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Teknatool's 'Power Grip Jaw Set'...

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Forum topic by ScrubPlane posted 09-02-2013 09:20 PM 1171 views 0 times favorited 5 replies Add to Favorites Watch
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ScrubPlane

190 posts in 1662 days


09-02-2013 09:20 PM

Topic tags/keywords: lathe turning tip question

I could use some guidance/suggestions from anyone experienced with Teknatool’s Power Grip jaw set. These jaws appear to have the ‘depth’ to hold a tenon upwards of 2” long whereas the manual says only 12.5mm (sorry about not doing the metric conversion).

Questions include…

Does anyone have experience with these jaws and holding pieces ‘deeper’ than 12.5mm?
Is this an error in Teknatool’s documentation or am I reading it incorrectly (see pg 29-30 of the attached link)?

http://www.teknatool.com/products/Chuck_Accessories/Jaw_Sets/downloads/Accessory%20Jaws%20Manual.pdf

I’ve ‘rough turned’ a twelve inch tall camphor wood vase and am now getting ready to complete it as an anniversary gift for my wife. The blank was very expensive so I’m taking my time.

Any thoughts would be appreciated…thanks, John


5 replies so far

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Wildwood

1887 posts in 1601 days


#1 posted 09-02-2013 09:51 PM

I do not own a Nova chuck, but these jaws came up for discussion year or so ago over at woodnet.com. Guy that asked about these jaws bought them and very haqppy with them. Think they are saying tenon should not be longer than 12.5 mm or 1/2”.

http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=packard&Product_Code=113122&Category_Code=

-- Bill

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Wildwood

1887 posts in 1601 days


#2 posted 09-03-2013 10:31 AM

Would Nova 35mm or 45mm spigot jaws work better for your application?

They do have a speed warning listed not to exceed 648 RPMs in contraction mode. Assume they do not want you turn at higher speed without tailstock support. You see the same warning for Power grip jaws.

http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=packard&Product_Code=113116&Category_Code=

http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=packard&Product_Code=113117&Category_Code=

They are providing min-max specs in both mm’s and inches for all their jaw sets. When using a tenon I seldom ever use entire depth of jaws, unless using my Talon spigot jaws gripping 1/4”to 1” dia tenons.

-- Bill

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mpax356

67 posts in 1959 days


#3 posted 09-04-2013 12:57 AM

You are reading it correctly. The strength comes from the shoulder fitting against the face of the jaws. You just don’t need longer than 1/2” tenon. Longer does not make it stronger. Unlike the 50mm jaws, the Power Grip jaws are a true dovetail so cut a clean dovetail 15 degree angle. This jaw set should provide a stonger hold on large pieces than the spigot jaws (I have both) with less vibration because of the larger tenon.

-- MPax, Atlanta

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ScrubPlane

190 posts in 1662 days


#4 posted 09-04-2013 10:31 PM

MPax…While what you’ve written makes sense I’m still somewhat confused by what I ‘see’ in front of me. Questions…

If my tenon truly only needs to be 1/2”, then why are the jaws so deep?

Also, at the bottom of the jaws (nearest the chuck) there is what appears to be a wide screw pattern as if the inside of the chuck is forming a gigantic machine nut around which to grab the wood. What purpose would this possible serve?

thanks…

View JTJr's profile

JTJr

11 posts in 2141 days


#5 posted 09-06-2013 04:25 AM

The longer jaws can assist by moving the base of the bowl further away from the headstock, giving better access to the bottom of the bowl.
The can reach further into a a vessel or box in expansion mode.
The rings further down, might assist in biting on to a blank being roughed, other than that I don’t know, because I don’t have them for my Nova SN2 chucks.

All in all, they are for a larger tenon / spigot (3 3/8 ) or recess ( 4” ) for larger work than the stock 50mm (2”) jaws, by giving a larger platform to resist side thrust and more clamping area.

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