Drill Press Wobble

[defsdoor]

I've just bought a Jet JDP 17F Pillar Drill from Axminster and it has visible wobble.

Measured with a dial indicator on the outside of the quill it's about 0.2-0.3 of a mm. By the time this gets to the arbor it's about 0.5mm and at the tip of a drill it's more than 1mm.

Axminster are sending someone out to look at it and possibly swap the head but in the meantime I was wondering what amount of wobble is acceptable ? Axminster state "guaranteed concentricity" but put no tolerances to that.

 

[katellwood]

did you try tapping the chuck out and reseating the morse taper (assuming it has a morse)

 

[katellwood]

Here's the blurb from Axi's website stating that the inside morse is guaranteed to within 0.03mm (approx. 1 thou) so the problem may be in the chuck or morse on the chuck

The JET JDP-17F is a very good quality floor mounted pillar drill. Predominately made from heavy cast iron, it is a durable unit designed for busy workshop use. The spindle is supported by precision ball bearings and the Morse taper inside the quill has a guaranteed concentricity of less than 0.03mm. The table is larger than would normally be found on a drill press of this size, able to support large work with ease. A trough around the perimeter is a useful addition. As would be expected with drills of this quality, a quick locking keyless precision 16mm chuck is part of the standard equipment. The powerful motors are rated for continuous operation. Capable of drilling up to 25mm in steel, with a spindle speed range of 160-3300rpm. A precision drill depth stop is fitted as standard. A simple 4" vice is supplied for metalworking

 

[shed9]

I'd measure the internal of the taper with the chuck removed, this will give a more meaningful result than the outside of the quill. Also, don't assume the drill bits are straight, put some machine stock in the chuck and try that.

I'm afraid the Jet 17 has quite a bit of history on the web regarding run out and be prepared to be surprised for what distributors will class as acceptable run out. One mil at tip is unusable, however given the pro-active nature of Axminster sending someone out, I'd also re-assess the situation after this has happened.

 

[shed9]

Doh! someone beat me to it already....

 

[defsdoor]

I measured the outside of the quill purely because it was easy to do and part of the head stock and not the taper or the chuck (which could be inserted offset if there were anything in the way).

I'll do the inside in a minute - although I can't see how there could be a disparity between the outer side of the quill and the inner core are they are clearly turned and you'd assume they would have been turned at the same mount.

I can only find limited information on this drill being problematic though - primarily a post on the Axminster site itself from someone that "increased the bearing preload" and resolved it (if I knew what that meant and how to do it I would have a go )

 

[defsdoor]

hmm - I've just reread this thread and from the answers I've had I think what I might be calling the quill might be something else ? I thought the quill was the bit the arbor is inserted in to (the tapered thing with a key on one end) - and the chuck on to the arbor. As I have wobble on this (which is then amplified the further you get away from it - arbor, then chuck) I eliminated the problem being the arbor and the chuck already.

 

[woodbrains]

Hello,

You're basically right, but to make things clear. The quill is the cylindrical device that moves up and down via the handle. It will have a female taper into which the male taper fits with an interference fit, the Morse taper. This taper is usually tapered on the other end to fit into the back of the chuck, which in turn has a female taper in it. This is usually a Jacobs taper. Your drill might well have something like a No 2 Morse taper to fit the quill (2MT) and a No 6 Jacobs (6JT) to fit the chuck. All these need to be clean and dry for the interference fit; a bit of grit can cause a wobble, if not, cause the chuck fall out completely. The quill mechanism might be a source of eccentricity, but usually not, it just causes poor drilling accuracy - wobble when drill meets work, but not in free spin. The chuck could be bad, if the jaws are not gripping centrally, then the drill will wobble. Poorly made chucks or ones with weak springs do that.

I would not use the word Arbour to describe the parts, as it might lead to confusion. A Morse taper might have an arbour on it, to affix things like sanding drums, but what you have in your basic drill aren't stricly arbours.

Hope you sort out your drill.

Mike.

 

[GLFaria]

Hi,

I found these threads on the topic of DP run-out in a couple of forums:

http://www.chaski.org/homemachinist/vie ... p?p=191726

http://www.practicalmachinist.com/vb/ge ... ion-77776/

Cheers

G.

 

[katellwood]

If there's play in the quill (which normally gets worse the further it comes out the casting) there is a way to reduce it. (but a new machine should be returned)

I cured play in the quill by drilling and tapping two holes from the front into the casting through to where to quill moves up and down. I then inserted two grub screws into these threaded holes ( put a small piece of brass in these holes prior to the grub screws, this should prevent any scratching to the quill) tighten the grub screws so the quill does not move to bed in the brass then slacken off.

I then used two half nuts to lock the grub screws in place when any play had been removed but not so tight as to prevent the return spring operating correctly. this made my old Poolewood drill far more accurate eliminating play completely

The photo may explain better

 

[defsdoor]

Theres no play at all - it's just doesnt rotate true.

I've looked at the parts list - the part with the wobble is called the spindle - the quill is the thing that contains the bearings and the spindle.

The morse tapered thing is called the Arbor also in the parts list - I'm thinkning this is an american thing.

Looking at the setup in the parts list I can only assume that either the spindle or the main bearing is out of true.

I've ran the dial indicator on the inside of the spindle and its definitely not true.

Axminster are sending a guy out with a replacement on Friday - will probably just change the entire head.

 

[skippy75]

whats it like for noise and vibration? I sent two Jet JDP 15 drills back due to that and eventually gave up on them.

 

[defsdoor]

The only problem is the belt cover - the fixing for it is next to uselss (a bolt with a nut on in exposing about 1.5mm of thread to locate to a threaded hole on the inside). This is the only disconcerting source of noise as the bolt doesnt clamp the outer case at all.

I'll re-jig that when I have my issue sorted.

 

[skippy75]

The only problem is the belt cover - the fixing for it is next to uselss (a bolt with a nut on in exposing about 1.5mm of thread to locate to a threaded hole on the inside). This is the only disconcerting source of noise as the bolt doesnt clamp the outer case at all.

I'll re-jig that when I have my issue sorted.

I had a massive amount of vibration from the motor itself, it was shaking the bench it stood on even with the belts off. You are right about the belt cover being the worst culprit for noise tho.

Hope you get your wobble sorted, Axminster have excellent customer service so im sure they will sort you out.

 

[defsdoor]

Been playing some more with this and, whether the drill has settled or something else, I now have no more than 0.03mm of play on the spindle and on the tapered morse.

The chuck does seem out or true though so I might just see if I can swap that and see.

Going back to noise, the belt cover lock mechanism is just pointless, but another source of rattle is the lever that is used to move the motor out. Once the motor slide is locked this lever is under no tension and rattles around. Not sure on the best way to cure this - maybe just needs a rubber olive on it to give it some purchase.

Holding these two issues (literally) theres no other noise other than motor hum and bearing growl.

 

[defsdoor]

To bring this up date, Axminster gave me a different chuck to try and if anything it was worse, so today the nice man from the Nuneaton store arrived with a new drill in the back of his van.

We changed the head and inserted the previous Axminster chuck and it was still visibly out of true - drilling a long bit of wood at one end and the other end flaps around like a wind sock.

I measured the movement on the spindle and it was almost 0 - 1 hundreth of a mm at worse.

So then we used the chuck that came with the new drill and, hey presto!

It looks like the main problem was 2 chucks - both buggered.

Top marks to Axminister for customer service through all of this - I now have lovely smooth drill press

 

[skippy75]

Axminster customer service is fantastic. Wish I could say the same for Jet quality control!