Drill Press tolerances (2)

[Tisorp]

I have observed this forum for the past two years and a few days ago (nervously) posted for the first time. I requested advice from forum contributors regarding the expected degree of run-out in a new, $300, 16mm drill press.With the notable exception of Groggy I have been underwhelmed by the response and was about to conclude that my question must be particularly naive, dumb or uninteresting when I realised I had posted in the "Tools and Machinery" subsection of the "Contacts and Links" forum and not in the "HAND TOOLS AND MACHINERY" forum.
In the hope of catching more notice I am therefore respectfully resubmitting my question(s) as I would like to arm myself with some knowledgeable opinion before reapproaching the seller.

1) What degree or run-out is expected of such a machine as I have just purchased? The best I have been able to achieve with the quill retracted (having cleaned all components and reassembled with the chuck in different positions relative to the arbor) is 7/1000"
2) Can one reasonably expect to improve the situation by fitting an after market chuck?
3)If the answer to question two is ýes` what brands and types are recommended and from whom can they be purchased?

Thanks in anticipation
Jeff

[Groggy]

Jeff, (me again:) )

don't be disappointed with the response as these things can vary. One day you get 10-20 responses and another you get none. Some people will even respond to a 5 year old thread! If you like I can move the other thread over here and merge the two together.

[MurrayD99]

I read your original thread but didn't respond because I don't have a technical answer. It set me to thinking that I'll get a dial indicator and check my drill and other bits & pieces - but time will pass before I get around to it. Having said that, seven thou sounds a lot, especially if it is a metal application. Maybe you could get some specs from a high-end manufacturer. Also, was there not something in FWW on drill presses - a year ago ish.

[MikeW]

Hi Jeff,

I doubt if the manufacturer would give your their manufacturing tolerances, but you may try that route. At least if they were willing you could see if yours was out of spec.

I think there are variables which would need to be accounted for before one concludes the quill or its internal bore is the issue. Most inexpensive drills come with a very low cost check. That is the first component I would suspect.

If you have the ability--and I assume you do--lower the quill enough to check it directly. If you come up with a lower number, subtract it form the 7 thou and that is the amount the chuck is off.

One doesn't have to spend gobs of money on a decent chuck. But the one for my vertical mill was $180 US...and it was a mid-priced decent chuck.

When I bought my Jet floor-standing drill press, first thing I did was swap out the chuck for a good one which cost about $100.

Take care, Mike

[mat]

Jeff

Unfortunately you cannot expect a precision machine for $300. The machining tolerances of these presses is not particularly good. I have recommended on these forums a number of times only to buy a machine that you can check before purchase - there is a large variation. The quill machining is not always good. If you fully extend the quill, back off slightly then feel for sideways slop you may well find some. There is probably more slop in the quill than the chuck. Be careful of buying a new chuck expecting that to fix the problem. Dont throw good money after bad.

However, for woodwork the runout maybe OK for your purposes. It depends what you want to drill and how deep. The best way to go is drill a few sample holes of the type you are likely to drill and see how it goes.

[MikeW]

It's not that the cheap chucks have runout. Instead they do not chuck on-center. Even to the point of variability depending on the size of the drill due to the machining of the bearing surface of the jaws, as well as the jaws themselves.

But you're correct. A $300 drill is a $300 drill. While we always desire near perfect tools for any amount we individually deem reasonable, our expectations are sometimes a tad high.

For drilling wood there can be a much wider acceptable variance than precision metal work. Don't get me started on cheap drills themselves, either...

Take care, Mike

[BobL]

Jeff, How are you measuring the run out? Are you turning the chuck by hand, or actually running the drill? If you are running the drill at too high a speed this can make your dial indicator bounce significantly, dramatically exaggerating the measured runout. Your indicator must also be very firmly clamped down.

Turning the chuck by hand I get the following. Bear in mind, my spindle is an MT3 whereas your is probably an MT2.

"Wobble" (please excuse the decimalized 1000" and mixed units)
As measured against the side of a (keyless) chuck
- chuck fully retracted 0.8/1000"
- chuck fully (80 mm) extended 1.6/1000"

As measured on the end of a 12 mm diam x 100 stainless steel rod. Ie 100 mm of stainless protruding from chuck.
- chuck fully retracted 1.6/1000"
- chuck fully extended 2.6/1000"

Using my (cheap?) cross slider vice I simply cannot reproduce my bit placement to any better than the above

If I run the drill at the slowest speed (160 rpm), the dial indicator vibrates across about 4/1000" against a retracted chuck, to about 8/1000" total runout against the end of the 100 mm stainless rod with the chuck fully extended. I can't see if the indicator is bouncing or not at this speed..

If I run the drill at 3000 rpm the dial indicator swings quite violently about 30/1000" almost irrespective of anything else. This is not right as you can see the dial indicator bouncing and leaving a clear gap between the indicator and the contact surface.

I hope that helps.

Cheers
BobL

[Harry72]

My old highschool teacher showed me a trick for checking a DP, take a short pencil chuck it up place a block of wood on the table and raise it till it just touches... start her up, the circle left is 2x the runout!

[BobL]

My old highschool teacher showed me a trick for checking a DP, take a short pencil chuck it up place a block of wood on the table and raise it till it just touches... start her up, the circle left is 2x the runout!

What sort of sizes of circle were you seeing? I would be concerned if you see any sort of circle with the naked eye. This method assumes the pencil is sharpened evenly and the lead itself is centred in the pencil?

[Big Shed]

And indeed it assumes that the pencil straight as well.

A lot of assumptions there..............

[BobL]

And indeed it assumes that the pencil straight as well.


Sure, so I guess that's why Harry said "short"?

[Wizened of Oz]

My old highschool teacher showed me a trick for checking a DP, take a short pencil chuck it up place a block of wood on the table and raise it till it just touches... start her up, the circle left is 2x the runout!


I wouldn't worry about measurement. If you see a circle throw the DP away.
Just to hijack the thread, I recall, early in my working life, an engineer handed a precision component to the shop foreman.
"This is 2 thou out of round".
The foreman looked at it closely. "Yes. You can see it's out of round".

[Tisorp]

Thank you to those who have replied to my post both for the information and advice. As a result of this I have remeasured my drill press tolerances using the following technique.I don´t have available a trustworthy steel rod as advocated by BobL.

Drill Press table firmly locked. Dial gauge securely positioned on the table.
Quill either fully extended or retracted and rotated by slowly turning the rearmost of the pulley stacks.
Measurements taken from (a) arbor sleeve ;(b)arbor above the chuck,(c) chuck body and 3 different sized bits.
Drill bits inserted 2cm into jaws of chuck (this gives better results than when the bits are further inserted.)
An attempt to measure the degree of movement in the quill when light lateral pressure (with the back of my little finger) is applied just below the chuck jaws. I have called this movement ´Slop`

Results: (units=1/1000")
................................................Quill retracted ..............................................Quill fully extended
Arbor sleeve ..................................... 0.5...............................................................0.5
Arbor (above chuck)............................1 .................................................................1
Chuck body........................................5 .................................................................5.5
3.5mm HSS bit (Sutton,new)................3 .................................................................3
8mm HSS bit (Sutton)......................... 7.................................................................. 7
3/8 HSS (Frost)...................................6.................................................................. 6
Slop...................................................1.5.............................................................. 20

Comments: These figures are somewhat better than I have previously measured due I believe to the technique described above, There is still a significant run-out (wobble) with larger bits and much more than has been described by BobL. The fact that better figures are obtained by not inserting bits beyond 2cm suggests machining problems in the chuck jaws. The better figures also result from avoidance of slop contamination by rotating the chuck from the drive pulleys and not by gripping and turning the chuck directly.

Conclusion: I am probably not going to improve greatly on these figures by purchasing another chuck (If I ever do so I will report the results)
The degree of slop when the quill is extended seems gross but I have nothing with which to compare. All those with a drill press, a dial gauge and some free time please report.
Cheers Jeff

[Harry72]

What sort of sizes of circle were you seeing? I would be concerned if you see any sort of circle with the naked eye. This method assumes the pencil is sharpened evenly and the lead itself is centred in the pencil?
Size... well my cheapass ryobi is about 1.5mm at full stroke:oo:
Yes the pencil must be freshly sharpened, a new Staedtler or Columbia HB pencil are dead centered and very straight:)

Its a simple test that can be achieved in a tool shop without much fuss...

[BobL]

"Light lateral pressure with the back of the little finger" is not exactly very scientific but here is what I got.

0.7/1000" for retracted and about 7/1000" for fully extended

Interesting that's about the same factor (x10) as you got. Please bear in mind my set up is an MT3, and you really should be comparing with an MT2 setup.

I also measured my arbor sleeve and arbor above chuck and got less than 0.2/1000" for both compared to my chuck body which is 0.8/1000", this is also the same approx ratio that you got (1:5).

Given that the limit of measurement, is probably +/- 0.5/1000", the difference between your "on" arbour and "on" chuck is 4/1000". This suggests your chuck/arbour connection is not centred correctly by this amount and a new chuck might make a difference. If it was me I don't think it would be worth it because most bits are not that good anyway. If you want to try a new chuck, McJings have them for only about $25 . It would be good if you can try before you buy.

The difference between the "on" chuck and "on" bit for your chuck jaws appears to be about 1-2 thou' which is about the same as mine. While this should really be checked out by measuring bit run out by rotating the "chuck with bit in" from the arbor, it still suggests the chuck jaws are reasonably central. I must drag out the keyed chuck that came with my drill sometime and see if there is a measureable difference with this one. If you use a keyed chuck you should equally tighten using all three chuck holes to get even pressure and central bit location.

What it really comes down to is how well you can reproduce the hole size and position you want. As far as the 20 thou slop goes, remember when your chuck is fully extended the bit is usually well and truly inside the piece you are drilling. For a twist drill the final bit/hole position is probably more determined by the first cm or two of a drill hole and bit itself. I serious doubt the drill undergoes a 20 thou of slop at the end of a 80mm hole. For spade bits the grain has a lot to say about where the bit wanders off to. For forstner style bits it will be somewhere between the two.

Cheers

[unixbigot]

1) What degree or run-out is expected of such a machine as I have just purchased? The best I have been able to achieve....is 7/1000"


In one of Mark Duginske's DVDs he goes through the process of tuning a drill press. He finds 4thou runout on the spindle and 8thou at the chuck and reports that this is "within tolerance" and "were it twice that I would worry".

HTH,
--chris

[Tisorp]

Thank you to those who have proffered help and advice.In particular thank you to BobL who has obviously gone to some trouble to quantify his own drill press.I am envious of his results.
Prompted by the phrasing of Unixbigot´s post I typed "drill Press" and "tune" into Google and was rewarded with a couple of sites which discuss run-out. Christopher James DeLucci at Wood Central http:www.woodcentral.com/bparticles/DrillPrs.shtml suggests a mamimum acceptable run-out of 5/1000" measured on a rod below the chuck jaws.

I am still interested to hear of other members measured drill press run-out to gain a better appreciation of whether my machine is just average or a lemon.
Cheers Jeff

[BobL]

Jeff, No worries, I have been meaning to measure the runout on my DP for months especially after buy the dial gauge for doing this sort of thing anyway. Once again I remind everyone my DP is an MT3 which is not the same as the more common MT2s. Incidentally I was looking up some specs for a precision metal working drill the other day and they quote a runout of 8/10000".