Drill Press Runout

A

AlanF00

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I recently bought a Mario Mark 1 benchtop drill press (perhaps 20 years old, made in Taiwan but no longer, possibly an old Harbor Freight model). It's mostly in good shape, and I'm going through it cleaning up what I can. The original chuck was rusty and felt gritty, so I just bought several sizes of used Jacobs chuck and arbors. Now I'm looking at runout, but I don't know what reasonable tolerances on drill chuck runout are.

I measured the runout on one Jacobs arbor: less than 0.0005" on the 3JT taper. But with a 1/32-1/2" almost new chuck the runout on a test piece of 3/8" drill rod was about 0.007" at the chuck end and about 0.013" four inches from the chuck. Are these reasonable numbers?

Also, I'd like to lubricate the innards of these chucks. Is there a good way to do this without pressing them apart? Can I soak them in a good light oil? I hesitate to disassemble them using a vise and aluminum bar stock.
 
Run out on a drill isn't something I worry about too much. A drill doesn't make precision holes anyway.
The accurate sharpening of a drill bit has a lot more to do with it than a thousandth or two of run out
on a chuck.
 
The newer Jacobs keyed ball bearing taper mount chucks specify a runout of .003" or less at half the chuck capacity.

The plain bearing taper mount and threaded Medium and HD models specify a .004" runout.

The precision keyless models specify .0016" at half capacity.

The light duty chucks have no runout specification.


Although Albrecht claims to have the most accurate chucks in the industry I couldn't find a run out specification in any of their most recent catalogs. One article did mention an .04mm runout, but didn't specify what size or model it was referring to.
 
Just to make sure, check the runout at both ends of the Jacobs arbor taper, not just at one location, and mark both high spots. Then you will have a better map of what the spindle is doing. Any additional runout you find on the drill shank will be due to the chuck or the drill.
 
MrWhoopee said:
It's a drill press, not a mill. Put it in service and move on.
Click to expand...
Agreed! Drills are only capable of bulk removal of metal, and finishing the hole for fussy work needs to be completed with additional operations. It is good to understand that the use of drills is not going to be a high accuracy operation. Still, it is also good to be able to get close to what we predict we are attempting, so we can generate less scrap...
 
AlanF00 said:
I recently bought a Mario Mark 1 benchtop drill press (perhaps 20 years old, made in Taiwan but no longer, possibly an old Harbor Freight model). It's mostly in good shape, and I'm going through it cleaning up what I can. The original chuck was rusty and felt gritty, so I just bought several sizes of used Jacobs chuck and arbors. Now I'm looking at runout, but I don't know what reasonable tolerances on drill chuck runout are.

I measured the runout on one Jacobs arbor: less than 0.0005" on the 3JT taper. But with a 1/32-1/2" almost new chuck the runout on a test piece of 3/8" drill rod was about 0.007" at the chuck end and about 0.013" four inches from the chuck. Are these reasonable numbers?

Also, I'd like to lubricate the innards of these chucks. Is there a good way to do this without pressing them apart? Can I soak them in a good light oil? I hesitate to disassemble them using a vise and aluminum bar stock.
Click to expand...


You bought used chucks to begin with, and they aren't precision chucks when new, so you get what you get.
It seems like you can do one of three things. Buy a used Albrecht, which will be better, rebuild your Jacobs chuck,
which may improve it, or just live with it. I'd drill holes for a while and decide later if you're happy with it.

If you soak it in oil, it will lubricate it, but it's still probably full of crud. An arbor press is a good tool to press them apart,
so now you know what your next tool purchase will be... :)
 
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If you can get the arbor off the chuck, it can be pressed apart pretty easily with a regular bench vise. The small arbor press HF sells also makes life easy. The eBay chucks I get a lot of the time are prettied up on the outside to sell, but the insides are horrible. The last one I got I just threw in a jar of mineral spirits to soak after pressing apart. A light coating of grease with a paint brush is all it needs. You don't really need to regularly disassemble and maintain a chuck if it works, so grease will last a lot longer than oil.

It is true that drill press runout is really not an issue for the intended purpose. 13 thou a few inches from the chuck isn't fantastic, but once the bit finds a center punched or drilled hole, it'll flex a bit to keep center. Even in chuck with zero runout, long jobber length twist drills don't keep amazing positional accuracy unless you start it off with a stiff spotting drill.

My biggest issue with runout is the annoying vibration if the work isn't clamped down well, as is usually the case when woodworking or holding a large chunk of metal. Doesn't really cause any issues, just bugs me.

Somehow the chuck I have with the least runout isn't any of my jacobs super chucks, but a Taiwanese brand called golden goose. I don't have a tenths indicator, but it's less than a thou about 3 inches from the chuck. It's amazing because the inside had enough rust that even the ball bearings and races are terribly pitted, but I use it a ton anyway.
 
Drill Chuck Disassembly.jpg
Drill Chuck Disassembled.2.jpgDrill Chuck Disassembled.1.jpg

Don't know if this any help,this is what my key-less chuck inner parts look like. Chuck was stiff to tighten,
works smoothly after light coat of grease. Make sure you mark position of fingers,I think the body screw
is a left-hand thread.
 
big o said:
Don't know if this any help,this is what my key-less chuck inner parts look like. Chuck was stiff to tighten, works smoothly after light coat of grease. Make sure you mark position of fingers,I think the body screwis a left-hand thread.
Click to expand...

Be careful where you put grease in an Albrecht chuck. Grease the bearings and the seat where they sit. DO NOT allow any grease or oil on the spindle or its thread in the body, and yes, the spindle is a LH thread. A light coat of oil on the jaw guides and inside the hood will improve smoothness but the critical thing is not to get any oil on the spindle threads or the chuck will loosen in use.
 
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