How much power does the power feed on a 9A utilize?

I've had times where I'm taking a decent DOC on my 9A, with what feels like a halfway decent feedrate. Try to use the power feed, and the lathe stalls instantly.

I'm sure 80% of this is not realizing what feed rate I have when handfeeding vs power feed, and picking a feed rate that's much higher than what my approximate feed fate was by hand.

But part of it has to be friction losses in the drive train of everything up to the saddle. Does anyone have an approximate idea of how much of your power is consumed?

This is mostly just for the sake of curiosity.

Domodude17 said:

I've had times where I'm taking a decent DOC on my 9A, with what feels like a halfway decent feedrate. Try to use the power feed, and the lathe stalls instantly.

I'm sure 80% of this is not realizing what feed rate I have when handfeeding vs power feed, and picking a feed rate that's much higher than what my approximate feed fate was by hand.

But part of it has to be friction losses in the drive train of everything up to the saddle. Does anyone have an approximate idea of how much of your power is consumed?

This is mostly just for the sake of curiosity.

Click to expand...

Not enough information, but.. two brand-new as of dawn of the 1960's - a SB "toolroom" ten and a Logan both arrived with 3/4 HP 3-Phase motors.

My impression , given either could "chirp" flat belt or Vee... is that 3/4 honest 3-P HP was about all the power a "featherweight" 9" or 10" could put to work "combined loading".

1 HP or more would prolly just slip the belts more often?

By comparison, "nominal" 9" Hendey T&G or 10" Monarch 10EE can use all of their as much as 6 or so HP, given that (at least) their DC motor versions were over-Volted and their drivetrains loaded at only about half their max capacity.

Now ..... if YOUR SB 9........???

.. happens to be running off a 1/3 HP single phase fugitive from a scrapped 1954 wringer clothes warsher?

Yah.

You could stall that!



OTOH? Give her 3/4 honest and true HP, belts in good condition, appropriate speed and feed?

You will likely crash the loyal lightweight from tool or work deflection before you'll stall her valiant little a**.

DAMHIKT!

+1 on not enough info. Your carriage may be binding, which is a very bad thing and needs to be immediately addressed, or your DOC and/or feed rate is too much.

You need to enumerate your original post so that we can possibly help.

Short answer is, yes you are correct - the feeds use substantial power from the motor running the works. Most often realized with heavy cuts at a high feed rate.

1) it's a amall machine. Go easy on it.

2) how does it 'stall?' Motor stops, or the flat belt slips?

Look at it this way.
When feeding by hand, all the motors power is going to turning the spindle to take the cut.
The power to advance the carriage comes from you, the carriage don't advance itself.
Throw in the power feed and you get a break and the motor now has more work to do. Could be the straw that breaks the camel's back.

The answer to your question is variable. The power the carriage feed consumes depends on the feed speed you select. The faster the feed, the more power is consumed. However, by far the major consumer of the available power is the spindle and tool load. It is important to note that the limiting factor is not the motor. It is the flat belt drive. It will not couple more than 3/4 hp at best without slipping. Remember, the machine is shipped with a 1/2 hp motor.

Knowing what feed rate you picked would help a great deal. In my experience, the actual load on the motor from running the gearing for the automatic feed is quite modest. I suspect you picked a feed rate that's just too high for the depth of cut. Ease off a bit!

X2 knowing your actual feeds and speeds is crucial. Also try to use an optimal tool geometry. That is why I switched to CCGT inserts -- much less tool pressure, more of the HP goes into the cut. My machine maxes out with high speeds and feeds. It'll do it, but it obviously won't like it. The only time I've chirped the belt is when that cutoff blade got buried in the piece and dug in, in back gears. I use the Automotive serpentine belt with the ribs on the pulleys, even though the pulleys are smooth.

I have tested this setup and it is possible to stall the 1/2HP motor completely in the higher gears. Lower gears will chirp the belt or break things. Normally the most aggressive cuts I do would be 1mm DOC x .05mm feed -- it hates those cuts. It does do them though. On 1.5" mild steel, at (say) 285 RPM. Dry.

My motor is the original SB/GE motor. Maybe they actually did build things better back then.

The power used in feeding is a small fraction of what goes into cutting.

I have a 16 speed V-belt drive 9A powered by a 1hp Marathon inverter-duty motor.
Even at very low feed rates of .003 IPR or so, I can stall the motor before the belt slips.

Can't speak for the much more common flat belts. Obviously,they can't transfer torque as effectively as a modern V-belt.
If I had flat belt pulleys, I'd try to figger out a way to groove them for a modern serpentine belt. I generally don't push the lathe hard- but I do push it hard enough to run carbide effectively and I have no issues.

I've got a 3ph 3/4hp motor running a serpentine belt. If things stall, it's the belt squealing.

I dont have exact feeds/speeds since this is something that just comes up occasionally-i'm not lamenting over a single instance. I believe most of the issue is just an inexperienced operator, that chump...

Thanks for the input everyone!

Domodude17 said:

I've got a 3ph 3/4hp motor running a serpentine belt. If things stall, it's the belt squealing.

I dont have exact feeds/speeds since this is something that just comes up occasionally-i'm not lamenting over a single instance. I believe most of the issue is just an inexperienced operator, that chump...

Thanks for the input everyone!

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Nah, it's called "learning", so it's OK Every machine has its own personality.

So when I got mine, I decided to find out what the "envelope" was -- what is the maximum, and what is the minimum that it can do. For example, on the other extreme, I can confidently use mine to shave half a thou. With carbide no less. Or hog off a bunch like I said above. Both of those situations will have their own RPM's that they want. They will have their own feed rates.

So it's a good idea to experiment with the entire range of speeds and feeds, and find the "sweet spot" that your machine likes.

three things to much friction due to wear lack of lube or misalignment the drive motor is to small for the job at hand and if its just for feed not threading then how about installing a electric leadscrew drive

I have a 9A and certainly can easily stall the spindle. It's an undermount drive with the segmented vee belt driving the spindle. When I stall it it's the vee belt that slips. The belt has a small amount of oil on it that I periodically wipe down to minimize, so that's half the problem. It has never leaned on the 1/2 hp motor to my knowledge.

Stalling the motor is difficult to ascertain and in the most severe case I imagine you could hear it slowing, I've never detected this, just the belt slipping. Yeah I could put an amp meter on the mains to see just how much I'm leaning on it. Worst case would be it slowing to the point the revs drop and the centrifugal switch goes back to the start switch. But that's right close to the destructive locked rotor scenario.

One thing that hogs power is carbide tooling. The radiused cutting edges require more tool pressure and generally more revs to give a decent finish. These old light duty slow speed machines weren't designed for that. You can hear and feel the feed gear train working harder and needing a lot of power. *But I won't go back to HSS as carbide is so convenient. Even if half the time I can't cut deep enough to get the chip breakers working. For example, on a 4.5 inch chunk of 4140 turning the OD at near maximum revs, I can only buzz off about .015" with carbide. The finish is near big boy pro quality though. With HSS the speed has to be lower but the cut depth can almost double.

All we can do on these old machine designs is oil everything up, tighten the belts and hammer on it as well as the machine can handle it.

edit: Standard OEM 1959 vintage GE 1/2 hp 56 frame 120 volt motor.

chipss said:

One thing that hogs power is carbide tooling. The radiused cutting edges require more tool pressure and generally more revs to give a decent finish. These old light duty slow speed machines weren't designed for that. You can hear and feel the feed gear train working harder and needing a lot of power. *But I won't go back to HSS as carbide is so convenient. Even if half the time I can't cut deep enough to get the chip breakers working. For example, on a 4.5 inch chunk of 4140 turning the OD at near maximum revs, I can only buzz off about .015" with carbide. The finish is near big boy pro quality though. With HSS the speed has to be lower but the cut depth can almost double.

edit: Standard OEM 1959 vintage GE 1/2 hp 56 frame 120 volt motor.

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That's why I tell people to use xxGT carbide instead of the usual CCMT. There is no radius on the edge of a xxGT insert because it is ground dead sharp just like you would HSS. It made all the difference in the world on my machine, it's actually very usable now. The difference was so great, I put all my other carbide in a drawer, and ordered all new xxGT inserts.

The xxGT carbide actually outperforms HSS by a good margin on my machine -- much smoother and easier cutting, less work for the motor. For example, these: RISHET TOOLS CCGX / CCGT 32.51 High Polish Carbide Inserts for Aluminum (10 PCS) | eBay

^ Thanks for the 'high dig in' CCGT tip. Now the confusing effort of what I have vs changing to the CCGT and what size begins, as to an idiot like me it's quite diabolical.

I got some no name brand CCGT inserts for aluminum a while back. No kind of chip breaker on them, but man did they work like a hot damn in aluminum-i couldn't throw material at them fast enough, and on a 9A no less! Only downside was the surface finish wasn't great, but it was tremendous for hogging. I'll have to look into some CCGT inserts for ferrous stuff

Domodude17 said:

I got some no name brand CCGT inserts for aluminum a while back. No kind of chip breaker on them, but man did they work like a hot damn in aluminum-i couldn't throw material at them fast enough, and on a 9A no less! Only downside was the surface finish wasn't great, but it was tremendous for hogging. I'll have to look into some CCGT inserts for ferrous stuff

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Believe it or not, I use the same inserts for everything -- ferrous or nonferrous makes no difference. My SB9 loves those inserts regardless of what I'm turning. The xxGT inserts are meant for aluminum and copper, but they do just fine on steel and alloys.

chipss said:

^ Thanks for the 'high dig in' CCGT tip. Now the confusing effort of what I have vs changing to the CCGT and what size begins, as to an idiot like me it's quite diabolical.

Click to expand...

I'm not a carbide expert, but I think it depends on the shank size of your tools. If you're using 1/2" shank tools with a fat diamond shape insert, chances are its CCGT-3251.