holes were centred by the drill point.,so the slight bend didnt really matter.

 

[Laverda]

If you bought a new Jacobs chuck, it was made in China and is nowhere as well made as the old versions which no longer exist new. And yet they still charge the same price. The same chuck made in the same factory in China without the Jacobs name on it would have cost you 1/4 the price. They are not horrible chucks but not as nice as they used to be.

Before all Jacobs manufacturing went to China, the precision key-less chuck they sold was made by Llambrich in Spain. You can still buy Llambrich new but they are not cheap.

 

[eKretz]

.0015" runout at the arbor is acceptable for a drill press. Next question is whether the arbor is bent. Should be placing both indicators in line with each other but one at the top of the taper and one at the bottom. Then give it a revolution and record at 90° intervals and make sure they match pretty closely.

If that looks good, you could have a defective chuck or you could have not mounted it well. You could also potentially have a male or female taper (or both) with non-straight sides, which will allow the chuck to pivot to some arbitrary angle during mounting, causing excessive runout, worse the farther you check from the base of the chuck.

 

[michiganbuck]

A reamer with the correct taper can be an ok machin taper gauge. You can plate check it and then use it for a ok gauge. Buying one that likely you might use is good.

 

[neanderthal mach]

Checking the run out is of course worth while, but are there any burrs and/or debris on or in the male & female tapers? Then blue up the male taper and check the pattern for fit to that chucks female taper. On an integral taper like your drill press has, I run the table up, both tapers need to be clean and dry, retract the chuck jaws within the chuck so only the chucks face is visible, don't use the jaws to push against. Then use the quill down feed and with only a couple of lbs on that quill handle push that chuck face against a piece of wood laying on the table to just start the chuck onto the male taper, then rotate the chuck 90 degrees, add a few more lbs and repeat going around the chuck. Maybe 50-80 lbs on the quill handle should fully seat the chuck if both tapers do properly match.

As Laverda mentioned, any new Jacobs chucks will be built in China, there's quite a few older posts here without much good to say about any of those Jacobs chucks since they moved offshore, vastly lowered the quality and kept the same prices the much better American built chucks had. Surprisingly I once had a floor model Crapsman DP with a no name OEM keyed chuck that held anything I ever checked to about .0015" run out. Even my Albrecht chucks aren't a whole lot better than that. I suspect that was just random luck and certainly not something to ever be expected.

 

[boslab]

I bought a Chuck, runout, popped it off rotated it 90 degrees, improved, repeating different spots eventually I got it fairly close, yes it was a cheap thing not a allbrecht so I guess wonkey comes with the territory.
Mark

 

[mculik5]

Thanks, everybody.

I took some more measurements and I'm even more confused...

I put the test indicator and digital dial indicator from the video in line vertically, like @eKretz suggested. They were within 0.001" of each other (possibly a bit less than that, but hard to tell with the digital indicator).

Then I put the test indicator on my mill arbor, where the runout was ~0.0007". The mill has an offshore chuck called Chum Power. Chucking the drill rod in that, I measured 0.0035" runout about 1" down from the chuck. This confirmed that chuck and the rod are good to ~0.003".

Putting that chuck on my arbor, runout at the same spot (about 1" down the drill rod) was even worse, at 0.024".

So, it seems that all the runout is coming from the arbor. But, why am I not seeing that on the indicators?

Thanks.

 

[GregSY]

Back in the early days of Asian tools, I bought a $39 bench top drill press at one of those tools sales they used to have....they'd blow into town with an 18 wheeler and set up shop in the VFD hall for a weekend. I am pretty sure it was made in Taiwan, not China.

In any case, it had a 0-3/8" capacity hand chuck, and it would spin up to 3 or 4 thousand RPM belted for max speed. And you could look at that spindle and chuck with your eyes and it looked dead-ass true. I never measured it but it had essentially no runout....other than the noise of the motor, it looked like it was turned off. I wound up having it liberated by a friend who wanted it for some precision work he did a lot using .032" drill bits.

 

[Superbowl]

Thanks, everybody.

I took some more measurements and I'm even more confused...

I put the test indicator and digital dial indicator from the video in line vertically, like @eKretz suggested. They were within 0.001" of each other (possibly a bit less than that, but hard to tell with the digital indicator).

Then I put the test indicator on my mill arbor, where the runout was ~0.0007". The mill has an offshore chuck called Chum Power. Chucking the drill rod in that, I measured 0.0035" runout about 1" down from the chuck. This confirmed that chuck and the rod are good to ~0.003".

Putting that chuck on my arbor, runout at the same spot (about 1" down the drill rod) was even worse, at 0.024".

So, it seems that all the runout is coming from the arbor. But, why am I not seeing that on the indicators?

Thanks.

Take out the chuck and indicate on the inside of the arbor.

 

[mculik5]

@Superbowl - Thanks. What do you mean? The spindle is one piece - splined up top and smooth through the quill, ending with a JT33 taper at the bottom. If you look at page 7 of this PDF - https://makerspace.tulane.edu/images/2/24/Clausing_15_in_drill_press_model_1672.pdf - the part I'm referring to is 1620-11. There is no inside the arbor.

When I mention above about indicating the arbor, I'm referring to putting indicators against the JT33 taper.

 

[eKretz]

When the chuck and arbor are *loosely* mated is there any wobble? A bluing check is a good next step. Also second the recommendations to check for any burrs.

 

[mculik5]

No wobble when loosely mated. Prussian Blue is on its way.

When I inspected the arbor after removing the old chuck (which took a fair bit of doing), there was some galling and hardened gunk at the spot where the top of the old chuck sat. I tried to Scotch Brite it with the drill press motor running. Didn't work, so I took some very fine sandpaper (probably 1000 grit or so) and cleaned things up. There is still visible galling, but it's towards the inside of the arbor, not like a burr that would cock the chuck.

Thanks for all the help!

 

[dian]

use a sharpie.

one thou difference on the vertical indicators? you mean they are inconsistent by that much? this would be very weird and greatly multiplied further down. you really need two test indicators on there.

im not familiar with that taper, but do extentions/addapters like for mk exist? that would be a good way to see whats happening.

 

[L Vanice]

use a sharpie.

one thou difference on the vertical indicators? you mean they are inconsistent by that much? this would be very weird and greatly multiplied further down. you really need two test indicators on there.

im not familiar with that taper, but do extentions/addapters like for mk exist? that would be a good way to see whats happening.

The Jacobs tapers were designed for mounting Jacobs drill chucks, but became a US and world standard. I have never seen a JT reamer for sale and there are no extensions. You can get chuck arbors with male JT and straight or tapered shanks to fit about any sort of machine.

In Europe and other places, there is an alternate DIN 238 chuck mounting taper with designations starting with B, like B10 etc.

Drill Chuck Taper Dimensions

The drill chuck taper dimensions here will help you identify the correct arbor for your drill chuck.

www.arceurotrade.co.uk

Larry

 

[eKretz]

No wobble when loosely mated. Prussian Blue is on its way.

When I inspected the arbor after removing the old chuck (which took a fair bit of doing), there was some galling and hardened gunk at the spot where the top of the old chuck sat. I tried to Scotch Brite it with the drill press motor running. Didn't work, so I took some very fine sandpaper (probably 1000 grit or so) and cleaned things up. There is still visible galling, but it's towards the inside of the arbor, not like a burr that would cock the chuck.

Thanks for all the help!

Hopefully you were very minimal with the abrasive. That could cause a "barrel" in the shape of the taper, which could cause the inconsistent seating I mentioned earlier. If there are no burrs present, wait and see what the bluing says. May just be a bad chuck.

 

[dkmc]

30 years ago a buddy bought an old 1950's craftsman drill press used. Then he spent the next 2 months obsessing over it including having the spindle taper re-ground to assure near zero run out at the chuck. It's a drill press......not a jig borer.....or even a Bridgeport that could offer a more precise platform. Hobbies are good tho...

 

[eKretz]

30 years ago a buddy bought an old 1950's craftsman drill press used. Then he spent the next 2 months obsessing over it including having the spindle taper re-ground to assure near zero run out at the chuck. It's a drill press......not a jig borer.....or even a Bridgeport that could offer a more precise platform. Hobbies are good tho...

Your point is somewhat valid, but .020"+ is pretty excessive. I wouldn't be happy with that on my drill press.