Jaw equivalency?

[Skew ChiDAMN!!]

I was recently asked a seemingly simple enough question: what's the Nova equivalent to Vicmarc's Shark Jaws? Seemingly simple, until you realise that Nova don't make a one-to-one equivalent.

In my opinion the closest visual match would be the Nova Long Nose Jaws (http://cws-store.yahoostore.com.au/cgi/index.cgi/shopfront/view_product_details?category_id=1107144839&product_id=1107419009). However I believe these are longer than the Shark Jaws, which would mean that they'd handle longer items without tailstock support in compression mode (ie. take a longer spigot) but would have less holding power in expansion mode when used safely. (Assuming that they're used with a std. 5mm recess, unlike pin-jaws which are used full-depth.)

If, instead of looking for a one-to-one match, you're looking for the strongest grip I'd have to say it's the Powergrip Jaws (http://cws-store.yahoostore.com.au/cgi/index.cgi/shopfront/view_product_details?category_id=1107144839&product_id=1107369271) but AFAIK they have no expansion mode capability at all. I don't know that I'd be using them for my goblet blanks, either. Big, humongous bowl blanks, yes. Goblets? Nar, I'll pass. ;)

Personally I use the Nova Spigot Jaws (http://cws-store.yahoostore.com.au/cgi/index.cgi/shopfront/view_product_details?category_id=1107144839&product_id=1107369268) because with the thicker material at the base I feel safer giving that extra twist to the wrench when tightening, meaning more power to the grip in either mode. Slightly shorter than the Shark Jaws and the extra material at the base means less clearance to to the chuck body in expansion mode, but there's still enough clearance to safely make touch-up cuts and sand the base of the bowl up to the lip of the recess. To my mind, these are the closest to the Shark Jaws in terms of actual use.

Now, I don't have the Shark Jaws myself, although I have used 'em elsewhere, so I can't do a direct comparison. I'm interested in what others think, though... what would you say is the Nova equivalent?

[benji79]

I just got my first nova chuck yesterday. now today while turning my first evet goblet, i found as soon as i put a bit of pressure on the piece it wanted to move off center, no matter how hard i tightened it. The spigot jaws look like just what i need. Heaps of area to grip on.

[Sprog]

I just got my first nova chuck yesterday. now today while turning my first ever goblet, i found as soon as i put a bit of pressure on the piece it wanted to move off center, no matter how hard i tightened it. The spigot jaws look like just what i need. Heaps of area to grip on.

Benji,

Were you using the standard 50mm jaws that are supplied with the Nova chucks?
These jaws have tremendous holding power and I would have thought they would be adequate to hold a blank for a goblet.
Could you describe the method you used to secure and turn the goblet?
Could be something other than the jaws.

[Skew ChiDAMN!!]

The 50mm jaws really need a shoulder on the spigot for maximum grip, and a bevelled spigot. For goblet sized blanks, they should be used in conjunction with the tailstock, but goblets are do-able with them provided you keep in mid that there's a lot of leverage involved when hollowing out. Lotsa light cuts with very sharp tools are needed,

I find the spigot jaws ideal for goblets, it's what I bought them for, and with 'em I don't need the tailstock for support at all. :) Better still, I use a homemade Olsen style tool for hollowing and Hoooey! Can that beasty hog it out! :D

[benji79]

I think i was trying to make it to long. It was hard wood and about 9-10 inches long.... As i said, first time. I then went to some softer wood and made it about 8 inches long and it worked a treat. As i was trying to hollow out the longer one, the chisel would dig in a bit and throw the whole piece of its axis. Proby trying to jump in to fast..:rolleyes:

[robatman]

Hey Skew,
by superjaws do you mean shark jaws or is it something diff,
I did a search at jim carrols site and only found shark jaws.
Robert

[Skew ChiDAMN!!]

Hey Skew,
by superjaws do you mean shark jaws or is it something diff,
I did a search at jim carrols site and only found shark jaws.
Robert

#%^&$#! :o

Yeah mate, I meant Shark Jaws. I'd better go back and edit that...

[Jim Carroll]

Jaw comparison.
The jaws do similar jobs but do not look the same.
You have the 35 &45mm spigot jaws from Nova or the 35 & 45mm shark jaws from Vicmarc
The power grip jaws 100mm fit on the supernova chuck or the titan jaws 130mm for the Nova Titan chuck.
Vicmarc have Cup jaws that are 45mm, 65mm or 110mm but only fit the VM120/140 chucks

I would not personally use any of the jaws in an expansion mode due to the extra pressure you would need to make them work. And the extra chance you may split the timber.

They are all primarily designed to work in the compression mode so you can squeeze as much as you like.

[rsser]

The bevelled outside edge of the Nova spigots are a pill I reckon. Yes, it gives you a smidgin more access but rules them out for expansion mode except with a stupidly deep recess. (While in whinge mode: the rounded over edges on both sides of their 75mm bowl jaws reduce the bite considerably; good case for a workover with a milling machine to flatten the top).

I've done a lot of expansion mode work with the Vicmarc shark jaws on small to medium bowls, boxes and pencil jars and never had a problem. Now of course having said that the next one will prob crack :(

btw, I've just roughed out Vern's monster lump of gidgee by mounting it to Titan Powergrips with the 130mm faceplate ring. Very solid setup but got the tailstock up for insurance nevertheless.

Broke one square drive screw mounting the plate so predrilling seems to be the order of the day in very dense wood (using a mix of 8g and 12g screws); and she's not well centred but moving the faceplate should be no drama.

[Skew ChiDAMN!!]

The bevelled outside edge of the Nova spigots are a pill I reckon. Yes, it gives you a smidgin more access but rules them out for expansion mode except with a stupidly deep recess. (While in whinge mode: the rounded over edges on both sides of their 75mm bowl jaws reduce the bite considerably; good case for a workover with a milling machine to flatten the top).

Hmmm... looks like a design change. Why, I've no idea but I have to agree that it's a stupid idea.

Here's a pic of mine; as you can see they're dovied like the std jaws, except they'll work in a deep recess as well. When used in a deep recess they have humongous gripping power in expansion mode, with less chance of blowing out the lip. That reduces clearance though... I usually only use a "normal" recess and use the clearance for tool access.

Actually, I don't remember the last time I used my std. jaws... these practically live on my chuck, occasionally swapped over for pin jaws. That's probably more a reflection on the types of items I enjoy turning than anything else. [shrug]

[rsser]

Interesting.

Mine look nothing like that - pic attached. Prob missed something.

I never use them as you can see.

[Skew ChiDAMN!!]

Mine are exactly the same on the inside as yours, just the outside is different. :confused: Maybe people have been using them with short stubs, causing flex/fractures at the base of the jaws?

Ah well. BTW, if you ever want to reclaim the shelf-space take up by your jaws, I can send you my postal address... ;)