JET 1442 VS Spindle Thread?

[Sticka]

Lathe is 2006 The manual says Spindle size is 1" X 8tpi but Vicmarc 1X8 chuck insert doesn't fit....
Thanks for any help

[Old Croc]

What you will have to work out is the form of the thread on the lathe and the insert, is it 1" BSW, 1" UNC or 1" UN8. None are compatible with each other.
Rgds,
Crocy.

[Sticka]

What you will have to work out is the form of the thread on the lathe and the insert, is it 1" BSW, 1" UNC or 1" UN8. None are compatible with each other.
Rgds,
Crocy.

Thanks for the info.
Frank

[Old Croc]

Ok Frank, it's going to take a bit of detective work to sort out but with the virus you are on the wrong side of the border. Firstly it could be a metric thread, not 1". If you could find a machine shop near you, see if they have any 1" nuts or a metric one you can borrow to try on your spindle and see if they can identify the thread in your adaptor as well. You may find a fitter and Turner that for a few beers might come to your lathe and work it out for you.
Rgds,
Crocy.

[Sticka]

Ok Frank, it's going to take a bit of detective work to sort out but with the virus you are on the wrong side of the border. Firstly it could be a metric thread, not 1". If you could find a machine shop near you, see if they have any 1" nuts or a metric one you can borrow to try on your spindle and see if they can identify the thread in your adaptor as well. You may find a fitter and Turner that for a few beers might come to your lathe and work it out for you.
Rgds,
Crocy.

Thank for your help.
I'll pull the headstock off and take it down to Christensens Machineworks Burleigh.

[Chief Tiff]

What you will have to work out is the form of the thread on the lathe and the insert, is it 1" BSW, 1" UNC or 1" UN8. None are compatible with each other.
Rgds,
Crocy.

1” UNC and 1” UN8 are the same; 1” diameter, Unified threadform, 8 tpi.

Jet are an American company; if the manual says 1” 8tpi it’ll be Unified. Your Vicmark chuck might be 1” 8tpi Whitworth; the threadforms are sufficiently different so that even though the diameters and pitches may be the same the shape of the threads means that they will gall up on each other. Does the chuck screw on about one turn and then get really stiff; but feel like you could force it further if you really tried?

If you want to confirm the spindle thread size you just need an adjustable spanner and a ruler. Tighten the spanner jaws over the threads then measure the distance between them; if it’s a Unified thread it’ll be close to a 1/8” increment (1”, 1-1/8”, 1-1/4” etc), if it’s Metric it’ll be in 1mm increments between 24mm and 28mm. Then put the rule on the threads and measure the pitch; if it’s Imperial the “peaks“ will all line up with the Imperial graduations (every 1/8” inch for 1” UNC); and obviously the same principle will apply if it’s Metric when you put a Metric ruler down.

[Old Croc]

1” UNC and 1” UN8 are the same; 1” diameter, Unified threadform, 8 tpi.

Sorry Chief, they are very close but not the same according to my charts and it also depends on what class of tolerance they are made to.
Hopefully he will sort it out.
Rgds,
Crocy.

[Chief Tiff]

May I ask what charts you are using? All Unified threads are covered under ANSI/ASME B1.1 The link isn’t the standard but is a handy set of thread charts; you’ll notice the 8UN series (where every thread is the same 8tpi pitch regardless of diameter) only starts at 1-1/16 because 1” is already covered under the UNC series. This series is used heavily in my industry (oil & gas) for studbolting purposes.
Happy to learn something new if you are referring to something different?

[Old Croc]

May I ask what charts you are using? All Unified threads are covered under ANSI/ASME B1.1 The link isn’t the standard but is a handy set of thread charts; you’ll notice the 8UN series (where every thread is the same 8tpi pitch regardless of diameter) only starts at 1-1/16 because 1” is already covered under the UNC series. This series is used heavily in my industry (oil & gas) for studbolting purposes.
Happy to learn something new if you are referring to something different?

Probably not, I printed out a whole lot of thread charts from a website to class 3A, a few years ago and I just flicked through them when I wrote the original reply and there was .005" difference between UNC and UN8, so I listed it. For most applications it would not matter.
Hopefully Frank will get it sorted without it being a tolerance issue.
Rgds,
Crocy.

[Paul39]

I wonder if Stika might have a LH 1 X 8 insert: Chuck Accessories: Chuck Inserts

[Sticka]

Definitely Right hand thread, I'm thinking it may be 1 X 10
Machine shop on Monday..... will find out.

[Treecycle]

Could it be that the insert is not actually 1" x 8tpi or in fact damaged in the thread? It would be unusual that the manual would be wrong.

[Sticka]

Could it be that the insert is not actually 1" x 8 tpi or in fact damaged in the thread? It would be unusual that the manual would be wrong.

Brand new vicmarc (stamped 1 X 8)
taking to Machine Shop to check next week.....

[Treecycle]

Did you get any resolution to this?

[dai sensei]

Not sure about yours, but my 2002 JET1442 is a 30x3.5 thread