Thread identification?

[Arnak]

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]

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]

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#]

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]

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]

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]

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]

Hi Jason,

Good idea, thanks for that. ;D

Arnak

 

[techonehundred]

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]

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]

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]

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]

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#]

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

 

[Arnak]

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]

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

 

[Lew Hartswick]

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

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

 

[bezalel2000]

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]

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]

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