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Tightening a keyed Jacobs style drill chuck would seem to be an action that is in little need of explanation. However, I have often seen people struggle with this and there are countless workshop videos on the net in which poor practice is the norm. This video demonstrates a simple trick which will ensure the best results, everytime.
https://www.youtube.com/watch?v=QwTqwZ8d9l4
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There is a hard to find chart that lists pilot diameter and tooth count of chuck keys. Some chucks [name brands] list correct key size. Some bevel engagement can be cured, lightly - minimally pressing the sleeve toward the chuck nose. Retract jaws and press with a short proper tube or bar so relieved.
My chuck technique is from an OLD machinist, used especially in large sizes.
Open the chuck sufficiently for bit. 'Rattle' the bit some while hand closing the jaws, helps insure small bit contacts all three, very helpful with hand-tight chucks. Then just as Tony emphasizes, lever position perpendicular to axis, I tighten at first hole. Not necessary to exert tremendous force, and never a cheater. You'll now be surprised as you proceed to hole two and three, exerting same force yet achieving more jaw grip. Provided jaws haven't spun too many shanks [usually taps], it will be far less able to do so.
Hand tight chucks work more on torque to hold securely, and they lose it reversing. So tapping [other than hand turned] is rarely successful.
I won't tap with a drill chuck other than initial start by hand, more or less like a tapping stand.
I agree completely.Quote:
Originally Posted by Toolmaker51
I do not like the new hand drill today,with their hand tightening chucks, they never hold a grip,even my heavy duty 1/2 inch Delta!
Yes most are terrible. Made down to a price. The keyed chucks fitted to otherwise similar drills are plain awful too, they generally come with ill-fitting keys.Quote:
Originally Posted by skibo
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Thanks tonyfoale! We've added your Keyed Chuck Tightening Method to our Miscellaneous category,
as well as to your builder page: tonyfoale's Homemade Tools. Your receipt:
<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-keyed-chuck-tightening-method"> <img src="/uploads/228657/homemade-keyed-chuck-tightening-method.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-keyed-chuck-tightening-method">Keyed Chuck Tightening Method</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/chuck-key'>chuck key</a> </div> </div> </div> </div>
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The rattle and the initial closing the chuck by hand is important. Let me add: The more force you have to exert to the key to clamp the bit the more worn out ist the chuck. Don't try to defeat the chuck - buy a new one.
OK - how about tips and tricks for opening a tight jacobs style chuck? I have an old chuck on an older drill which is "frozen". It gets soaked in deisel every time I walk past it, gently heated occasionally - but still no movement in the chuck. Any suggestions?
Thanks,
Des
There are penetrants more effective than diesel. The question that comes to mind is; why is it stuck? Is it rusted, was it over tightened, did it get a bash. Different approaches for each. How are you applying the opening torque, with the chuck key or stillsons etc. Try more than gentle heat.
A Jacobs chuck can easily be disassembled even with a bit in it...
history is unknown - there is some rust visible, but not excessive. I have not tried stilsons - so will try that.Quote:
Originally Posted by tonyfoale
cranked the heat up considerably, and got the stilsons to the party - got some movement, but still a ways to go. I've been doing heating cycles, dripping diesel and penetrene in, then hit with stilsons, once it stops moving, add more oils and gentle heat to pull the oil in. Chuck is now open enough to accept a 3/16" (5mm) drill - started with it completely closed up.Quote:
Originally Posted by desbromilow
I will persevere to get it to the point where it is open all the way, then I can look to remove it from the drill. The drill is a 1940-50 style solid aluminium cased portable electric drill. With pistol grip, and rear D-handle - my intent is to see if I can restore it back to operating, along with the van-dorn drill stand it came with.
As long as we are on Chucks and Keys.........I have a very old Jacobs with what I would call helical key. Looks like the gear in a differential. Anyway I have no key for it and neither does Jacobs. Anyone have a lead or want a chuck if you have a key that you don't want to part with? I could send a photo to anyone interested. Don't know how to post a photo here.
Jim