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Can my pillar drill be improved

slop in the quill

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Thomas Gude10/07/2017 18:20:38
102 forum posts
23 photos

Hello all,

I own one of these:

nutool pillar drill

It has done me well for quite a few years and can make some quite meaty holes. However I am getting a bit tired of the slop that exists in the quill - there is around 20-30 thou of play and if you are drilling holes <5mm one has to consider what under-size drill bit to use to get the desired sized hole.

Anyway, my question is - can I repair this or is this an integral part of the machine that is worn? I haven't bothered to take it apart yet as I wasn't sure what I'd be able to deduce.

If it's any help the grub-screw and locking nut on the side has about 45° of free movement but is otherwise completely stuck.

Also, as a side note, if you are having a feel around this machine, do not stick your fingers up the 3" hole that exists directly behind the quill whilst the machine is connected to the mains. It will hurt!

Ian Skeldon 210/07/2017 18:55:09
420 forum posts
29 photos

Hi Thomas,

The stuck grub screw that you mentioned is the cause of the problem. The screw has a square machined onto the end of it, which in turn engages into the keyway on the quill. The problem is that this limits adjustment considerably and means that it either locks up and locks the quill or it is left as is and allows lateral movement.

I had the same problem with mine, you need to axtract the grub screw and file it so that you file the square corners off and bevel the head so that it can freely turn inside the keyway, that fixed mine and made it a really useful tool again, so much so that I ended up making a brass shoe that fits into the keyway and is engaged via a hole in the shoe that the grub screw locates into.

ATB, Ian

not done it yet10/07/2017 18:57:05
3941 forum posts
15 photos

Is that 20-30 thou with the quill in that fully(?) extended position? If so, what is it with the quill retracted? Solution might just be raising the table?

Will Bells10/07/2017 20:10:03
152 forum posts
7 photos

Hi Thomas

Many years ago when I was young and daft (yes, I know, just daft now), I tried using a pillar drill for milling.

As part of the progressive beefing up I did, I decided that the quill clearance could be reduced to reduce chatter and make it more suitable for milling. I learned that a milling machine is the right job for milling. A drill press is not.

But, getting to the point, I made a cast iron collar that was a close fit around the quill and was screwed to the underside of the head casting, the bearing bit for the quill.

I actually made it split and adjustable and took all the play out of the quill, which is probably too tight for normal drilling, but the principle may be of interest. Just a thought.

Cheers - Will

john fletcher 110/07/2017 20:15:06
566 forum posts

I had a similar problem several years ago. I think you are referring to that screw with a lock nut just by the return spring housing. If it is anything like mine, the problem was the screw with a four square end and which fits in the long slot in the quill, it had been poorly made, the edges had worn off. I removed the pulley, and withdrew the quill, then made a replacement in bronze. The tricky part is making sure that the square end is correct for the width and depth of the slot. When done it transformed the machine, well worth the effort. John

Bazyle10/07/2017 21:47:39
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4903 forum posts
195 photos

I think there was an article in ME a few years ago about making eccentric bushes for the feed handle axle so that it could be adjusted to push the rack and so push the quill tight up to the front of its housing.

Neil Wyatt10/07/2017 22:27:04
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Moderator
17083 forum posts
690 photos
76 articles

If you take it apart, cut across the housing about 15mm from the bottom with a hacksaw, the split the thin bit and add an adjustment bolt through it (yes I know, how do you drill for he bolt...) you can squeeze the quill to get rid of much of the slop. There are examples of this on line.

On my Clarke version I found the keyway the grub screw bears on was deeper at one end than the other. Set OK for one end it was tight or loose at the other. Some extended and rather hard work with a square 'swiss' file with bend in it made it a more even depth and got rid of the worst of the play.

Neil

Hopper11/07/2017 00:31:33
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3974 forum posts
84 photos

There was also an article in MEW years ago where a gentleman turned a thin sleeve out of thin-walled brass tubing and put it over the quill, with suitable slot for the rack, and loctited it on. I think he must have bored the holes in the body of the drill to suit the larger diameter. He seemed quite pleased with the result. From memory the article was called something like Upgrade for a Low Cost Drill or something. Seems rather labor intensive though so I'd try the other mentioned fixes first!

larry Phelan11/07/2017 10:30:04
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544 forum posts
17 photos

I have one of those drills too,a floor model,bought in 1983. Has given me good service,had no bother drilling 1" holes in 2" x 1" flat for a window guard my friend was making. I think I have some play in the quill as well [not too surprising considering the work it has done ] Might be worth taking a look at it.

Bazyle11/07/2017 10:32:15
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4903 forum posts
195 photos

The more you look at it the more the options come to mind. There appears to be a ring of clear iron at the bottom of the housing that could be drilled in 4 places. Fit two with fixed brass slug bearing points and 2 with loose ones and use a jubilee clip to apply force to the loose ones.

Simon Collier11/07/2017 11:02:17
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314 forum posts
52 photos

There was an article in AME years ago too. I can't remember what was done but it was a daunting job to my mind.

Thomas Gude11/07/2017 11:31:58
102 forum posts
23 photos

Thanks guys, I will look at that adjustment screw and see where I get to.

I tried sliding a sheet of brass shim up there but it ended up crumpling after a couple of uses.

I have seen the cutting a slit in the housing solution online - probably a last resort for me.

Posted by not done it yet on 10/07/2017 18:57:05:

Is that 20-30 thou with the quill in that fully(?) extended position? If so, what is it with the quill retracted? Solution might just be raising the table?

That's fully extended, it's probably 10-20 thou retracted so still pretty bad

Steven Vine11/07/2017 12:16:51
340 forum posts
30 photos

I did the slit modification on a small Chio drill press. In the Chio head, there were two journals that carried the quill. There is absolutely zero play in the quill now, and the machine feels so much better with one less thing to worry about.

dsc00026.jpg

The two domed cap nuts are lightly tightened to close up the slit.

dsc00031.jpg

dsc00032.jpg

 

The test dial moves a mile if I press lightly on the table with my little finger! That's another problem I have to deal with sometime.

I had no qualms doing this modification on a cheap drill press; there was not much to lose. In fact I would go so far as to say that you can't really go wrong by doing it.

By cutting a slit in the two journals, the quill vertical alignment will be slightly altered and the quill will move out of the vertical by a thou as the head casting settles around the quill in a slightly different location. There was a couple of millimeter of play in the quill before it was modified, so the vertical alignment change is not really an issue to me.

Correct me if I am wrong, but I think the slot in the side of the quill, that the screw/lock nut bears on is just there to stop the quill from rotating, and not there to take up any play? Any thoughts anyone?

Steve

Edited By Steven Vine on 11/07/2017 12:26:33

Simon Collier11/07/2017 12:59:59
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314 forum posts
52 photos

I found the article: Re-engineering a low cost Chinese drill press, by Brian Smith, AME July 2001.

Steven Vine11/07/2017 14:38:17
340 forum posts
30 photos
Posted by Simon Collier 1 on 11/07/2017 12:59:59:

I found the article: Re-engineering a low cost Chinese drill press, by Brian Smith, AME July 2001.

I would be interested in reading that article. What is AME?

Steve

larry Phelan11/07/2017 19:36:21
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544 forum posts
17 photos

On the subject of the drill press,did anyone ever try to use one of those tapping head units sold by many suppliers for use in a bench drill ? While they might seem like a good idea,there appears to be no way to prevent them from falling out when you try to bring the tap back up again.There is nothing to hold them in place,so they are little more than useless. I ended up having to modify mine to use it in my milling machine,where I could fit it with a tie bar. I have seen this issue mentioned somewhere before,but I dont recall seeing any answer to it.

Just asking !.

Regarding the drill itself,I find it,s fine for big holes but not so good for small ones,but I suppose if you drill 1" holes,you can,t expect it to drill 5mm holes just as good Still,for the money,it,s OK.

Ian Skeldon 211/07/2017 21:35:16
420 forum posts
29 photos

Steven Vine, glad your table has the same problem mine has, I mentioned that mine moves in another thread about these pillar drills and some super engineer chipped in that in all his life he had never seen a table bend, I took photo's to show how much mine moves with very little pressure from my finger.

For me sorting out the grub screw originally helped a lot, so much in fact that I then went and made a brass slipper for it than runs in the key way, not it is pleasure to use rather than a nightmare.

Andrew Tinsley11/07/2017 21:40:55
959 forum posts

A second bush underneath the table and connected to the table from below in a triangulated fashion, does cure the tendency for the table to deflect.

I have done a lash up to prove the point, but it does mean two devices to tighten when you alter the table height and also you cannot drop the table as far. I am not sure I will do a final version as it seems to give other headaches, must be a better way out.

Andrew.

Simon Collier11/07/2017 22:13:13
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314 forum posts
52 photos

Steve, you have a PM. Also o.p. Thomas.

Edited By Simon Collier 1 on 11/07/2017 22:17:01

larry Phelan12/07/2017 10:07:33
avatar
544 forum posts
17 photos

I too was surprised at the amount of movement in my drill table,just by pressing lightly on it. Not quite sure where it comes from,dont seem to remember seeing it on any of the drills I worked on years ago.Perhaps they were heavier machines.It,s not really a problem,just something we could do without.

All this reminded me of a job I did with that drill some years ago,before I had a lathe. I wanted a number of simple drill bushes to make a drilling jig for my woodwork. Nothing fancy,just a 1" length of steel with a 5mm hole through it.

No one wanted to be bothered with such a small job and those who did gave me mad prices. I ended up buying a length of 12mm silver steel,cutting it to 1" lengths and mounting each piece in the chuck of the drilling machine. I then mounted a center drill in my drilling vice,clamped to the table in line with the chuck and center drilled each piece before changing to a 5mm drill. Did it work? It sure did,much to my surprise. I was amazed at how accurate they turned out. Just for the hell of it,I drilled out a few to 10mm,leaving a very thin wall indeed. I was then able to harden them and fit them to my jig,which I still use from time to time. So,the cheap drills are not all that bad.

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