9A 6speed to 16 speed conversion?

lonestar308 · Jan 31, 2019

Is this doable or even recommended?

I have a 1945 9A 444A that currently has the single speed countershaft, 1/4HP GE motor, and 3 step flat drive pulleys. It's currently completely disassembled for the restoration, and I was pondering if a conversion to 2-speed countershaft/motor pulley + 1/2HP motor + 4 step v-belt drive pulley setup would be possible.

I can find all the parts on ebay...but I wanted to confer with the sages out there before I even started down this road.

Thanks in advance!

iwananew10K · Jan 31, 2019

3ph and VFD solves all, better and cheaper than what you are proposing too.

lonestar308 · Jan 31, 2019

iwananew10K said:
3ph and VFD solves all.

Not quite...you're still limited by the 3-step flat drive pulleys and top motor speed of 1800 rpm...top spindle speed is still 658 rpm...with the 16-speed setup I'd get max spindle of 1290 or so...and they did make them from the factory like this, Cat. #744 9" Model A, 16-Speed, V-belt bench lathe, Horizontal Motor Drive

But yes, I have considered the 3ph/VFD route as well...

iwananew10K · Jan 31, 2019

The higher top speed is a function of the 2 step motor pulley and countershaft...the 16 speed option is no better top speed than the standard 12 speed flat belt and is a very costly PITA.

3ph and VFD can if done right do all the "16 speed" can do and more.

lonestar308 · Jan 31, 2019

iwananew10K said:
The higher top speed is a function of the 2 step motor pulley and countershaft...the 16 speed option is no better top speed than the standard 12 speed flat belt...

Top speed is the same, yes, but you have the option of more intermediate speeds...

iwananew10K said:
...and is a very costly PITA

That's a matter of subjective opinion...I am simply asking if the conversion is doable/possible

iwananew10K · Jan 31, 2019

Sure, you can do it.

I thought you were wanting opinions/alternatives...my bad.

Carry on.

SBLatheman · Jan 31, 2019

lonestar308 said:
Is this doable or even recommended?

I have a 1945 9A 444A that currently has the single speed countershaft, 1/4HP GE motor, and 3 step flat drive pulleys. It's currently completely disassembled for the restoration, and I was pondering if a conversion to 2-speed countershaft/motor pulley + 1/2HP motor + 4 step v-belt drive pulley setup would be possible.

I can find all the parts on ebay...but I wanted to confer with the sages out there before I even started down this road.

Thanks in advance!

FYI; There are 2 different Vee belt cone pulleys for the 9”. The early ones were a little smaller in diameter to clear the inside of the headstock and to allow belt changes.
I have both sizes available.

Ted
[email protected]

lonestar308 · Jan 31, 2019

Maybe a combo of the 2 options....

This...https://dealerselectric.com/item.asp?cID=2&PID=45952#productTabs1

Plus the 2-speed motor/countershaft pulley conversion..

Gets me a 1/2HP variable rpm motor with the higher top spindle speed I'm looking for...

Now if I could just find that darn 2 speed countershaft pulley by itself....

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strokersix · Jan 31, 2019

The vfd can wind your motor up faster than 60hz. I've read that nominal 1800 rpm motors can often be run up to 3600 without problems.

iwananew10K · Jan 31, 2019

You really don't need it....just the VFD conversion will do what you want.

size motor pulley so that when you are running whatever motor you use at max HZ for that motor you have your desired top speed...oversize the motor HP so when you dial it down for your low speed you have your desired HP.
You now have 6 speed "ranges" that you can adjust via the VFD...select belt step to get close and tune to the chips.
Done.

kitno455 · Jan 31, 2019

I also would skip all the funny business and use a bigger motor with a VFD.

allan

abarnsley · Jan 31, 2019

The High speed spindle was OPTIONAL... on SB Lathes.........

REQUIRED a Hardened spindle. And even that... did not get you very high spindle speed..

Cranking speed up on a standard Headstock, and spindle assy... WILL MOST LIKELY SIEZE the spindle bearings.

After siezing, due to galling of spindle, your spindle runout will never be the same....

If you want a faster lathe spindle speed, buy one with a roller bearing headstock.

You can't turn a pre 1920's plain bearing lathe design, into a modern racecar.

VFD will do anything the 16 speed setup will do, and provide smooth variable speed changes on the fly...

lonestar308 · Jan 31, 2019

abarnsley said:
The High speed spindle was OPTIONAL... on SB Lathes.........

REQUIRED a Hardened spindle. And even that... did not get you very high spindle speed..

Cranking speed up on a standard Headstock, and spindle assy... WILL MOST LIKELY SIEZE the spindle bearings.

After siezing, due to galling of spindle, your spindle runout will never be the same....

If you want a faster lathe spindle speed, buy one with a roller bearing headstock.

You can't turn a pre 1920's plain bearing lathe design, into a modern racecar.

VFD will do anything the 16 speed setup will do, and provide smooth variable speed changes on the fly...

This is the info I think I was really after...

Sometimes just because you 'can' do something, doesn't mean you 'should'...

I definitely don't want to screw up a perfectly good lathe. I prefer fleshing out ideas with those who've been there and done that before I dive in and make a mistake. Thanks to all for the advice.

My biggest reason for wanting a higher spindle speed is for turning aluminum, but that can be done at slower RPM, just not ideal....

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iwananew10K · Jan 31, 2019

If your machine is a side oiler headstock then it is fine to drive it to ~1400rpm....it's the same headstock.

lonestar308 · Jan 31, 2019

This is my headstock....

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iwananew10K · Jan 31, 2019

As long as condition is good, no problem...you may drive it to the top speed provided by the 2 step motor/countershaft.

0.75 HP, 1800 RPM, Brook Motor with 1 HP, 115 Volts, Teco VFD at Dealers Industrial

Pull up the specs for that motor...it's an inverter duty, and possibly one of the best deals going on a brand new factory warranted motor.

tobnpr · Feb 1, 2019

I have a 16-speed V-belt, repowered with 1hp inverter-duty motor with Teco L510.
If you plan to overspeed the motor continuously, inverter duty is required so the windings don't burn up- or so I was told...

Worth mentioning, that even though I have the capability, I rarely mess with the motor frequency- and still belt shift like I always did before.

comstockfriend · Feb 6, 2019

Note that in HTRAL, the 16 speed unit is really only 14 speed, two of the backgear speeds are too fast and NOT recommended by SB. On my v-belt lathe I used a segmented belt, very tight clearances on the two largest steps so hard belt changes.

With a VFD, you'll have to map out the acceptable frequencies for each belt setting so that you are not overspeeding the plain bearings or running too fast in backgear. For some tasks, you will have to change the belt setting for higher torque, etc.

John

9A 6speed to 16 speed conversion?

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