New guy with questions. Craftman 6" lathe

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chiefpeyotecoyote
Posts: 12
Joined: Fri Jun 02, 2017 8:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by chiefpeyotecoyote »

Hey,

Thanks for the picture. Thats awesome! Looks like you were cutting on a piece of mild steel maybe? Ive been wondering what the capabilities of this little machine are. All about speeds and feeds. Mine only goes up to 465 RPM and the feed only ranges from .003-.007. makes me wonder what i can get away with on it. pretty much just have to do everything nice and slow.

As far as the belt goes there seems to be enough slop in the belt that it doesnt get hot at all when its running. or show signs of getting worn. So im thinking just run it with what i got til the belts gives up.
John Hasler
Posts: 1852
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: New guy with questions. Craftman 6" lathe

Post by John Hasler »

You don't have the change gears? BTW here's a manual:

http://vintagemachinery.org/pubs/222/1924.pdf
chiefpeyotecoyote
Posts: 12
Joined: Fri Jun 02, 2017 8:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by chiefpeyotecoyote »

Im pretty excited about this little lathe. I just bought a tooling package from little machine shop. comes with QCTP ,holders, tools, drill chuck and some other stuff. Idk about what the quality will be but im sure it will work fine. Im a machinist by trade so all the manual lathes i have run have had QCTP on the them. so i dont even know how to work the rocker tool post right. and in fact it just kinda confuses me. im not sure how you go about getting the tool geometry right if that makes sense.

I appreciate all the help so far everyone. Very awesome.
chiefpeyotecoyote
Posts: 12
Joined: Fri Jun 02, 2017 8:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by chiefpeyotecoyote »

I have the change gears. And i have the manual thank you for the attachment thought. Cant say i understand everything in it but if im understanding correctly you will either have a direct cone drive or a back gear drive. the direct cone goes from380-3050 RPM and the back gear goes from 55-465 RPM. The thread chart mounted on the machine tells you the combination of gears to use to get different threads as well as different feeds. which range from .003-.007. Thats just how im interpreting it but i could be completely wrong
John Hasler
Posts: 1852
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: New guy with questions. Craftman 6" lathe

Post by John Hasler »

Threads and feeds are the same thing. 20 TPI equals a feed of .050".
chiefpeyotecoyote
Posts: 12
Joined: Fri Jun 02, 2017 8:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by chiefpeyotecoyote »

I should have probably known that. Makes sense.
chiefpeyotecoyote
Posts: 12
Joined: Fri Jun 02, 2017 8:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by chiefpeyotecoyote »

since we were talking about it i went through the manual again and didnt find anything so i went out and started playing around with the lathe and found a pin on the backgear that can be pushed in/out of the spindle pulley which engage/disengages the direct cone drive. i feel like a dummy cause that was simple. but im not sure why i didnt see it in the manual how to change that. if im even right
choprboy
Posts: 322
Joined: Sat Oct 29, 2011 11:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by choprboy »

Yes, as you and others noted, you have both direct drive and backgear. In direct drive the spindle bull backgear pin is locked to the spindle pulley and the backgear lever is disengaged. To engage the back gear you pop that pin out to the release position and then pull the lever on the back right corner to engage the backgear spindle. That little pin with probably bug the cap out of you as it rattles, you adjust it just so, come back a week later and it rattles again... Just don't lose the tiny little spring and bb behind the set screw when adjusting/removing for cleaning. It and the oiling set screws will probably fall down in the base between the legs and you'll spend 10min trying to dig it out of the blind corner with all the little chips back there too.

Since there is only a single worm, your threading and longitudinal feed are the same. Thru different gearing you go go from something like 0.0006 to 0.1", but don't remember exactly, my manuals were the original hardcopy and are currently with the lathe at a family member's house. The manual I had was a lot more pages then that PDF I think, I will have see about getting it back to scan.

I seem to remember I typically ran something like ~0.0025 feed when cutting. Usually ran in backgear at 100-200rpm with HSS hogging around 0.020" depth. Then kicked up in the 1100-1300rpm range with carbide and a couple thou for finishing cuts. Carbide was generally hard to run for anything but light cuts though due to lack of drive power and lack of rigidity in the lantern toolpost (easy to bury the carbide and stop the spindle, or chatter in cutting, breaking the carbide tip).

The prior picture was turning a chunk of cast iron for an adapter on a compressor shaft. But I had also turned a bunch of mild steel, as well as some stainless, brass, and aluminum. You can see some turned steel pins and washers from my engine hoist thread: http://chaski.org/homemachinist/viewtopic.php?t=98924

As well some other stuff, the finished compressor adapter (remade in 1018, had problems with the taper fit and screwed up the original part after too many attempts):
IMG_2193s.JPG
Some aligning plug form something-er-other out of 1018, I don;t remember. Live chips flying:
IMG_2205s.JPG
A block of 1018 that was going to be a quick-change tool holder, never finished it before moving to a bigger lathe.
img_0768s.jpg
chiefpeyotecoyote
Posts: 12
Joined: Fri Jun 02, 2017 8:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by chiefpeyotecoyote »

Its funny this little lathe is far more complicated to operate that most every other manual lathe ive ran. all the other ones you just change levers easy cheesy. this one is alot more involved. which i think is awesome makes it a bit more fun. im excited to turn some parts on this thing. just waiting on some tooing.

I appreciate all the help everyone. Ill make sure to put up some pictures from my first project
spro
Posts: 8016
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: New guy with questions. Craftman 6" lathe

Post by spro »

It is more fun and a learning experience which stays with you. The concepts about centered tooling and why they would "dig into" the work makes one explore the angles and sharpness more closely. It often comes down to the orientation of the older lamp post tooling and how that was set. By this knowledge, don't throw away the lamp post or tool holders, for there will be times when only they work. Reaching around the other side of a plate or going very close to tail center. Depending upon the axis of the mounting, how the cutting tool is presented means a lot.
Many of us have seen or bought old machinists' chests and one or more drawer was bits or cutting tools. They fit those different Armstrong LH,RH tool holders and the original owner (unless it was loaded with junk, afterward) knew which one fit the holders for similar work.
Not saying that tool chests were normal for 6" lathes, only the concepts remain.
chiefpeyotecoyote
Posts: 12
Joined: Fri Jun 02, 2017 8:23 pm

Re: New guy with questions. Craftman 6" lathe

Post by chiefpeyotecoyote »

I am interested in learning how to use the lamp tool post. definently new to me. im used to a QCTP which every other manual lathe and even some CNC machines have. but i do have some information on that style of tool post in one of my machinist reference books. it tells you the different geometry of different cutters and how to grind them. just waiting on some HSS to grind into some cutters.
spro
Posts: 8016
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: New guy with questions. Craftman 6" lathe

Post by spro »

Lamp post, rocker style tool posts are very old news now but we weren't there when they were used. Unlike the QCTPs now, there was a balance between the included angle of the holder itself, the rocker positioning of how the holder was held, to what extension of the cutting tool and what shape or which direction. It was like a few confusing things but nothing like today. After some familiarity you get the concepts and they work with proper ground angles.
I'm not saying go back ages, yet problems with newer relate to the shortcomings before. With a lamppost you rarely had the tool holder fit tightly, so the holder was biased against the inside, for that direction of cut. While setting this, the tool holder was chosen to not "spring forward" during the cut and then the proper bit/ cutting tool to be on center. It was very adjustable situation but the guys who use them, leave some things loose, Adjust most and know what bit will work for that situation. Then there are the preangled bits which need a slight grind at most, to achieve the perfect approach.
Pre angled or previously ground 1/4"-5/16" Rex AAA and others with some length to them, are good candidates for getting many cheap. Perhaps that already happened. Minor dressing because they were used the same way. It makes no sense to have a larger toolholder than the smaller 00 size because the angle is more acute and doesn't allow you to go where these small lathes excel.
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