Haynie
Member
Probably dumb question but I need a four jaw chuck to hold square stock right? Or am I missing something with my three jaw?
Holding square stock
- Thread starter Haynie
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rherrell
Member
Yup! Either that or a collet chuck with square collets.
SDB777
Member
How big dimensionly? Like a bowl blank, or 2x2 spindle? Drive spur not working(or you don't trust it)?
Scott (number of ways) B
Scott (number of ways) B
randyrls
Member
Mark; You can use a spur center, steb center, or safety drive center to turn stock round. You should have gotten a spur center with the lathe.
BKelley
Member
Mark,
For pen blanks on my small Grizzly metal lathe I bought a tapered center spur from PSI and turned the taper off, that way I can hold the center spur with the 3 jaw chuck. Using center drill, I drill each end of pen blank. Then on one end of blank, using band saw I saw a cross about 1/16 deep for the center spur to grab. Use a live center on other end and you are in business. I have used this method on wood and arcylics and so far I have not had the blank slip or go flying off.
Ben
For pen blanks on my small Grizzly metal lathe I bought a tapered center spur from PSI and turned the taper off, that way I can hold the center spur with the 3 jaw chuck. Using center drill, I drill each end of pen blank. Then on one end of blank, using band saw I saw a cross about 1/16 deep for the center spur to grab. Use a live center on other end and you are in business. I have used this method on wood and arcylics and so far I have not had the blank slip or go flying off.
Ben
Haynie
Member
I am wanting to drill 3/4 or 1/2 inch stainless steel.
I figured I needed a four jaw.
I figured I needed a four jaw.
BKelley
Member
Mark,
For turning 1/2 or 3/4 stainless you will need a 4 jaw chuck. They are available in both dependent and independent. Check out LMS.
Ben
For turning 1/2 or 3/4 stainless you will need a 4 jaw chuck. They are available in both dependent and independent. Check out LMS.
Ben
Curly
Member
What kind of lathe are you using. Wood? Metal? Size or model?
I would assume it is a metal lathe because of the forum it was posted in.:wink::biggrin:
Just saying.:tongue:
A four jaw chuck will hold a 'square' blank properly if the blank is really square. If it's not then at least one jaw will not be doing anything.
Some people also remove two of the jaws and hold a unsquare blank by the two remaining opposite jaws. This works well on big chucks with big vee jaws.
Contrary to popular myth, you can hold an uneven squarish blank securely and safely in a decent sized 3 jaw chuck. :wink:
Some people also remove two of the jaws and hold a unsquare blank by the two remaining opposite jaws. This works well on big chucks with big vee jaws.
Contrary to popular myth, you can hold an uneven squarish blank securely and safely in a decent sized 3 jaw chuck. :wink:
Curly
Member
Oh sure. Not only do I have to read, I have to pay attention too!
I got a 4 jaw scroll chuck for my lathe. I had to put it on a backing plate to match the D-5 of the lathe. Runout is less than .001" and I was happy with that. If the blank isn't perfectly square as steve (skiprat) mentioned a shim or two can be placed to centre and firm up the grip. Having a 4 jaw scroll chuck is and asset when frequently gripping square materials. If only needed on occasion an independent 4 jaw is enough and cheaper by quite a bit.
Mine.
SB1313 6" Hi Precision 4 Jaw Scroll Chuck
BKelley
Member
An independant four jaw chuck will hold any four sided workpiece square or not as each jaw is adjusted separately. I think Skiprat is speaking of a dependant four jaw chuck in which the jaws open and close together simultaneously. The independant four jaw chuck is very time consuming, but extremely accurate.
Ben
Ben
Haynie
Member
How?
Haynie
Member
Won't that throw it off center?
No.
A square blank needs a shim on the bottom jaw. You can be selective if you need dead centre, but I only use the same piece of 2mm black plastic.
An UNsquare blank rarely needs a shim. Unless you need a specific spot of course. I hardly ever do this, but rather just 'guesstimate' centre drill the blank on the drillpress and then round it between centres.
Attachments
palmermethod
Member
Not necessarily. Turn a jam chuck with a slight taper so that your square blanks tightly fit. Just saw a Youtube demo of that and it is pretty slick. You may have to re-turn the square end that was in the chuck unless you have a longer blank.
Square into a round hole works. Just taper the hole.
PM