Is this drill chuck out of spec?

[drcrea]

Thanks for the input all! Lot's of great info!

If the product calls for 0.0016 TIR as the spec, then that is what you should directly measure. If they list 0.0016 RUNOUT as the spec, then you should expect up to 0.032 to show up on your indicator.

I rechecked, and the product spec sheet says 0.0016" MAX RUNOUT. So if I understood correctly, I could measure up to 0.0032" in runout and still be within the spec? (assuming that everything else was perfect)

Back up one step for us....is the MT2 integral to the chuck, or is it an arbor pressed into the chuck?

Yes this is a integral chuck. They call it a "solid" where the drill chuck is integrated with the arbor. As a novice I figured this was a better choice as I eliminate one point of error. Are these good or would I have had better luck with a separate arbor / chuck?

One thing to try, minimal measuring, no math... Document your current measurements AND positions. Mark the taper where it is. Knock the chuck out of the spindle, clock it 120 degrees, re-install the chuck in that position, and repeat your measurements. Then do that a second time. Clock it another 120 degrees, and document a third set of measurements.

I don't think I can do this since it's a integral chuck and it has a tab on the top. I can only insert it in one of two positions 0 or 180 degrees. Is there another way to check this?

 

[drcrea]

Just because nobody said it yet; it’s a drill chuck. If it looks to the naked eye like it’s spinning straight, then it’s as precise as it needs to be.

Totally agree! A drill press is not by any means a precision tool. What sent me down this journey was the fact that my old chuck was wobbling so bad that I wasn't able to use a forstner bit anymore. Visually wobbling. Instead of messing around with the cheap chuck the press came with, I decided to upgrade to a keyless and put a little more quality into it. And you know how the story goes...you buy a new chuck which you now what to measure so you get to buy a new dial indicator (jeweled) and a new magnetic stand and ...

 

[Jake M]

I rechecked, and the product spec sheet says 0.0016" MAX RUNOUT. So if I understood correctly, I could measure up to 0.0032" in runout and still be within the spec? (assuming that everything else was perfect)

Yes, that's how that works. The most practical way to measure runout in a rotating thing doubles the actual error. When you measure 0.0032 on your indicator, that puts the actual "off center" at 0.0016 away from the center.

Yes this is a integral chuck. They call it a "solid" where the drill chuck is integrated with the arbor. As a novice I figured this was a better choice as I eliminate one point of error. Are these good or would I have had better luck with a separate arbor / chuck?

It doesn't really matter too much for a drill chuck. The one piece design is one less piece, which is one less source of error, but it also means you can't change the arbor to something different.

I don't think I can do this since it's a integral chuck and it has a tab on the top. I can only insert it in one of two positions 0 or 180 degrees. Is there another way to check this?

You did say that, and it kind of went in and out of my mind before I read through the post and replied. You can still probably should measure the runout on the inside of your machine's taper if you can. You should know what it is. It's the kind of thing that might be useful to know now and then, but most days it might just be splitting hairs that don't need to be split. You're right, you obviously can't clock that taper three ways as I suggested, but you can certainly take the slightly better of the two possibilities.

An overall thought for perspective-
Drill bits are notorious for wandering. Both when starting holes, and in the holes. They're not a precision tool. If you measured 0.006 and some change TIR (Indicator against a rotating end mill shank in the chuck), then that puts you at 0.003 and some trivia off of the spindle centerline. If you drop a drill on a punch mark with that kind of runout, that drill is going to "find" the punch mark whether you want it to or not. What you have now is going to work very well for you. If you want to chase that further (I would, because I'm like that....), you probably could measure "everything" and put the puzzle pieces together, but be aware that you do not "have to". Where you are at will give as good of a result as any given drill bit is capable of.

 

[G-ManBart]

Yes this is a integral chuck. They call it a "solid" where the drill chuck is integrated with the arbor. As a novice I figured this was a better choice as I eliminate one point of error. Are these good or would I have had better luck with a separate arbor / chuck?

Yes, they are better from an accuracy/runout perspective. It does eliminate a point of error and there have seen threads where folks put a lot of time into testing drill chucks for runout and the integral designs are always significantly better.

Personally, I think it matters enough to go with that style. I use proper spotting drills to start holes so when I dial in to spot a hole, I know it's going where I want it. Starting holes with twist drills isn't really a great idea, although the stubby versions aren't too bad about wandering. Using spotting drills and a quality chuck means I can often skip having to punch a spot and still be certain the hole is where I want it.

 

[FOMOGO]

Run it. for a drill chuck that is more than expectable. Mike

 

[mksj]

I have two Llambrich integral R8 chucks, JK-130 R-8 and their 5/8" Hexa HX-16 R-8, both measure with a TIR of around 0.001". I use them for both drilling and milling, the TIR is more important with the latter. They also specify the TIR at some distance like 2 or 3" out, but must have been an older catalog. I would first verify that the problem is not with the spindle or taper causing some skew, so do you see a similar effect say with an ER collet or other type of holder at the same distance out from the spindle. I would not expect a drill press to have the same level of precession as a mill. As others have mentioned, the accuracy of a standard drill is probably worse then what you are measuring. I typically use mechanic or stubby drills in my mill because they are less prone to flex/walking when you start drilling. If I need high accuracy, I use a spotting drill to start the hole. You see the same issue when using a drill in a lathe tailstock.

 

[Forty Niner]

Any imperfection of the surface of the MT that you are installing the chuck into can cause the chuck to not run true. A spec of dirt or a scratch can cause that much runnout out where you are measuring it. Imagine a bit of something in that tapered fit that cocks the tapered adapter. It could show low runnout before the chuck but could show much more out where you are measuring a chucked rod.

 

[FOMOGO]

I have an R8 Llambrich Hexa drill chuck, and it is by far my favorite. The hex key method of tightening far out shines a conventional chuck key, or the uncertainty of a keyless chuck. Picked it up on amazon 7-8 years ago for under $100 new, even back then that was about 25% of the going rate. Mike

I have two Llambrich integral R8 chucks, JK-130 R-8 and their 5/8" Hexa HX-16 R-8, both measure with a TIR of around 0.001".

 

[drcrea]

Update: I bought some precise bar stock, Thompson linear motion shaft 1/2"x6". I measured it on my surface plate and as far as I'm capable of determining the 6"shaft was dead straight and perfectly round at 0.4992. As best as I could measure. I removed the chuck and cleaned the taper and arbor with acetone and a lint free micro-fiber cloth. Using my new precision bar, I still measured 0.006 runout when measured right at the chuck jaws.

I ended up calling the vendor where I purchased the chuck and talked with their tech support. We went over everything I did and what I was seeing and he agreed it seemed a bit excessive and they would send me a new chuck. Apparently Llambrich has an unconditional satisfaction warranty so they just replaced the product. I wasn't even asking for that...wow! I was happy to send it back for warranty repair, but they said that wasn't needed.

New chuck arrives and after installing it I'm measuring 0.003~0.0035. Basically 1/2 of the first chuck. Much better!

 

[Aukai]

Thanks for the follow up.