Author Topic: This is getting infectious - stuck chuck  (Read 4985 times)

Offline PekkaNF

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This is getting infectious - stuck chuck
« on: June 28, 2014, 04:02:10 PM »
Every now and then I see someone asking advice on stuck chuck. Being avid MT user I though I'm already old hand and stuff does not stop me right on track anymore.....you saw it coming.

I have 3-16 mm drill chuck in B16/MT3 arbor that has M12 thread.

Usually I use a slide hammer on M12 thread and a bar chucked into the chuck. Few blows and no drama. I had lend slide hammer to my brother and right now he is away. I tried to use 200mm long  bolt, but it just did not have enough impact.

How about freezing and heating? Chuck it into freezer for half a day and then applied hot air gun into chuck + makeshift impact hammer. No progress.

I had to make wedges. Two hours in total, I had to cleanup etc. After fitting wedges , short application of freeze spray into arbor and two exploratory thumps with a mallet separated them.

Phew.

Pekka

Online awemawson

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Re: This is getting infectious - stuck chuck
« Reply #1 on: June 28, 2014, 04:08:19 PM »
.... now if it had been an R8 self releasing taper . . . .   :lol:
Andrew Mawson
East Sussex

Offline PekkaNF

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Re: This is getting infectious - stuck chuck
« Reply #2 on: June 28, 2014, 04:23:14 PM »
.... now if it had been an R8 self releasing taper . . . .   :lol:

Wow. Never heard of R8 used between drill chuck and MT3 arbour :lol:

Still happy of B18 taper now it has proved to be reliable for drilling. Just to clarify - the lot came off easy from the lathe, but I was trying to remove drill chuck from the MT3 arbour.

Pekka

Online awemawson

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Re: This is getting infectious - stuck chuck
« Reply #3 on: June 28, 2014, 04:50:13 PM »
Should have said so then  :ddb:
Andrew Mawson
East Sussex

Offline vtsteam

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Re: This is getting infectious - stuck chuck
« Reply #4 on: June 28, 2014, 09:06:09 PM »
My homemade mating slotted wedges are in their own special little drawer just above the lathe -- so I won't misplace them as I do so many other things that aren't often used. This forum was my introduction to using wedges for stuck taper separation.

Their specialty is the Jacobs taper......


And ironically enough -- I can't keep the Jacobs chuck ON my drill press spindle for more than a 2 month period, much as I wish it to stay there. It usually falls off at some inopportune moment drilling a fine hole in some important machined part, snapping the drill bit in the hole.

I've cleaned the tapers with acetone before installing, everything perfectly clean, and tapped it in place with a brass hammer. But sooner or later, out it comes. Unlike the 3 donated ball bearing Jacobs Super chucks I received which required beating on the wedges with a sledge over concrete before coming free.  :doh:

Must be a case of Jacobs Law.
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: This is getting infectious - stuck chuck
« Reply #5 on: June 29, 2014, 01:54:27 AM »
I thin I had one Jacobs taper chuck ever, it was holding pretty well.

I am pretty happy with Din tapers they seem to work. Before I just slammed them manually, but once it came free and after that I have been giving them a gentle tap.

Here is pictures of before and after

Online awemawson

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Re: This is getting infectious - stuck chuck
« Reply #6 on: June 29, 2014, 02:02:53 AM »
Glad that you got it off. I keep a set of wedges for each taper size in a linbin for emergancies

Steve,  perhaps a smear of loctite next time you need to reseat your wayward taper?
Andrew Mawson
East Sussex

Offline PekkaNF

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Re: This is getting infectious - stuck chuck
« Reply #7 on: June 29, 2014, 03:10:31 AM »
To my knowledge reaming or grinding is only way to make inside tapers work. I had an HD and it had a taper on crankshaft, it had moved just a few decrees and I asked one racing mechanic. He told that no glue will hold it. clearance is too small and shock loads are too big.

I don't know the newest glues, but I'm sceptical.

Once I did the unthinkable and used very little of valve grinding paste to matte the drill chuck taper (I have no reamer). I was pretty sure I'll ruin it, but it did work. Generally you don't want lap using the actual parts, because grit will embed in some decree, well this is not a sliding fit. Also tapers will generally bellmouth if you try this. And generally tapers will get worse if you lap them, lapping seems to work best on cylindrical and flat, not easily other forms.

Trying to read, experiment and lear about tapers a little. Planning to make a little spindle.

Pekka

Offline vtsteam

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Re: This is getting infectious - stuck chuck
« Reply #8 on: June 29, 2014, 08:41:43 AM »
Well Andrew and Pekka, you guys have me thinking about improving it instead of just living with it.

Maybe I'll just wipe some blue on and see what's happening. If the fit looks good, it's a basic design problem and about the only thing that will help would be Loctite. 

If the fit isn't good it's a manufacturing defect, and then material ought to come off.

But at least I'll find out which it is.

(I do notice that electric hand drills with Jacobs chucks sold here have retaining screws. Why a drill press with a vertical shaft wouldn't need that is a mystery! The weight of the chuck is always applying loosening pressure, the chuck is heavier, and the power is much greater.)

Dollars to donuts,  I won't be able to get it off to blue it!  :lol:
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: This is getting infectious - stuck chuck
« Reply #9 on: June 29, 2014, 09:00:32 AM »
Quote from: vtsteam link=topic=9861.msg110321#msg110321 dateD=1404045703
Well Andrew and Pekka, you guys have me thinking about improving it instead of just living with it.

Maybe I'll just wipe some blue on and see what's happening. If the fit looks good, it's a basic design problem and about the only thing that will help would be Loctite. 

If the fit isn't good it's a manufacturing defect, and then material ought to come off.

But at least I'll find out which it is.

I'm really pleased if my ramblings are of any use. Once I had a dent on one MT3 taper drill and it would not hold, one quick swipe with a file took the bulge away and I still has drill in use.

(I do notice that electric hand drills with Jacobs chucks sold here have retaining screws. Why a drill press with a vertical shaft wouldn't need that is a mystery! The weight of the chuck is always applying loosening pressure, the chuck is heavier, and the power is much greater.)


Hand drills have often that screw there, because people do goofy things with the drill - like use hammer-drill or apply side load - often simultaneously and while sinning latest tunes, tap-dancing and moving drill energetic manner. Normally you don't do that with a pilar drill.


Dollars to donuts,  I won't be able to get it off to blue it!  :lol:

Drill chuck tapers are designed to make very firm contact and they will hold when they are clean. They are not "transitional tapers".

Pekka

Offline Pete W.

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Re: This is getting infectious - stuck chuck
« Reply #10 on: June 29, 2014, 09:06:06 AM »
Hi there, all,

I thought the DIN taper (for drill chucks etc.) was a short section of a Morse taper? 
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest change-note!

Offline Baron

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Re: This is getting infectious - stuck chuck
« Reply #11 on: June 29, 2014, 10:13:21 AM »
Well Andrew and Pekka, you guys have me thinking about improving it instead of just living with it.

Maybe I'll just wipe some blue on and see what's happening. If the fit looks good, it's a basic design problem and about the only thing that will help would be Loctite. 

If the fit isn't good it's a manufacturing defect, and then material ought to come off.

But at least I'll find out which it is.

(I do notice that electric hand drills with Jacobs chucks sold here have retaining screws. Why a drill press with a vertical shaft wouldn't need that is a mystery! The weight of the chuck is always applying loosening pressure, the chuck is heavier, and the power is much greater.)

Dollars to donuts,  I won't be able to get it off to blue it!  :lol:

Many years ago I bought a "Meddings" pillar drill.  It came, new, without any chuck.  At that time it was an extra.  Anyway I also bought a 5/8" (16 mm) chuck.  I don't recall what brand, other than it was somewhat cheaper than a Jacobs, but there was no way it would stick onto the taper.  After a few usages it would loosen.  Even after I smacked it on with a brass hammer, it still fell off.  I complained to the supplier who swapped it for a Jacobs one.  After that one was fitted it never loosened, that one never came off.

At that time I would never have known to blue the shaft and see how good a fit it was.  An old timer suggested that there was probably a burr on the inside of the taper near or at the bottom stopping the mandrel from seating properly.

 
Best Regards:
                     Baron

Online awemawson

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Re: This is getting infectious - stuck chuck
« Reply #12 on: June 29, 2014, 01:39:44 PM »
Taper fitted drill chucks are particularly susceptible to any side pressure, which quickly loosens the taper. This is why you should never hold an end mill in a taper mounted chuck. I think loctite is a perfectly acceptable cure on a drill press where micron accuracy isn't demanded.
Andrew Mawson
East Sussex

Offline PeterE

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Re: This is getting infectious - stuck chuck
« Reply #13 on: June 29, 2014, 03:57:01 PM »
Interesting reading here. I have had some issues with my pillar drills chuck as well, but that was when I "overloaded" it using a dia 20 mm countersink in a 13 mm chuck  :bugeye:

What comes to my mind is a question; Can it be so that the mandrel taper bit is just so long that it bottoms in the chuck and just manages to stick. If so it would be very easy to come off. If a small length, say 0.5 mm is taken off the mandrels end it may go in that final bit to stick properly? Just i guess I'm afraid but perhaps worth checking if just to make sure there is no bad fit.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline Jonny

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Re: This is getting infectious - stuck chuck
« Reply #14 on: June 29, 2014, 04:21:06 PM »
Peter whith the 20mm countersink what that's actually doing is pretty much as Awemason said. Its chaffing and in doing so exerting both vertical and lateral pressure loosening from the taper.
I do things like that daily but with drawbar in to MT, never a problem except when don't tighten up more than finger tight.

I often mill with Jacobs chuck on MT taper mainly due to being idle and never ever a problem.
Current mil was a right swine at first for locking up breaking many a draw bar for years. Easy enough to make, just slacken off around 1/2 a rev then follow through as giving it some. Don't just pat it and lock the quill. I leave a 1lb hammer by the side and usually change as many as 40 times a day and shown how easy to a couple on here.



Offline PeterE

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Re: This is getting infectious - stuck chuck
« Reply #15 on: June 29, 2014, 04:45:00 PM »
Yes Jonny, exactly. I quickly found that out and after the first small scare when the chuck + countersink almost dropped out onto the floor. I also found out how I could manage it to get the result I wanted. I my case, the countersink sort of drills itself into the material creating a down-force which will pull the chuck off the mandrel, but when I followed the downpull properly with the feed handle, it didn't happen again and the countersink was nicely made.

Of course it got hot, so a liberal amount of coolant/lubricant avoided the countersink to stick from heat expansion.

Anyways, my chuck sticks firmly onto the mandrel, but if there is a tolerance mis-fit like too long mandrel taper portion, or too shallow chuck taper "hole", or both, the chuck will not fit securely I think. The differences are minute ....

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline Jonny

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Re: This is getting infectious - stuck chuck
« Reply #16 on: June 29, 2014, 04:52:19 PM »
Seen those pneumatic drawbars, those operate doing the same thing.

Always clean the MT or R8 before inserting, mines had 10's of thousands. As they say practice makes perfect, short sharp blow but follow through the downward stroke.