Chuck problem

[Nige52]

Hi guys,
18 months ago I bought the 70mm Viper 2 chuck and several sets of jaws for it. I have had no problems whatsoever so far as it's done everything I asked of it, till today........
I needed to drill a hole in the center of a 1" Delrin disc I had, 1/4" thick, no problem I thought so I removed the chucks standard jaws and replaced them with the set of V2PJ Pin Jaws which according to the blurb open up to 32mm and go down to 8mm.
Upon opening them up, the most they'll go to is about 23mm, not 32mm. I'm sure that in the past I've used these jaws for 1" stuff (25mm) so cannot for the life of me see why they hit the stop before they're open wide??? I took the back plate off to see if there was anything obvious, but there isn't, everything is clean as a whistle inside.......any ideas anyone please?

 

[stewart]

Might be completely wrong, not knowing this chuck at all, but how many screw holes do they have? My Nova pin jaws only have one screw hole....if yours are the same, might you be screwing them into the wrong hole on the jaw carrier??

 

[CHJ]

How are the jaw carriers retained/stopped?
I presume from your description they are normally retained and don't come out.
Has something moved or dust debris got compacted or trapped in a location grove or suchlike against a retaining stop?

If the latter's the case it may be a case of removing stop pin or screw and taking carries completely out of the scroll to clean things out.

 

[Robbo3]

Hopefully there is no damage & it's just a build up of debris. Either way, seems like a strip down, clean & reassemble would be beneficial.
From memory - Remove the back plate to gain access to & knock out the roll pin which acts as a stop for #4 carrier. All the jaw carriers can then be removed in order 4,3,2,1.
Reassembly is the opposite, 1,2,3,4. The jaw numbers don't have to match the carriers but it makes it less likely to get it wrong if they do. If you can't find the numbers, turn the carriers upside down & the one with the shortest distance between the first tooth & the nose is #1, the distance getting progressively greater to #4.

Just be aware that I've come across one chuck where the numbers were incorrectly stamped. Using the above method sorted out the correct assembly. They were then numbered with a marker pen & the owner sent happily on his way.

 

[Nige52]

Robbo3,
Many thanks for the stripdown I've done exactly as you said and found no damage internally, everything looks as new, there was very little debris at all....the roll pin you refer to, do you mean the raised grub screw sticking up in channel 4? I have found that it's because of this sticking up grub screw, that the jaws won't open any further, I've tried screwing it down more, but it's at a full stop and the jaw still backs up to it then stops........?
Should this grub screw actually stick up? When I removed it the jaws worked perfectly, but of course now there is no stop.....
Cheers
Nige

EDIT: I should say that jaw 4 is in the correct position as it is the only one that has a small recess in the back..here are some pics with the grub screw in, and with it removed. The last pic is where the jaws should open to.......

 

[Nige52]

Well well well...........look what I just found on the net :roll:

http://www.sheriffonline.co.uk/charnwood-viper-2-scroll-chuck-review/

Now I know.......remove the grub screw....... 8)

 

[woodpig]

Ah Ha, glad you've got it sorted! :lol:

 

[Nige52]

I've emailed Charnwood asking if my chuck is faulty as the jaw carrier hasn't been channelled out far enough......

 

[Dalboy]

To me if the the company state it will do a certain size and it does not then surely it is false advertising and should either change the specs of make sure the item does what they claim.

 

[Nige52]

I agree Dalboy :wink:

 

[woodpig]

I've emailed Charnwood asking if my chuck is faulty as the jaw carrier hasn't been channelled out far enough......

Yes, it sounds like it's a slight error on the machining. Many chucks don't have a "safety" screw fitted though, my Axminster Clubman doesn't.

 

[Robbo3]

Obviously it's much easier to diagnose faults with the item in front of you on the bench.

Meant to say that mine is not the Viper but the Rutlands XT650Kit version. Thus it has a roll pin as a stop & yours a grub screw, presumably accessed from the top & therefore no need to remove the back cover plate.

As mentioned, some chucks don't have a stop so some care must be taken not to over extend the jaws when used at their maximum capacity.

I agree with Sheriff's remarks in his blog that you linked to. I would leave the grub screw in place but remove it when needed for larger work then replace it when finished.

Stripping your chuck & reassembling it has at least given you an insight as to how it works.

 

[Nige52]

It sure has Robbo
Let me just say that I am very pleased with the quality of the chuck and jaws, apart from this oversight on the milling process on No 4 Jaw Carrier, I can't fault the set up, it's a smashing chuck for the price and very suitable for Midi lathes as my Axminster is.
I also have a micro lathe, the Proxxon DB250 which I use for very small pieces and I've turned loads of pens on it, I bought the 4 jaw chuck for it and have had it to pieces a few times for oiling and cleaning so know the 4321 - 1234 routine fairly well, this chuck doesn't have a stop and it's easy to over extend the jaws, which I have found out......

Whilst typing this out, Charnwood have phoned me and apologised for the faulty jaw carrier and have already posted a brand new full shiny set of carriers to me! Now that's service! Thanks to everyone for their help on this, just what a good forum is for
Cheers
Nige