Thread: Sieg C6 lathe new threading capabilities

When there are 2 gears on the first shaft (at the top of the banjo) the gear meshing with the spindle must have a diameter 6mm larger than the gear next to it otherwise the gear will foul the spindle.

Ian,

The gear set at the top of the banjo should be meshing with the fixed 40tooth idler gear which meshes with the spindle, not the spindle directly.
This gear should have enough clearance to allow slightly larger gears in the second position than in the first position, although it may rub on the side of the second gear due to its width.

Meshing directly with the spindle will give you left-hand threads...

Andrew

Gentlemen,
there seems to be a problem with the forum today. I'm receiving email notifications but nothing is posted.

Andrew/Graham, thanx so much for your help. Am working through Andrew's contribution, but Graham's - due to the computer program parameters - have great potential.

Graham, am having trouble with 5.0mm, 5.5mm, 5tpi, 6, 7, 9, 11.5, 12, 14, 19 and 27. My own and Andrew's either don't fit or have too much error. Is there any chance of you adding these to your previous combos?

Regarding the limitations of the C6 leadscrew, I have threaded 5mm and 5 tpi (almost the same thing) without any trouble. Can't detect any problems with strain on the lathe.

I'm assuming if there was a problem it would manifest itself as tightness, inability to turn, or noise.

Kind regards. Ian

Sorry Guys,

wrong forum. Graham is on an English one. He has a computer program which permits entry of the physical set up of the lathe to make the generated combos more effective.

I'm trying to get details of it. We could all use it I'm sure. Whadyareckon?

Regards. Ian

There is a program in this forum some where.
Lathe Gears V1.2.0.0 by Vernon Van D
That might be able to do what you want.
If you cant find it I'll have a look for it later.
Must run

Stuart

OK Ian...

I have tested some pitches above that you were having trouble with for fit on my C6:

5.0mm as per the chart installed fine.
5.5TPI - use gears 33, 80, 42 using the simple gear layout. This will be as accurate as the other imperial threads on the chart. Tested for fit OK.
5TPI as per the chart installed fine.
6TPI - further testing of combinations required for most accurate working setup.
7TPI - further testing of combinations required for most accurate working setup.
9TPI - further testing of combinations required for most accurate working setup.
12TPI - use gears 40, 50, 90, 80, 42 in the compound gear setup, and also use the Sieg reversing idler in place of the standard idler for more clearance.
14TPI - use gears as per the chart, and also use the Sieg reversing idler in place of the standard idler for more clearance.
19TPI - use gears 80, 90, 70, 52, 50 in the compound gear setup.
27TPI - further testing of combinations required for most accurate working setup.

I am also looking into making a new idler for the standard spindle idler position (using the reversed thread cutting mounting position) that will take one of the unused gears for a given gear train and provide more spindle meshing versatility for unusually sized gear setups.
More on this when I have nutted it out.

Andrew.

Boy you sure have been busy. Hope I'm not wasting your time.

Thanx Andrew

Not wasting my time... I'm sure the information will be useful to someone or myself one day.

Andrew

Hi Andrew,

with your help and that of Graham in England I have found near-perfect threads in all metric sizes needed.
I'm going to start on the imperial if ever the weather lets up on me. It's been over 40 degrees C. in my shed.

Graham sent me EVERY thread combo possible with the C6 lathe. Am working through them.

I owe all of you much thanks.

Ian,

Please note that I made a mistake on the last post...the gears that I gave for 5.5mm were actually for 5.5TPI

Andrew

Hi Andrew,

to err is human - to forgive is divine!!

I've made so many boo-boos lately. Age? Alzheimers? Booze? Stress? Too busy? I dunno!

Probably all of 'em.

How's this heat mate?

Ian,

I blame the heat... probably about 40C in the workshop, and I'm silly enough to be making up an adjustable idler mounting plate and shaft as described in a previous post.
Mock-ups so far are looking good to allow several gear combinations to be used that would not fit before with the standard Sieg supplied spindle idler.

Watch this space....

Andrew

Ian,

Check out this thread https://www.woodworkforums.com/f65/yo...ml#post1743732 for the adjustable idler gear mounting for the C6.

Having just installed it, and using the 66T gear as the idler, with about 10 minutes fiddling I have been able to get an accurate and workable 6TPI pitch combination (6.001 TPI) using 42, 80 , 30, 75, 90 gears. This combination is only possible with a large idler gear to provide clearance at the spindle end of the banjo.

This looks promising for many other normally unworkable combinations and pitches.

Andrew.

More info...

With the adjustable idler setup, for RH threads idler size can be anything from 40T to 90T, and the smallest that works for the particular combination is best.
Using the standard reversing idler for LH threads, the idler can be either 70T, 75T or 80T.

Andrew