Drill Press Chuck Runout

[sean69]

You might try taper shank drills for the holes that require more accuracy.

Although that is a fairly deep hole your drilling.

How off line does it go ?


Stu

Hum .... interesting thought! It's a specialized operation, I wouldn't mind spending $$ on a bit specialized for that.... certainly takes the runout out of the equation. The trick would be finding one long enough to get at least half way through my material - I generally have to advance the drill bit in the chuck a bit with what I am doing now.

As far as how far off they go - it all depends on how meticulous I am with setup. generally not more than 3/16" over 10"/12' the real problems show up when the holes are out both vertically and horizontally.

those holes are nothing for 'deep' either ... drilling ramrod holes is the real tricky bit. I regularly have to make drill bit extensions 4' long and purpose made D reamers for the entry holes.... a giant pain!

 

[sean69]

Sometimes a picture is worth a thousand words. Here's an illustration I drew up in Fusion 360 of a two inch wide block 14 inches long. The bottom right edge is skewed off the horizontal by 0.002" which you would see as 0.002" dial indicator error per side if your arch from center in your drill press spindle was 2 inches (4 inch total swinging diameter).

As you can see, the center line of a vertical line (which would be your spindle) starts at 1" at top but over the 14 inches moves 0.014" (almost a 1/64") off from it's original entry (the two dimensions in ( ).

This demonstrates only a error of 0.002 per side so if your table is off more than this it obviously gets worse. Also, errors like this magnify with the length of the piece, so 14" can show a lot of error where you wouldn't really notice it on a very short piece.

If you drill press table is not trammed in very closely on these long pieces you are going to see this error, just as you would on a milling machine.

Maybe I'm barking up the wrong tree, but this is something that gets overlooked sometimes...

Hope this makes sense,
Ted

Make perfect sense & thanks for taking the time to draw up the illustration

For the deep holes my press does not have the overhead room to mount the work and the tool - the table has to be turned 90^ parallel to the tool - I posted a pic in another response. That makes using an indicator pretty much impossible. The laser is a bore sighting laser and is very accurate. setup for it is pretty easy- chuck it, turn on the press, if the dot 'wobbles' on the floor then it isn't straight - repeat until the laser is a dot that does not move on the floor while the press is running. then set the table/fixture so the laser line runs all the way along the fixture and doesn't taper off (like the one image I posted)

That's the best I have been able to figure out.

 

[sean69]

Assuming that you can separate the chuck from the arbour, you can then indicate the arbour for runout. Likely the issue is with the chuck, replacing to a better quality will help.

Deep hole drilling is always a problem, wood or metal makes no difference. There are special drills with a grind for deep holes. Wood with its differing hardness especially in end grain is a problem. I would drill a smaller hole about an inch and follow with the either finish drill or just under would be better. Repeat until done. 1 inch at the time, using the previous hole as a bushing to help guide the drill straighter. Use the finish drill to clean out the hole. Best I can suggest at the moment.

Gun drills and D bits - yes, I have used them, had to make them, they are slow but work brilliantly.

Problem here with my deep holes is that I am working with wildly figured materials, burls, boles etc. the hardness of the material can vary wildly as can the direction of the grain. Drilling a smaller hole first is usually futile because of that

I took a peek at the chuck & don't see an easy way to get it apart. If I replace it (looking like I will) I'll probably replace the arbour at the same time.

 

[sean69]

Sean69, my suggestion re the question of what gives with the chuck is to take it apart and see. I would expect that it could use a bit of deburring and cleaning. Once you have done that it will be clearer whether the chuck can meet your precision requirement.
As mentioned above, common drill chucks are not considered good for precision work. To get the best results from any drill chuck you need to have the best drill bit for the job. I would even say that the drill bit might be more important than the chuck for quality work. You might not have exhausted all your drilling options yet.

Drill bits are something I learned quite a while ago to not cheap out on. Canadian Tire is not here you want to buy precision tooling

Brad points for end grain ... you can't sharpen them so you gotta live with their limited lifetime, but even a beefy 5/8" twist drill can wander in an obstinate piece of walnut.

 

[BaronJ]

Hi Guys,

The drill itself, how its sharpened can make a big difference to how straight a hole can be.
I used to have to drill a 5/32" inch hole in aluminum 6" inches long to land within a 1/64".
Dormer made me the drills to do this job, and they cost a fortune but they worked.
The grind on the cutting edges and the flute form made the difference, between a hole drilled with a normal long series drill and the ones that Dormer made for me.

 

[sean69]

So, do you need a new chuck? Dunno', maybe. If your chuck is the OEM chuck that came with that drill press then I would say dump it and use an Albrecht, Rohm or Jacobs Super Chuck. The OEM Chinese chucks are worthless other than for drilling holes in wood, in my opinion. I would also dump that OEM arbor and get a decent one from Albrecht, Jacobs, Rohm or some other reputable maker.

It's looking like I am leaning towards replacing the chuck, though can't come even close to affording an Albrecht - $400+? ouch!
Though ~ speaking of Asian machines - I am also considering (strongly) upgrading to a larger more rigid floor model.

The biggest issues when we get out of round holes are chatter and vibration. This has little to do with the drill press directly; it has more to do with the drills and how we use them. About 3-4 years ago, I looked into this subject and am "speaking" off the top of my head about what I recall but chatter is a really big deal. As you might expect, speeds have a lot to do with chatter. If you drill a partial depth hole and you see a sunray pattern, like spokes on a wheel, at the bottom of the hole instead of a smooth surface then you have chatter. Just like on a lathe, the solution is to reduce speed and increase feed. It may surprise you to find that this works rather well, crude as it may seem. This is why I tend to run my drills slower and feed harder nowadays and it works.

Yes - speeds & feeds are just as important working with wood as they are with metal - even more so since if you cut too fast your work can actually catch fire!
That's another reason I am considering a new press - something with a variable speed/gear head where I don't have to futz with belts & can dial in my speed more accurately.

The other issue is vibration. As I recall, you can modify your tool web to be thicker and use less relief behind the cutting edge. I may be wrong on this but increasing the contact area at the cutting tip dampens vibration, leading to less out of roundness.

I have never modified a bit either - nor can you with a brad point (though these lee valley ones do have some relief behind the brad points - they really are very nice, but of course useless for metal)

It sounds like you're a gun guy and I'm not sure which brand of reamer works best for your needs. For my simple needs, I prefer Alvord Polk, L&I and PTD reamers.

Well guns are not the only thing that gets built in the shop - but ~mostly~
Honestly, reaming is not an operation I have to do a lot of, I have not had to do any chamber reaming (super specialized tooling = $$$) mostly hand reaming wood. the other bit would be the ram rod pipes (that I ruined) these are generally rough brass castings that need to be opened up slightly to allow the ram rod to clear them smoothly. (3/8 hole, 3/8 rod ... you know) they have a large tab on them (to secure to the stock) so defy being held in the lathe accurately....

 

[sean69]

Hi Guys,

The drill itself, how its sharpened can make a big difference to how straight a hole can be.
I used to have to drill a 5/32" inch hole in aluminum 6" inches long to land within a 1/64".
Dormer made me the drills to do this job, and they cost a fortune but they worked.
The grind on the cutting edges and the flute form made the difference, between a hole drilled with a normal long series drill and the ones that Dormer made for me.

Agreed.
The correct tool geometry for the material... technically for my application into the end grain, a forstner type bit would be ideal, but they just don't make em that long

 

[Tozguy]

I have a 1980s Busy Bee 18" benchtop drill press, got it at auction for $150 a few years ago. It looks brand new, seldom or very lightly used.

But: I had always had trouble drilling straight holes (usually 11"-14" deep) so I finally got around to checking it for runout.

Turns out the spindle is good, solid, no play and +/- 0.0005 runout... as is the chuck shank (arbour?) about the same runout. measuring a ground shaft in the chuck itself, I get +/- 0.0050 runout (!)
Checked the jaws, no dirt looking clean and clear. so:

Is there a way to correct the existing chuck or am I looking at a new chuck?

-thanks
-sean

Gun drills and D bits - yes, I have used them, had to make them, they are slow but work brilliantly.

Problem here with my deep holes is that I am working with wildly figured materials, burls, boles etc. the hardness of the material can vary wildly as can the direction of the grain. Drilling a smaller hole first is usually futile because of that

I took a peek at the chuck & don't see an easy way to get it apart. If I replace it (looking like I will) I'll probably replace the arbour at the same time.

It is not obvious to me that a new precision drill chuck and arbor will help solve your problem.

 

[sean69]

It is not obvious to me that a new precision drill chuck will help solve your problem.

no it won't magically solve the deep hole problem, I agree. But it may solve the reaming problems.

as might a new machine ......

 

[Technical Ted]

I've been wrong before and I'm sure I'll be wrong a lot more down the road, but my gut tells me you have more of an alignment issue than a chuck run out problem.

Do you have a dial indicator you can mount either in your chuck or on the spindle? If so, I would suggest mounting it and take a reading against the three sides of that channel in your jig you put your work pieces in. Run it up and down against the sides as far as you can. It needs to be very close. I personally don't think that laser is a good enough way to line things up within a few thousands so your holes will meet in the middle head on.

Again, I could be wrong, but these are the things I would be looking at before buying a new chuck just to possibly find out I have the same problem after doing so.

Ted