[How do I?] Which Lathe Setting for Finest Feed

Hi MKSJ
Thanks a stack for that beautiful comprehensive Manual. What a world of a difference in comparison to mine, which is quite old anyway. Will make a hardcopy and study it thoroughly as there's lots there worth revising and learning from.
And will go down on the morrow to ascertain exactly what Numbered Teeth Gearing is installed and the additionals that came with the machine. Will also check our Oil levels and maybe do a change there as well, 'cos it has not been changed since getting the Lathe.
Like I mentioned earlier, there seems to be no "Meshing" at all in the "W" Settings no matter what I tried, and hopefully it ought to be the Gear U referring to, IA.
Much appreciate the time and trouble U so kindly took to post that copy of the Manual. I was really chuffed to receive such an instructional version.
It will indeed come into good use.
Warm Regards
LORD Bless
ATB
aRM
 
Not a problem, please review the manual carefully. They indicate that the lathe must be in the neutral "I" gear position to change the gears, they also say to bump the jog. If running, it must be in neutral under 500 rpm. I am not familiar with this lathe, but sometimes it is hard to get the gears to mesh. If all the 1-8 gears do not mesh, then it may be a problem with the W gear. There are forked shifters and rods, sometimes something gets bent or needs alignment. Do not force anything.
 
"What setting on my lathe would I use to achieve the slowest Finest Feed for Finish Turning."
I hope this does not come across sounding stupid: "What is the purpose of your question?"
Are you just trying to understand the various levers and settings of your machine? Is your goal to machine directly to a good surface finish (no polishing step)?

You do understand that a very fine feed rate does not necessarily produce a nice finish (in fact, quite the opposite). My finest feed rate is 0.0015" per rev - I very rarely ever use that feed rate (for finishing I'm generally about 3x that, but there are many other factors that go into cutting to a good surface finish).
 
Not a problem, please review the manual carefully. They indicate that the lathe must be in the neutral "I" gear position to change the gears, they also say to bump the jog. If running, it must be in neutral under 500 rpm. I am not familiar with this lathe, but sometimes it is hard to get the gears to mesh. If all the 1-8 gears do not mesh, then it may be a problem with the W gear. There are forked shifters and rods, sometimes something gets bent or needs alignment. Do not force anything.
"Tis now becoming all the more obvious that there definitely is a gear problem with my Machine. I omitted to mention that we could not cut 1.5 mm Threads previously as we also encountered a problem with the Long Numbered Lever. We will now have to, perforce open some of the covers and look into ascertaining the issue, from our limited experience with these things. Alternately, we would have to get professional assistance.
Thanks again for the guiding response.
ATB
aRM
 
"What setting on my lathe would I use to achieve the slowest Finest Feed for Finish Turning."
I hope this does not come across sounding stupid:

"What is the purpose of your question?"
Are you just trying to understand the various levers and settings of your machine? Is your goal to machine directly to a good surface finish (no polishing step)?
You do understand that a very fine feed rate does not necessarily produce a nice finish (in fact, quite the opposite). My finest feed rate is 0.0015" per rev - I very rarely ever use that feed rate (for finishing I'm generally about 3x that, but there are many other factors that go into cutting to a good surface finish).

Hello there, Sire.
Yes, indeed. We need to thoroughly know our machine together with its capabilities and or limitations to achieve the finest results possible. Yes again, we have been doing Polishing and would not give up that step at all from the beautiful results obtained.

However, without using our machine to its maximum, we would not know what results would at all be possible. We would not disagree with your kind self on Feed rates. Nevertheless, we may mention that ours is a robust machine indeed on which we have literally burnt HSS Cutters and restrict ourselves to Carbide Inserts only. Again, this maybe our total lack of knowledge on Speeds, which we cannot argue on. The truth of the matter is just that we have been watching numerous You Tube Machinists and are blown away by the beautiful finishes obtained with most using Inserts on big machines similar to ours. Without actually trying this out on my Lathe, I really would not know what the difference would be.

And now because of this new adventure, it has surfaced that we indeed have a problem with our machine that needs attention, which we really hope is not too serious to drastically affect our pocket at this point in our lives, IA.

I sincerely hope this has not come across any more pedantic nor brash than it is, and You would literally take it at its surface value.
Thank You Sir, for taking the time to respond and affording us an opportunity of a totally different perspective.
Much appreciated
ATB
aRM
 
I looked up your machine C6241 - it looks like a pretty standard 16" industrial machine (around here it is branded "Modern" but it is likely sold under a number of brand names). I'm not really understanding the comment about issues with HSS tooling - there is no reason HSS won't work fine. Burning up HSS tooling is an operating issue. Of course carbide can handle higher temperatures and harder materials. Carbide has real down sides too, it is not as keen an edge, there is more tool push, there is less back rake and it is prone to chipping (less forgiving). HSS is a great product, properly applied you can get an excellent surface finish (in fact that would be one reason to use HSS instead of carbide).

Most any material will finish out to a nice surface, but some are much easier to get a good surface than other materials. There are many resources available to recommend the starting point for speeds, feeds and depth of cut. Use about 75% of the recommended value as a starting point. Then, use your roughing cuts to figure out good speeds and feeds to get a nice finish. When you have about 0.03" to go, figure out the depth of cut so your last 3 passes will be the same (i.e. say 0.010" each). Of course, take a measurement after each pass and adjust as needed. The point here is that trying to take a cut of 0.001" depth is difficult to achieve a good finish - especially when using carbide (with HSS you can often get away with a lighter cut - because of the keener edge, more back rake and less tool push).

Let us know how you make out. David
 
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Have you tried a spring cut ?? IE, when you get to the end of the cut put it in reverse and go back without changing the DOC...
**G**
 
- there is no reason HSS won't work fine. Burning up HSS tooling is an operating issue. HSS is a great product, properly applied you can get an excellent surface finish (in fact that would be one reason to use HSS instead of carbide).

When you have about 0.03" to go, figure out the depth of cut so your last 3 passes will be the same (i.e. say 0.010" each). Of course, take a measurement after each pass and adjust as needed. The point here is that trying to take a cut of 0.001" depth is difficult to achieve a good finish - especially when using carbide (with HSS you can often get away with a lighter cut - because of the keener edge, more back rake and less tool push).

Let us know how you make out. David[/QUOTE]

Hello David
As I see it, one of the main problems for me as a novice to Machining is the total lack of experience with correctly Sharpening HSS Cutters, combined with, as U have correctly stated above, having "operating Issues". Being frustrated with the poor quality of edges obtained, HSS was quickly abandoned as an easy alternative to Carbide, which was available in numerous configurations to suit. It's just circumstantial that we have not had access to some practical tuition or guidance in this major side of Cutting Technology. "Tis only of recent that we have seen the You Tube community grow by leaps and bounds where these "Creators" show and share their experiences in all these aspects. Reading all the books in the world has not really helped without the practical demonstrations. On retrospect, methinks it is a bit late into machining for us (to go Back) and start to learn proper HSS Sharpening. But then I guess, that's what "Back to the Future" is all about.

That is a very good suggestion of Yours to try 3 Passes of the remaining 0.76mm of Cut. We will definitely give this a shot and let U know in this regard.

For now we have to tackle our Gear Feed problems with our machine, which we are dreading, as we need to open the covers and try to ascertain the cause with the little background and knowledge of these things, which we have. Oh Well, that's another issue, so here goes .....
Thanks again for the kind response.
Much appreciated
ATB
aRM
 
Have you tried a spring cut ?? IE, when you get to the end of the cut put it in reverse and go back without changing the DOC...
**G**
Hello Sir "G"
Yes Sir. We are indeed familiar with and have heard that word numerous times in threading as well. I'd say it's origination is more American than other worldly. Mind You, we don't recall trying it out for Finish Cuts on the Lathe though. Been using it often on the Mill surprisingly. It's makes much sense and is also a very good suggestion on Your part.
Thank You kindly for the good prompting
LORD Bless
aRM
 
Hello MKSJ
Another silly but quick Q please ..........
How do I remove the covers for the Emergency Stop Button(RED) and the others in that line
Need to open and look into the Gear non-Meshing problem
TIA
ATB
aRM
 
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