PM1127 -low or high gear?

[Pcmaker]

Should I keep the speed at low or high? Right now, I got it on High, 350 to over 2000 rpm

The low is 80 to 350.

Which should I keep on default?

I seem to get a better finish at 1k rpm, but you can hear the motor struggling with torque at lower RPMs around 350

 

[ttabbal]

I usually use HSS, and with Carbide I usually don't mind going slower. So I run low most of the time. Unless I have a real need, I don't bother to switch.

I do wish low could go a little faster sometimes, but everything is a tradeoff.

 

[Pcmaker]

Belt changing is confusing. The belt groove doesn't line up with the "low" setting, unless I'm looking at the wrong thing.

 

[darkzero]

I keep my PM1236 in the low range. 65 rpm is the lowest & 100 rpm for high. I prefer the low for times I'm single pointing a very coarse thread or drilling a large hole. I could get by with 100 rpm for threading but sometimes 65 rpm still isn't slow enough for drilling large holes.

I've been trying to stay away from S&D drills, maybe I should try out the high range. I don't think I've actually every tried high range before.

 

[mikey]

Should I keep the speed at low or high?

I vote for whatever range is appropriate for the size and material of the work piece and the tooling in use. If that requires a belt position change then get used to doing it. Really.

If you're a newbie then you are likely going to work on smaller, softer stuff with carbide insert tooling. Just guessing. If so, then you will be running mostly in high range. But if you mess with HSS tools or turn larger or harder stuff then you have to run at lower speeds so you change belt positions. No biggie.

You guys are blessed with variable speed and it only requires a simple belt position change to use it fully. If it was me, I would get used to changing belt positions. If there is something about it that makes it difficult, I would fix or mod it so it works well and is easy to do.

My lathe has a two speed motor. One switch doubles or halves the speed and I love it but I would love a variable speed set up even more.

 

[Titanium Knurler]

I have a PM 1236-T and also have A and B belt settings. There are twelve speeds but a lot of overlap between the two belt positions. I have been working on some titanium so I keep mine in the A or high range most of the time because that is where the speeds are that I need. Belt changes are pretty easy on my lathe so I don’t hesitate to change over to match what you need. My machine came with a set screw to release the motor position. I replaced it with a knob which makes belt changes a bit easier.

One other thing to consider is noise and vibration. I used a vibration meter and dB meter to check the these things at various belt settings and found that at similar settings the machine was louder and had more vibration in the A belt positions:

Hope that helps.

 

[MSD0]

i keep mine in high 90% of the time, but most of my parts are small in diameter. The pulleys should be inline with each other.

 

[MSD0]

Belt changing is confusing. The belt groove doesn't line up with the "low" setting, unless I'm looking at the wrong thing.

Can you take a picture? The pulleys should be inline with each other.

 

[Pcmaker]

I figured out the belt change system. I put it to low, as if I'm turning on high, it throws so much hot chips at me, that I gotta stand back a few feet from the machine. So now, I have it at around 370 RPM on the low gear, which is the highest RPM for it. I've been turning 1" 1018 cold rolled steel using the "B" setting on the auto feed, which is the fastest.