WM250 thread cutting

[Mark P.Participant @markp]

It appears like that in my photo but the 30T is being driven by the 50T gear with the 45T in front of it. Not much a photographer.

Mark P.

[SillyOldDufferModerator @sillyoldduffer]

I think Cabinet Enforcer is right; the 30t is clearly driving the smaller of the two gears which must be the 45.

I think you have the 50t and 45t the wrong way round. And, looking at the photo, it looks as if the 30t will reach the headstock after you swap 45t and 50t over.

Could be a classic case of seeing what you expect rather than what's actually there. I do it all the time…

Dave

PS I still think the 30t is only an idler.  Trouble is the more I think about it the more confused I get!

 

Edited By SillyOldDuffer on 22/09/2017 15:35:41

Edited By SillyOldDuffer on 22/09/2017 15:47:04

[JourneymanParticipant @journeyman]

Yep! definitely looks the wrong way round. The 50 tooth, nearest the bottom of the image, is clearly overlapping the 30 hence the gear nearest the top is the 45.

Dave, yes it is an idler in this setup you could use any size in place of the 30

John

Edited By Journeyman on 22/09/2017 16:01:39

[JasonBModerator @jasonb]

And just to rub it in yes the 30 should be in contact with the 50T

The chart on the front of your machine has the 50T on the right and 45T on the left looking from the front of the lathe you don't

[Mark P.Participant @markp]

Jason, I have the 50T on the right hand side ie next to the headstock with the 45T on the left, the 30T is in contact with the 50T the 45T gear is in contact with the 85T leadscrew gear have a gap of 4.5-5mm between the 30T and the spindle gear!
Mark P.

[JasonBModerator @jasonb]

I've just blown up the image and it does look like the 50T is towards the banjo. The 30T is obscuring part of the larger 50T

So best bet is to fit something larger in place of the 30T, probably have to be the 55T or 60T. Then put a dti on the carrage just to make sure you are moving the right amount per turn of the chuck

[Mark P.Participant @markp]

Thanks Jason, I thought I had set it up correctly, I think I may have a longer banjo fitted! I suppose I could machine a bit off the top of my banjo.
Regards Mark P.

[JasonBModerator @jasonb]

I do seem to remember reading of someone making there banjo smaller.

[JourneymanParticipant @journeyman]

Mark, you are absolutely right. I tried this setup on my WM250 and it doesn't reach the spindle gear. It does however work with a 60t in place of the 30t. In doing this I also leant that spacer washers can travel great distances and hide in strange places when dropped. Spent an hour trying to find the one that threw itself into the lathe drip tray and bounced so that I could put the gear train back again hey ho! Trouble is I havn't got enough hands to hold everything in place.

John

[Mark P.Participant @markp]

John,I know exactly what you mean about not having enough hands! I am thinking about making a new shorter banjo when I have a bit of spare time.
Mark P.

[SillyOldDufferModerator @sillyoldduffer]

Posted by JasonB on 23/09/2017 13:10:23:

I've just blown up the image and it does look like the 50T is towards the banjo. The 30T is obscuring part of the larger 50T

…

It sure is; that's an amazingly misleading image. Who said the camera never lies?

I'm in sackcloth and ashes. Again.

Dave

[JourneymanParticipant @journeyman]

Posted by Mark P. on 23/09/2017 16:39:04:
I am thinking about making a new shorter banjo when I have a bit of spare time.
Mark P.

Yes, that would be useful but I wouldn't try to shorten the one provided as if you cut the end off the legs will likely spring apart. To a certain extent the existing one willl probably work for most things and with a bit of a tweak to the gear sizes will work for everything.

Only goes to show that no-one at the factory ever tried all the set-ups on the headstock plate but just used a calculator. I think the charts in the manual and on the headstock are pretty iffy anyway. Having found one error, I will definitely check for any new set-ups before cutting.

John

[SillyOldDufferModerator @sillyoldduffer]

Posted by Journeyman on 23/09/2017 17:07:13:

Posted by Mark P. on 23/09/2017 16:39:04:
I am thinking about making a new shorter banjo when I have a bit of spare time.
Mark P.

…

Only goes to show that no-one at the factory ever tried all the set-ups on the headstock plate …

John

The same can probably said of lathe owners too! As no-one replied from direct experience, the answers to Mark's question suggest that not many metric WM250 owners cut 20tpi or 26tpi threads.

Thinking about it I've only screw-cut 4 or 5 different pitches on my lathe in the last year. I do far more threading with dies than my lathe. If that's typical, it's no wonder chart errors pass unnoticed.

Dave

[Mark P.Participant @markp]

Dave, same you I think I’ve only screwcut on my lathe a small handfull of times in 10 years I normally use a tailstock die holder. I only needed to cut the 20TPI 1″dia thread to make a puller to remove the clutch hub on my 57 Triumph Thunderbird.
Mark P.

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