Sieg C6 Lathe new threading possibilities

[Ian HansenParticipant @ianhansen20511]

Hi Steve/John,

supplementary gears for C6 (not available yet) are 28, 32, 36, 48, 54, 56, 58, 64, 68, 72, 96.

Those 11 gears combined with the 16 supplied with the machine (in Australia) give a total of 47 threads. This includes 5 UNM miniatures, which are 0.4, 0.8, 1.0, 1.2 and 1.4mm. I have also spread the extent of the threads from 0.1mm to 5.0mm, and from 257 tpi up to 8 tpi, but the new gears above will allow 7 and I think 6 tpi as well.

Because I have not received supplementary gears yet the 6 and 7 tpi are theoretical, but note that the 5mm thread which I have used is 5tpi. So they turn the Sieg C6 into a very useful machine. I remind users that some of my calculations using the existing gear set are very close to desirable specifications, but with the supplementary set will all be "perfect".

John with your email address, I get the latter part from @ but not the part before.

I will email final gear cards to you asap when I comprehend how to write "addy is john". Sorry to be so dumb.

[Ketan SwaliParticipant @ketanswali79440]

By using the word addy, John means address.

so his address is john [at] stevenson-engineers.co.uk

Ketan at ARC

[Ian HansenParticipant @ianhansen20511]

Hi Ketan, thank you for showing me.

You must be the Ketan at Arc Euro?

John will have the new, revised chart in 3 minutes.

[Ketan SwaliParticipant @ketanswali79440]

Yes, that's me – Ketan at Arc Euro.

Are they going to send the gears to you directly or are they coming in Stevens' next consignment?

Ketan at ARC

[Ian HansenParticipant @ianhansen20511]

Hi Guys,

have held off adding anything to the forum until now. Sieg has informed me they are proceeding to have component suppliers make the accessory gear set. C6 owners should have access through their preferred supplier, but I can't yet say when. I do not yet know if a metallic thread chart will be available.

Re. the gear charts. With my own calculations using the existing gear set, my machine can cut about 47 threads in common use today. But with the additional gears, and Sieg's engineer's spreadsheet, I will be able to cut no less than 51, all quite accurately.

As soon as I can I will post a new chart with the FINAL thread cutting set ups. No doubt the engineer will revise some of my calculations. Not many I hope.

[Ian HansenParticipant @ianhansen20511]

Guys,

you're not going to believe this but – after all the calculating I've done – on the Sieg C6 gearing, I found a person on the web yesterday who had already programmed a computer to do the same thing! His combos are a mix of compound and double reduction, with 2 simple combos. I have checked all the math, and they are all very accurate (like 0.001 mm to 0.006mm). Now I am going to make sure they all physically fit on the machine. You would be aware that computer generated combinations do not take into account physical limitations of the banjo.

Hope to provide you with a FINAL chart soon. By the way, these calculations are for the existing gear set. No additional gears needed!!

Ian

[Graham WhartonParticipant @grahamwharton]

Ian,

Worth noting that some manufacturers ship different sets of change gears

e.g my Axminster C6B didnt come with a 55 tooth gear.

The standard set in mine was

25,30,33,40,42,50,52,60,66,70,75,80,80,90,90

Ontop of that I made the following

25,63,81,84,100,100

This allows me to cut a bewildering array of threads, right down to 0.05mm pitch for fine feed work (although you do have to have the door open as the 100 tooth gear fouls the door when in 0.05mm pitch.

I have a computer program that you provide with the list of changegears, some dimensional information on diameter of spacers, size of banjo and it will basically give you the gear combo with the minimum error for every metric pitch from 0.05 to 3.0mm in 0.05mm increments and every imperial pitch from 8 to 80 TPI (although actually these can be expanded if need be). This program helped me alot when defining my new threading charts once I had made my extra gears, unfortunately to adjust the values requires a certain knowledge of C++ programming and the ability to recompile programs. However if you give me your list of change gears I dont mind sending you the output for you to verify your combinations.

[Graham WhartonParticipant @grahamwharton]

Posted by John Stevenson on 08/12/2013 21:37:26:

Decided to program Ian's chart to do a machine chart.

John,

I think you have a couple of the columns the wrong way round.

Graham

[Graham WhartonParticipant @grahamwharton]

Ian,

Heres some proposed mods. Not guaranteeing they will fit on the banjo, but worth checking. The software that I used to generate them does take into account geospacial limitations, but may not get it right in every case. Ive just used your standard set of gears taken from your tables.

Note in the gear listing below a : means on the same shaft. a – means teeth are meshing. The first 40 is the spindle shaft gear and the last gear is the leadscrew gear.

Heres some more metric threads and some corrections

0.2mm – 40-70:30-90:42-80 – 0% error
0.25mm – 40-75:50-80:30-80 – 0% error
0.3mm – 40-70:40-80:42-80 – 0% error
0.35mm – 40-80:70-75:30-80 – 0% error
0.45mm – 40-70:60-80:42-80 – 0% error
0.55mm – 40-80:66-60:40-80 – 0% error
0.65mm – 40-80:52-66-80 – 0% error
0.75mm – 40-80:75-60:42-70 – 0% error
0.9mm – 40-70:75-50:42-80 – 0% error
1.1mm – 40-80:66-80-60 – 0% error
1.2mm – 40-80:60-66-50 – 0% error
1.3mm – 40-50:52-80:75-60 – 0% error
1.4mm – 40-80:70-66-50 – 0% error
1.6mm – 40-66-80-50 – 0% error
1.8mm – 40-66-80:90-50 – 0% error
2.2mm – 40-80:66-80-30 – 0% error
2.25mm – 40-66-80:90-40 – 0% error
2.4mm – 40-80:60-80-25 – 0% error
2.8mm – 40-80:70-80-25 – 0% error
3.2mm – 40-66-80-25 – 0% error
3.5mm – 40-80-52:75-33 – 0.099% error. Yours has 2% error
3.6mm – 40-66-80:90-25 – 0% error
4.0mm – 40-80-50:75-30 – 0% error. I Think there is an error in your table for this one.
4.4mm – 40-90-40:66-30 – 0% error
4.5mm – 40-90-50:70-25 – 0.44% error. Best I can do. I Think there is an error in your table for this one.
4.8mm – 40-80-60:90-25 – 0% error

Imperial threads

8TPI – 40-70-80-25 – 0.78% error. Yours had -1.7% error
10TPI – 40-66-60:80-42 – 0.0125% error. Yours had 0.06%
11TPI – 40-75-42:80-66 – 0.0125% error. Yours had 0.06%

12TPI – 40-66:70-80-40 – 0.2147% error. I would check yours. I think the gears train may be too short to mesh with the spindle.
13TPI – 40-80-30:66-90 – 0.0875% error. Yours had 1.7% error
15TPI – 40-50-90:80-42 – 0.0125% error
16TPI – 40-66-42:75-90 – 0.0125% error. Yours had -0.78%
18TPI – 40-80-60:70-66 – 0.2147% error. Yours had 0.79% error
20TPI – 40-75:50-80-42 – 0.0125% error. Yours had 0.06% error
22TPI – 40-66:40-80-42 – 0.0125% error. Yours had 0.06% error
24TPI – 40-66-42:50-90 – 0.0125% error. Yours had -1.22% error
26TPI – 40-52:50-90:80-70 – 0.0125% error. Yours had -0.08% error
28TPI – 40-70:75-42:40-90 – 0.0125% error. Yours had -9.2% error
30TPI – 40-90:80-70:50-60 – 0.0125% error. Yours had 0.74% error
32TPI – 40-70:75-60:50-90 – 0.0125% error. Yours had 0.17% error
36TPI – 40-52:50-90:66-80 – 0.0606% error. Yours had 0.22% error
40TPI – 40-52-70:50-90 – 0.0125% error. Yours had 0.06% error
44TPI – 40-90:75-70:40-66 – 0.0125% error. Yours had 0.06% error
48TPI – 40-90:80-42:25-80 – 0.0125% error. I think there is an error in yours
56TPI – 40-60:66-80:33-80 – 0.0394% error
60TPI – 40-90:80-60:25-70 – 0.0125% error
64TPI – 40-90:75-60:25-70 – 0.0125% error
72TPI – 40-80:66-52:25-90 – 0.0606% error
80TPI – 40-90:80-70:25-80 – 0.0125% error

Hope this is of some use, maybe get some of your errors down on the imperial threads and fill in some unusual blanks.

Graham

Edited By Graham Wharton on 29/01/2014 22:43:37

[Graham WhartonParticipant @grahamwharton]

Forgot to say,

I was assuming that the limitations on my C6B are the same as yours, i.e the banjo is the same size etc.

The limitations/assumptions i have in place for the software to give me those recommendations are

• Leadscrew pitch is 2mm
• Fixed gear on spindle is 40 teeth
• Mod 1 gears
• Distance from spindle axis to leadscrew axis is 174mm
• The distance from the leadscrew axis to the axis of the bottom gear shaft on the banjo cannot be less than 80mm
• The distance from the leadscrew axis to the axis of the top gear shaft on the banjo must be less than 150mm
• The clearance between two gears positioned on adjacent shafts, but not meshing should be at least 6mm. (when measured using pitch diameter…. The actual gap between teeth will be smaller than 6)
• The diameter of a spacer is 22mm
• The first gear (the one that meshes with the spindle gear) must have more than 50 teeth or the banjo will foul on the spindle.
• When there are two gears on the 1st shaft (top of the banjo) the gear meshing with the spindle must have a diameter 6mm larger than the gear next to it on the shaft, otherwise the gear will foul with the spindle.
• There are no checks made that the gears do not foul on the door.

If anyone wants the software, and can handle the code hacking, please let me know and I will provide a copy.

 

Graham

 

 

Edited By Graham Wharton on 29/01/2014 22:38:09

Edited By Graham Wharton on 29/01/2014 22:39:21

[John Stevenson 1Participant @johnstevenson1]

Sorry to nit pick but 19 and 27 are a must for pipe threads

they often list 11 1/2 as well but to be honest in all my time I have never come across it.

[Graham WhartonParticipant @grahamwharton]

The threads I posted above were just additions where Ian was missing a thread, or where I could improve on his accuracy.

I can improve on the accuracy of the 27TPI thread after relooking

27TPI – 40-52:50-90:66-60- – 0.06% error

And while were at it, Ive just modded my software to include half TPI threads

11-1/2TPI – 40-66:60-80-33 = 11.525TPI = 0.2191% error (although this configuration is close on the "When there are two gears on the 1st shaft (top of the banjo) the gear meshing with the spindle must have a diameter 6mm larger than the gear next to it on the shaft, otherwise the gear will foul with the spindle." rule.)

Graham

Edited By Graham Wharton on 29/01/2014 23:08:19

[Ian HansenParticipant @ianhansen20511]

Wow Graham, you've given me a lot to work on. I'll be seeing star …er gears, in front of my eyes!

The computer program I told you about yesterday – well, of the first 15 combos I checked for fit and useability on the C6, 13 did not fit. The danger with computer generated stuff is that people don't check the fits before publishing.

Graham, my C6 does not have a 55 toothed gear either – they are the same as yours. I've written out so many charts little boo boos creep in and sit, waiting to be discovered!

Sieg has decided NOT to go ahead with manufacturing supplementary gears because of commercial reasons- like, not enough people will purchase them.

Thanx everyone for your input. Very much appreciated. Ian

[Ian HansenParticipant @ianhansen20511]

Guys, the "rule" for the C6 –

Where there are 2 gears at the top of the banjo, the gear meshing with the spindle must have a diameter at least 6mm larger than the gear next to it otherwise the gear will foul the spindle.

Hope this helps in determining fit without messy hands!!!!!

[Ady1Participant @ady1]

Chaps

I've already done a program for a basic threading scenario

**LINK**

It's in TPI, think TPI, not mm

25 change wheels allowed

You can even state your max allowable error

 

Edited By Ady1 on 30/01/2014 02:16:51

[Graham WhartonParticipant @grahamwharton]

Posted by Ian Hansen on 30/01/2014 02:12:32:

Guys, the "rule" for the C6 –

Where there are 2 gears at the top of the banjo, the gear meshing with the spindle must have a diameter at least 6mm larger than the gear next to it otherwise the gear will foul the spindle.

Hope this helps in determining fit without messy hands!!!!!

Actually, I went back and looked at that rule, and looking at my machine, that makes no sense to me now as there is plenty of room as the banjo gear set does not mesh directly with the spindle, but with the intermediate gear that sits permanently engaged just below it.

[Graham WhartonParticipant @grahamwharton]

Posted by Ian Hansen on 30/01/2014 01:50:25:

The computer program I told you about yesterday – well, of the first 15 combos I checked for fit and useability on the C6, 13 did not fit. The danger with computer generated stuff is that people don't check the fits before publishing.

Yeah, I know this is some times not helpful. Please take all of the suggestions that I have given you as untested and unknown to work. However, as I said the program does take into account the space available. I generated a full new chart for mine with my extended set of gears and sofar every one that I have tried fits perfectly.

[Ian HansenParticipant @ianhansen20511]

Hi Graham,

any chance of combos for the following "gaps" in your list:

5.0mm, 5.5mm and 5, 6, 7, 9, 11.5, 12, 14, 19, and 27 tpi? With the original gear set supplied by Sieg.

Your computer program seems to generate more effective combos that actually fit. Is it commercially available?

Would love a copy. Regards Ian.

[Graham WhartonParticipant @grahamwharton]

5.0mm – 40-90-40:75-30. Error 0%

5.5mm – Best I can get is 5.538mm which is 40-75-52:90-25. This is 0.6993% error

5 TPI – 40-80-42:80-30. 5.001TPI Error 0.0125%

6 TPI – 40-90-33:70-40. 5.987TPI Error 0.2147

7 TPI – 40-80-60:90-33. 6.985TPI Error 0.2147

9 TPI – 40-80-30:70-66. 8.981TPI Error 0.2147

11.5 TPI – 40-66:60-80-33. 11.525TPI Error 0.2191%

12 TPI – 40-66:70-80-40. 11.974TPI Error 0.2147%

14 TPI – 40-80-60:90-66. 13.970TPI Error 0.2147%

19 TPI – 40-66-80-60. 19.050TPI Error 0.2625%

27 TPI – 40-52:50-90:66-60. 27.016TPI Error 0.0606%

Hope this helps.

Edited By Graham Wharton on 31/01/2014 07:09:03

[Graham WhartonParticipant @grahamwharton]

Ian,

If you PM me your email address, I will email you the full output from the program, which is gear combinations for all metric pitches from 0.01 to 5.5mm in 0.05mm increments and TPIs from 5 to 80 in 1/2TPI increments for the standard gear set. There are no limits on the errors in the output, so it will give you an output even though it gets no-where near the right number, but it does tell you how close it got, and what the error% is so you can make up your own mind if the combination is good enough or not.

Graham

[Ian HansenParticipant @ianhansen20511]

Fabulous Graham.

What would I do without you?!!

Kindest regards. Ian

[Ian HansenParticipant @ianhansen20511]

Hi All,

have finished checking fit and thread cut on all Graham's metric combos. They all work great. His computer program really makes a difference. Now I have every thread in common use today from 0.1mm up to 5.0mm.

When it's not over 40 degrees C. in my shed I'll start on the imperials! How I envy English weather!!!

Australia is getting so hot. It was 48 deg. C on Black Saturday. Where will it end I wonder?

[mahgniaParticipant @mahgnia]

Gentlemen,

My first post on this forum.

Please check out this link (**LINK**) on the Australian Metalwork Forum showing a simple modification to the C6 spindle idler setup that greatly increases the number of gear combinations that can be used, as it eliminates the clearance problem between the quadrant/banjo/first gear cluster and the standard 40T idler gear under the spindle. It also allows the first gear in the top cluster to be much smaller than the second gear in that cluster.

I will need to experiment with left hand thread setups to check if the modification can be used there also.

Andrew.

[Ian HansenParticipant @ianhansen20511]

Hi All C6 guys,

well – I have just finished checking all 55 threads. They all work beautifully and get this chaps – they are all with the ORIGINAL set of 16 gears supplied by Sieg. No extras at all. No modification of the banjo necessary.

This has come about as a result of a collaborative effort from Graham, Andrew and myself. I only wish I saw this website 2 years ago. It would have saved me literally months of work.

I am preparing the final printed gear chart and will post it very soon. Range is mm, 0.1 and 0.2 for turning, up to 5mm for threading, and 5tpi up to 80 tpi, 55 in all.

I must thank Graham, Andrew and the forum developer/originator for making this all possible. When I purchased my C6 lathe, I was disappointed that it would not turn certain threads I needed, like 28tpi. If only I knew.

Now you guys are very smart indeed. Tell me why Sieg needs to produce a C6 with an imperial leadscrew which needs gears like 127 teeth to make metric threads, when the metric 2mm leadscrew can turn ANY thread? Do not use words like parochialism!!

Check out Sieg's website for their new C8 and C10 lathes. Posting chart soon.

[Ian HansenParticipant @ianhansen20511]

Guys, please find attached ( I hope ) latest – last – final gear chart for turning and threading Sieg C6 lathe.

Tried to ensure no transcription errors. This chart contains the best of Sieg's original, Graham's and my own combos.

Gawd I've forgotten how to attach the chart. I'll play a little bit.

Thanx to everyone who helped.

[Author]

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