What are factors for what "class" of lathe to buy?

[skcncx]

That and parting.

Yea, parting. It's a skill I need to hone (as with everything else lathe related). I read the article @davidpbest provided in a previous post so I have some things to try the next time I'm out in the shop. I think my first issue is setup and alignment, eyeballing it apparently isn't good enough . I've had various rates of success... so I know things can go more smoothly from start to finish with the part actually falling off.

 

[matthewsx]

No doubt, I've been in 6061 aluminum and some mild steel so far... my guess is on stainless DOC becomes less with a smaller machine. The price of material is starting to get frustrating as well... aluminum is crazy... not sure about stainless stuff.



My guess is the PM 1228 is more of a powerful BLDC sewing machine electronic setup (hyper specific for given lathe it's installed) overlapping feature for what's needed on a lathe, variable speed, breaking, reverse direction etc... but nowhere near the durability and configurability of a true VFD setup.

I spent $1500 for a Tecknomotor spindle and 110v Delta VFD on my CNC and have had zero issues since install... I plugged in the port to see all the config options via PC software and realized after 200+ settings... I just closed it and glad it's doing everything I need... like two operations, on/off and speed based on frequency output from my controller card.

I had a used Teknomotor originally on my CNC. Burned it up unfortunately so that’s why I went to the sewing machine motor. Eventually should put a real servo on it but that will have to wait a little longer until I have the new controller going.

Hope you’re getting closer to a decision.

John

 

[Aukai]

For parting, tool height is important, and I use a Noga mounted dial indicator to set the blade exactly perpendicular cranking it in, and out. The 1228 was not as easy to set up for parting. Everything had to be done to make a straight, non chatter cut. The 1340 is not as particular with the Al, and MS, and powers through.

 

[skcncx]

I had a used Teknomotor originally on my CNC. Burned it up unfortunately so that’s why I went to the sewing machine motor.

Well, that's a bummer... I purchased Tecknomotor from DamenCNC who were very helpful... certainly leaps and bounds better than a wood handheld wood router many use on their hobby cnc for woodworking.

Hope you’re getting closer to a decision.

I am, going to sit on it for a day or so... but it's the PM-1228. I think it's the right fit for my use and needs. It's not unlikely it could sit for a couple months between use and then get heavily used for a given couple months. Being I fit all this hobby stuff around work, kids and many other life things it seems the responsible choice. I'll look again for other brands/machines like the Eisen ones but so far all roads have lead me back to PM and their line up, particularly the 1236T and the PM-1228. Maybe I'll stash most of the savings over the 1236T in a starter fund on a mill.

 

[mmcmdl]

To make this simple .........bigger is better if you can afford it . If you plan on owning this lathe for 10 years or so , the price difference is minimal over these years . Your time is worth money also . The extra mass helps with cuts unless you don't mind taking smaller and more cuts per project . IMO , the saying " Buy once , Cry once " is the ticket here . YMMV .

 

[Dabbler]

@Aukai beat me to it. the extra 400 lbs can make a big difference when parting, but I have another quick story to tell:

Bear with me - this is actually relevant..

I was chamfering a 10" pipe for another hobby machinist, Lots of room on my 12" lathe (750 lbs). Used the 3 jaw, and the outside jaws. Thought it would be an easy job. Broke 4 carbide inserts, Wrecked a custom ground HSS 3/8" tool. I finally gave up. The guy I was doing the job for has a 14X40 lathe but far less experience. He chicked a cheap brazed on carbide tool and chamfered it in 10 minutes. I spend an hour and a half, broke 4 high-quality (expensive inserts)... This is because of the difference in rigidity between a 750 lb lathe and a 1500 lb lathe. So yeah, the weight makes a big difference in some cases.

(this is before I got my 1440 working and my 1560 was in pieces).

 

[skcncx]

For parting, tool height is important, and I use a Noga mounted dial indicator to set the blade exactly perpendicular cranking it in, and out. The 2228 was not as easy to set up for parting.

How do you make fine and controlled adjustments to a QCTP for aligning the parting blade? Knowing it's out of alignment with dial indicator is one thing... but on my OXA QCTP... I release tension and tighten back up, but getting ALL movement out when I clamp it back down in the position I want it, there's inevitable movement for turning likely not an issue... but if parting needs to be dead on... that's a challenge.


I have a couple cheap-o magnetic indicator mounts... I have struggled with just mounting indicators to them... maybe I'm missing pieces in what I have. That's one accessory I need to go a little nicer on.

 

[mmcmdl]

Easiest way , mount the holder in the post while loose and bring it up against the chuck and lock it down . The parting tools have clearance so a thou or 2 off means nothing .

 

[skcncx]

Easiest way , mount the holder in the post while loose and bring it up against the chuck and lock it down . The parting tools have clearance so a thou or 2 off means nothing .

Good, well, I did something similar, just the addition of a 1-2-3 block between chuck and already mounted parting tool in QCTP. The 1-2-3 block just to clear the jaws... I'll just have to keep practicing just seems like I always get a some movement once I tighten the QCTP clamping nut.

 

[Just for fun]

I use a 1,2,3 block between the chuck and the tool holder.

-EDIT- You posted same time as I did. I do the same as you.