Pillar Drill Accuracy - Do I need a new chuck?

[Racers]

I used to do the 3 hole tightening trick shed drilling holes in walls with a hammer drill it was the best way to stop the bits coming loose, don't need to do that with a SDS drill.

Pete

 

[HappyHacker]

I have had a Clarke pillar drill for about 10 years, it had little use for most of that time and recently I had difficulty with the runout, clearly visible, which had been OK when new. I tested the chuck and the MT arbour with a dial gauge and the chuck appeared to be the problem, I cleaned it but with no improvement. Put a new one in and all is well again.

I have no idea why the chuck developed runout as it had little use and was always treated well. I had never heard of using all the three holes to progressively tighten the chuck but it makes sense.

 

[Cordy]

My Sealey bench pillar drill from Machine mart, bought 18 years ago -- developed a wobble
So I bought THIS and now it is drilling quite decent holes again

As a bonus; no more chuck key

 

[Eric The Viking]

Similar experience here:

I now use a Rohm keyless chuck (very similar to the one on eBay above) for small work - it is brilliant.

There is one issue though - it tightens (centrifugally?) as you spin it up, so you have to remember not to overdo it when locating the drill bit, otherwise it won't release at all easily, especially when larger bits are being used.

For a long time I thought I had bought a dud though: My Rohm is threaded, rather than Jacobs taper, and the thread on the MT2 adapter was bottoming inside the chuck, so the precision back of the chuck didn't meet the flange on the adapter. Eventually I took time to look at it, realised I had nothing to lose, and hacksawed about 3mm off the end ofthe MT2's thread. Problem solved.

I really like the Rohm, with one tiny niggle - it's hard to see where the jaws are sometimes and thus you can initially pinch a small drill bit between two of them, rather than all three. But that's minor.

The chuck that came with my Clarke has massive runout in comparison.

E.

PS: I'm with Jacob regarding keyed chucks - have always snugged up and tightened using all three holes. It's how I was taught to do it working in a light engineering factory - 3-jaw lathe chucks and Jacobs-style chucks both needing the same technique ( -ish), for similar reasons.

 

[AES]

If it's of any help at all I was also taught to use all 3 key holes to tighten Jacobs-type drill chucks - but NOT over-tighten!

And for EtV - I too tend to get small drills between the jaws of my keyless Rohm chuck if I'm not careful! Getting old I guess (me, not you Eric). ;-)

 

[Deadeye]

One other thought before you run off and get a new chuck.
When you got the 0.04mm reading on the arbor, did you check that all the way down and especially at the very tip?
Any anomaly at the tip of the arbor will result in a disproportionate wobble in the chuck and hence the bit. If you have some engineer's blue it might be worth just checking that the mating surfaces all join up evenly.

 

[jonclancy]

Thanks for all your thoughts and guidance. I’ll pick up some Engineer’s Blue over the next couple of days. I measured the arbor in one spot, but will re-measure down to the tip. A new arbor is less than a tenner. The chuck about four times as much!

Cheers!

 

[Deadeye]

https://www.google.com/search?client=fi ... Pt67GgCA22

Further to my post above - this sounds like exactly your issue

 

[John Brown]

I was taught by my father to tighten a drill chuck by moving from hole to hole. I don't really understand why, but as he'd served his time as an engineer in the Merchant Navy, I assumed he knew what he was doing.
Could be total nonsense of course - nobody's infallible.

 

[jonclancy]

Googlebooks link has it... use a hammer!

Great link, thanks!

I have some Engineer’s Blue on the way...