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Learning to dial in a 4-jaw
- Thread starter DavidR8
- Start date
- Joined
- Mar 25, 2013
- Messages
- 4,616
That knurled knob has a 2" OD. Yes I would use the original wrench for the final tightening. My key fits very nicely so duplicating it would be perfect. I still do not understand the nominal size it is supposed to be!
Robert
Robert
- Joined
- Apr 14, 2014
- Messages
- 3,152
What size chuck are you intending to use these keys on? Most of my 4 jaw chucks are in the 8" to 12" range. I doubt I could get enough leverage on a 2" diameter knob to even move the jaws let alone snug them in place. About the only ones I can see them working on are a couple 4, 5" ones, and an 8" one for the Seneca Falls lathe. The jaws on the 4" and 5" ones are pretty small. The 8" one is worn to the point the jaws sound like castanets when the chuck is rotated without anything in the jaws.
I have not seen an 8.5 chuck key either.
The socket on my 8'' four jaw measures .407''. The key measures .393''. I consider the fit to be very good.
The DIY stubby keys I made up measure .374'' and work well for what I do with them.
May I ask why you need to determine the nominal dimension of your key?
My thanks to David for his positive attitude.
rwm, those should work great for some finger wrenches. If they don't then your chuck would need some maintenance or troubleshooting.
As previously mentioned by projectnut your keys would have to be long enough for the knurled section to clear the top of the jaws in their safe full open position. Sorry to mention the obvious.
In my case I traded off some of the length required to fully open jaws in order to have more compact tools for the smaller dimensions I usually have to chuck.
- Joined
- Mar 25, 2013
- Messages
- 4,616
The chuck in question is a 6" Southbend brand. It is new and made in Taiwan so I am expecting metric. There is really no reason I need to know the nominal dimension since I will duplicate the key, I was just curious if the size was made to a standard. The jaws are tight but I believe a 2" diameter will be enough to turn the adjuster.
My next task will be to figure how to attach the stem to the knob. I have a few ideas including cross drilling with a roll pin. I could braze it but would likely discolor the knurl and have difficulty cleaning it. Epoxy would likely hold for this application especially if I sandblasted the surfaces first. FYI the knob is reamed to .500". I would have made these but I have a knurling disorder especially on stainless!
Robert
My next task will be to figure how to attach the stem to the knob. I have a few ideas including cross drilling with a roll pin. I could braze it but would likely discolor the knurl and have difficulty cleaning it. Epoxy would likely hold for this application especially if I sandblasted the surfaces first. FYI the knob is reamed to .500". I would have made these but I have a knurling disorder especially on stainless!
Robert