# Thread identification?



## Arnak (Jun 11, 2012)

Hi Folks,

I am considering purchasing some ER collets for my Warco BH600G lathe.

I would need a spindle nut but I am unsure of the thread.

The OD is 56.89 mm  2.239" x 10TPI as far as I can tell.

Has anyone any idea what thread that is?

I have tried to get the angle with thread gauges but the depth of the thread is so much that my gauges are to sharp a point to fit full into the thread. :-[

Thanks for any advice.

Arnak


----------



## Jasonb (Jun 11, 2012)

Are you talking of putting the ER collets into the spindle nose?

It won't work as the spindle is MT

You either need MT collets or an ER holder.

J


----------



## Arnak (Jun 11, 2012)

Hi Jason,

Sorry I most likely called it by the wrong name.

Perhaps I should have said a collet chuck, the sort where you can fit it directly to the spindle nose and have the material run right through the spindle.

I've seen a picture of one somewhere. ???

Ah, just found it :-

http://www.homemodelenginemachinist.com/index.php?topic=17925.0

Someone had made the chuck and just brought the er nut to fit.

Arnak


----------



## mu38&Bg# (Jun 12, 2012)

I would have to guess that's 2.25"-10. It's highly unlikely to be M57x2.5. In the metric system you would not choose an odd size (57) in a thread that large.

Grind the sharp points off your thread gauge. You will not run into a 10 TPI thread with sharp thread roots.

Greg


----------



## techonehundred (Jun 12, 2012)

Here is everything that you ever wanted to know about ER Collet chucks. All the different types and sizes. This is what I used when designed my chuck which you linked to above. 

http://www.takayama-shoji.co.jp/rego/pdf/13_technical_information.pdf


----------



## Arnak (Jun 12, 2012)

Hi Diesel Pilot,

Thanks for the reply, yeah, that was nearest guess, thanks for confirming it.

Grind the tips of my thread gauges :'( You vandal.. :

Hi Technohundred,

Thanks for your reply, that will be very useful. ;D

Now where can I get a 2.25 x 10tpi tap. ??? Just kidding. 

Arnak


----------



## Jasonb (Jun 12, 2012)

Why not just grind a HSS tool to suit the thread angle testing against the spindle then mount it in a boring bar to cut the internal thread.

J


----------



## Arnak (Jun 12, 2012)

Hi Jason,

Good idea, thanks for that. ;D

Arnak


----------



## techonehundred (Jun 12, 2012)

Arnak  said:
			
		

> Now where can I get a 2.25 x 10tpi tap. ??? Just kidding.
> 
> Arnak



A 2.25" X 10 would be a strange size for spindle threads, is there any chance that it is 2.25 x 8? If so, you would be building the duplicate of my chuck. The only reason I mention that is a quick search lists this lathe the same as a Grizzly 9249 which lists a 2.25 x 8 spindle.


----------



## Arnak (Jun 12, 2012)

Hi Techonehundred,

Good question, the spindle thread is only .5" long and from crest to crest over the length is 5 tpi so I have to assume it is 10tpi.

I could try a thread tool in the tool post with the gearbox set to 10 tpi and just see how it matches.

Arnak


----------



## lordedmond (Jun 12, 2012)

using a bit of google fu

your lathe is sold in the USA as a G9249 



according to their spec sheet the spindle thread is 2 1/4 8 TPI  no comment on the angle though but I suspect its 55 deg as its an imp thread


Stuart


----------



## Arnak (Jun 12, 2012)

Hi Stuart,

Nice one. ;D

How did you find that out? ???

I did check google extensively but didn't see a cross reference anywhere. 

I'm sure I read somewhere on this board that they are very similar to the Chester lathes.

I did check the Chester page and found a similar lathe with a spindle size of 2 1/4" x 8 TPI but wasn't sure if mine was 8 tpi so now I know...brilliant!

Arnak


----------



## lordedmond (Jun 12, 2012)

I should have copied the page alas I cannot find it agin

but look on the grizzly site with their number and check out the pic parts and manuals are free to dl

Stuart


found it here is the quote from the page

Later I then bought a Warco BH600G lathe (also known as the G9249 in the USA) and so asked Gray if he would further expand his design to include my new

Link http://www.homepages.mcb.net/howe/bh600 screw cutting.htm


----------



## mu38&Bg# (Jun 12, 2012)

Arnak, sorry I thought it was your thread pitch gauges that didn't fit. Now I see you were checking the angle.


----------



## Arnak (Jun 12, 2012)

Hi Loredmond,

Great, thanks for the link. ;D

Hi Dieselpilot,

You were right actually, both my thread gauges and my angle gauges didn't fit. 

The thread gauges didn't go big enough except for the metric but that was the wrong pitch and the angle gauges were to sharp on the point to go in far enough... 

I will cut a bit of brass to 55 degrees and 60 degrees with a blunt end to see which is correct, I suspect 55 will be right.

Stuart, thanks for the clutch page, I have copied that to my hard drive. 

Arnak


----------



## techonehundred (Jun 12, 2012)

i did mine with 60 degrees. so that would be my bet.


----------



## Lew Hartswick (Jun 14, 2012)

Arnak  said:
			
		

> Hi Techonehundred,
> 
> Good question, the spindle thread is only .5" long and from crest to crest over the length is 5 tpi so I have to assume it is 10tpi.
> 
> ...


Don't forget to count "spaces" not the point at each end when doing that.
  ...lew...


----------



## bezalel2000 (Jun 14, 2012)

Hi Arnak

I understand that 55o only applies to whitworth thread form

and at 2-1/4" BSW is 4 Tpi and BSF is 6Tpi

the thread / diameter ratio is more in line with UNEF but the largest standard pitch seems to be 18 Tpi 60o

It looks like cutting your own is likely to be the quickest fix. 

Bez


----------



## Blogwitch (Jun 14, 2012)

Bez,

Not just Whit, but BSF and ME threads also use 55 degrees, and most probably a few others as well, but these three are the most common ones used.

BTW you could have a 12" diameter shaft with a 0.5mm pitch metric fine thread on it, there is no distinction when it comes to cutting your own, only standard threads use standard pitches or TPI.

John


----------



## Arnak (Jun 14, 2012)

Hi Lew,

Good point or space come to that, I was counting the tops of the thread so I expect that counting spaces would bring it to 8 tpi. ;D

Hi Bezalel,

I agree, cutting my own thread appears to be the best way to go, other than purchasing a back plate which is about £60 then the ER32 fitted to a smaller backplate at about £50 and that is before I buy the collets. :'(

All I need now is a large diameter of steel. 

Arnak


----------



## Blogwitch (Jun 14, 2012)

Arnak,

Will this post help you at all?

http://madmodder.net/index.php?topic=2249

If you swap your dimensions for the Myford ones at the beginning, then screw it onto your spindle nose, then follow along the rest of it dot by dot.


John


----------



## Arnak (Jun 14, 2012)

Hi John,

Very nice, thanks very much for that. ;D

I've bookmarked it for reference.

Arnak


----------



## bezalel2000 (Jun 14, 2012)

Bogstandard  said:
			
		

> Bez,
> 
> Not just Whit, but BSF and ME threads also use 55 degrees, and most probably a few others as well, but these three are the most common ones used.


Thanks John
I thought all Brittish 55o threads since about 1850ish were all whitworth form (ie same root shape and same crest shape) including BSW, BSF, BSP and BSB etc. (all those not 55o are not whitworth form) BA, BSC, Acme etc.
 Is that not the case?  ???

Bez


----------



## Blogwitch (Jun 15, 2012)

You are quite right Bez, I wondered why you came back with such and understated reply, not like you at all.

I had misunderstood your text, purely because I tend to refer to a thread by what it is, rather than it's form.

BTW, two of my favourite heroes, Ike Brunel and Joe Whitworth.


John


----------

