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QSIMDO
09-09-2005, 04:38 PM
As I'm feeling my way along with the new lathe and theoretically picking up valuable lathe operating information I find that I'm changing lathe speeds...a LOT...in my quest to learn how different materials react.

However, what is being learned foremost is how arthritis reacts to constant belt changing manipulations! http://bbs.homeshopmachinist.net//frown.gif

My questions; is there a way to control speed on the OE 110 AC motor or would a DC motor & control be the way to go?

Knowing less about electricity than machining, what would be a desirable setup for DC horsepower, controller, etc.?
I've read about treadmill motors but wonder if one would be able to replace the 1HP 1720rpm motor on my lathe.

SGW
09-09-2005, 05:59 PM
Variable-freuqency drives work only on 3-phase motors. I assume your 1hp motor is single-phase, so you can't use a VFD with it.

That being said...it may be worth the expense to replace it with a 1hp 3-phase motor and a VFD. I've got a VFD on my milling machine, and it's great. Dealers Electric www.dealerselectric.com (http://www.dealerselectric.com) has some deals on motor+VFD packages. (Usual disclaimers)

topct
09-09-2005, 07:10 PM
What brand of lathe?

------------------
Gene

QSIMDO
09-09-2005, 09:42 PM
Grizzly, 11X26 model 9972Z.

Hmmm.... VFD and 3 phase eh?
Those prices aren't all that horrid either.

[This message has been edited by QSIMDO (edited 09-09-2005).]

Bill Pace
09-09-2005, 10:20 PM
I did my 12x36 Birmingham with DC. A careful watch on ebay for 2-3 wks and I got a 1hp motor and a controller for about $125. The Birm comes with a 2hp rated (Chinese rating???) and, yes, I was a bit skeptical of the 1hp having the oomph, but, if anything, I've got more power now. And -----is it ever SWEEEET!!

QSIMDO
09-10-2005, 12:57 PM
I checked eBay this morning and my head is spinning((((( http://bbs.homeshopmachinist.net//frown.gif )))))!

How do you select the correct DC motor? HP, RPM , permanent magnet.....??

Bill Pace
09-10-2005, 05:03 PM
<font face="Verdana, Arial" size="2">Originally posted by QSIMDO:
I checked eBay this morning and my head is spinning((((( http://bbs.homeshopmachinist.net//frown.gif )))))!

It can be a bit overwhelming....I think the more you become familiar with it the less this seems so........


How do you select the correct DC motor? HP, RPM , permanent magnet.....??</font>


There will be a learning curve to the DC terminology as with most anything (same will be true with 3ph variable speed), but it aint rocket science. I had to teach myself (just enough to get by)---I might throw in here that I,m retired and am able to possibly spend more time persuing these ventures than otherwise. I've now got 6 tools in my shop converted to DC and my current project is constructing a 2x48 or 2x72 belt sander with DC drive.

Here is a couple of examples of what I would have been looking at on ebay for your lathe. (probably opening myself up to a lot of "that aint the way to do it---that wont work, etc etc) but what I did works, and works very well.....

http://cgi.ebay.com/Baldor-3-4hp-90vdc-perm-magnet-DC-motor-56C_W0QQitemZ7543738756QQcategoryZ42920QQrdZ1QQcmd ZViewItem

http://cgi.ebay.com/Danfoss-1hp-180vdc-perm-magnet-DC-motor-56C_W0QQitemZ7543738933QQcategoryZ42920QQrdZ1QQcmd ZViewItem

and a controller that would work........

http://cgi.ebay.com/KB-Electronics-DC-Motor-Variable-Speed-Control_W0QQitemZ7543992981QQcategoryZ71393QQrdZ1Q QcmdZViewItem

QSIMDO
09-10-2005, 09:11 PM
Ok, progress! Thanks Bill.

I would have been attracted to the 1hp motor but how would it be set up with the 1800 max rpm?
Just set the belt drive pulleys for max designed rpm of the lathe and then use the control for slower speeds?

Forrest Addy
09-10-2005, 10:34 PM
Wrong. You may find you need the mechanical advantage of the geating belt speeds. Use the spindle speeds as you need them.

The variable speed feature is nice. I have VFD's on all my machine tools. As the motor RPM drops your developed HP decreases in proportion because the motor torque is constant. Thus you can take a heavy cut on a smaller dia but a full swing part running at low motor RPM will allow only a light cut.

Physics will kill you.

JRouche
09-10-2005, 11:02 PM
<font face="Verdana, Arial" size="2">Originally posted by Forrest Addy:

The variable speed feature is nice. I have VFD's on all my machine tools. .</font>

VFD's ? I thought he was talking about DC drives?

"As the motor RPM drops your developed HP decreases in proportion because the motor torque is constant. Thus you can take a heavy cut on a smaller dia but a full swing part running at low motor RPM will allow only a light cut."


Are you saying that the torque will be constant through out the RPM range but you will still lose "cutting ability".

I thought it was the torque that accomplished the turning force? JRouche

Bill Pace
09-10-2005, 11:16 PM
<font face="Verdana, Arial" size="2">Originally posted by QSIMDO:
[Just set the belt drive pulleys for max designed rpm of the lathe and then use the control for slower speeds?

[/B]</font>

No, variable speed is not quite THAT versatile...you would probably find that a mid range belt setting would cover 90% of your needs, but you would still find certain operations that required a belt change (threading for instance (slow) or, emerying/polishing on a final finish (fast)

Feel free to contact me off site for any way I might could help.

Bill Pace

Forrest Addy
09-11-2005, 12:42 AM
Mr Rouche

True, torque is force at a particular radius but on a machine tool cutting force is a matter of leverage or more accurately moment as a function of motor HP Vs RPM.

A 1 HP motor at 1800 develops about 3 lb ft ot torque. This gives you a cutting force of 412 Lb at 80 ft per minute; a nice range for HSS. If your machine is geared to turn 350 RPM at full motor RPM you got 80 ft per minute cutting on a 1" dia. If you slow the motor down to cut a 6" diameter you need 58 RPM to get 80 ft/min and 1/6 of 412 lb gives you 69 lb cutting force.

When you give up the geared/belted spindle speed changes to vary spindle RPM and us the motor alone to vary the spindle speed you also give up leverage/mechanicsal advantage. Most cutting situations don't requires full HP cuts but when you need the stock removal and your machine fails to perform you need to understand the reasons why.

Use the variable speed feature for its versatility but keep the gears and spindle speeds for mechanical advantage when you need it.

[This message has been edited by Forrest Addy (edited 09-11-2005).]

ibewgypsie
09-11-2005, 10:48 AM
I am still waiting on someone to use a hydraulic hydrostatic transmission off a lawnmower on a lathe.

Looks to be the best of both worlds.

Bill Pace
09-11-2005, 10:57 AM
[QUOTE]Originally posted by ibewgypsie:
[B]I am still waiting on someone to use a hydraulic hydrostatic transmission off a lawnmower on a lathe.

Hmmmmmm........You know, that sounds VERY interesting!!

I remember when I got my lawn tractor with it, I was blown away by the difference compared to a tranny.......sorta like variable speed on a lathe....

Forrest Addy
09-11-2005, 10:59 AM
Hydraulics are great. With them you can cram a lot of torque and power in a small space. They're very controllable and verdatile.

Packaged hydrostatic transmissions like in a lawn mower or a small tractor drive might be awkwardly arranged for use on a machine tool but they will do the job.

If you elect to make use of a lawnemower hydrostatice transmission, be sure you get one that has about 6 to 1 constant HP speed range. Some of these hydrostactic drives are capable of up to 16 HP so it might take a full HP just to drive the replentiching pump and other internal loads. Choose carefully.

Remember hydraulics eventually, always, leak.

[This message has been edited by Forrest Addy (edited 09-11-2005).]

ibewgypsie
09-11-2005, 02:34 PM
Forrest.. So Do I.. hopefully controlled thou.

(leak).. http://bbs.homeshopmachinist.net//biggrin.gif

QSIMDO
09-11-2005, 04:53 PM
Uh oh, now the ideas are coming out!

I've got a Cub Cadet 122 which is gear drive but my buddy has a 147 that I've been lusting after and that Sundstrand unit is bullet proof!

But talk about stripping gears? That thing is a touque monster.

And, while I haven't convinced myself the price is worth it I stumbled onto this today.
http://www.robotmarketplace.com/

Thses boys HAVE some DC motors!

Steve Stube
09-12-2005, 03:29 AM
I have used the Vickers hydraulic units on shop machines - band saws, lathes. They are a very nice unit, variable speed and instantly reversible. There is actually two wobble plate pumps in it (6 or 9 piston, I forget). A little noisy, quite expensive, and a horsepower thief. Not sure you will be able to read it in the photo but this one is 1 HP input and 3/4 HP output. This is the size I used on Delta 14" band saws for metal cutting and it is a workhorse setup.
http://img.photobucket.com/albums/v19/ceethese/Posted%20photos/vickersvariablespeedSmall.jpg

When I posted the above I was thinking about it as if it was just the other day (recently) but upon reflection, and a search for this Vickers unit - which I couldn't find anywhere - I remembered that the last install of one of these was ~early 80's. I personally had started switching my own shop tools to DC shunt motors for variable speed in the early 70's and soon after started building controllers for them but still had some interest in these Vickers drives based on word of mouth and a small Vickers driven Craftsman lathe I had in my garage/shop at the time. This was hardly more than a hobby activity but I squeaked a few bucks here and there setting up machines for others and rebuilding machines I purchased for repair and resale. Many of the repaired machines were outfitted with a variable speed drive if it offered an advantage and the proceeds went back into my hobby shop activity.

[This message has been edited by Steve Stube (edited 09-12-2005).]

ACF
09-12-2005, 07:03 AM
<font face="Verdana, Arial" size="2">Originally posted by QSIMDO:
Uh oh, now the ideas are coming out!

I've got a Cub Cadet 122 which is gear drive but my buddy has a 147 that I've been lusting after and that Sundstrand unit is bullet proof!

But talk about stripping gears? That thing is a touque monster.

And, while I haven't convinced myself the price is worth it I stumbled onto this today.
http://www.robotmarketplace.com/

Thses boys HAVE some DC motors!</font>

I just had to put $200 in parts and about 12 hours of time to fix the sundstrand in my cub cadet. I wouldn't rate the unit as bulletproof. No, I didn't abuse it, just cut grass with it.

Chris

topct
09-12-2005, 08:59 AM
Here's what I have decided. I have a DC motor and controller out of a treadmill that I had thoughts about putting on my Southbend 9c. It sure would be neat to have that variable speed?

But then I began to really think about it. I also have a Taig lathe. It has sixteen speeds the way I have it set up. But how many of those speeds do I really use for everything? Two. And I don't know what they are as far as rpms go. I just use those two speeds. Plastic, brass, bronze, aluminum, steel, stainless, it doesn't matter I still only use those two speeds. I can't thread on it, so slow is not neccasary.

This is what I have discouvered. Although the speed may be important what's just as important is the form of tool and how it is caused to contact the surface of what ever I'm trying to machine. It doesn't matter what speed the thing is going if I don't have the tool set up right or ground right, I make crap.

Here's my suggestion. Instead of jacking around with all the speeds and the belt changes, why not select a speed somewhere in the low to middle of it's range and keep trying differant tools, angles, whatever, instead of changing the speed. I really think that you will find that most of the time you will not need to change speeds so often and that when you do it will be to one just one up or one down from where you are starting from.

I have looked at the lathe you have and I can't remember what speeds it was capable of, but I do know there is really only one or two at most that would work on just about anything I would want to machine.

There, I just saved you a bunch of time and money. And have done the same for myself. Besides the old Westinghouse that came with my 9C is so quiet I can't even hear it run. The DC motor makes this singing sound that would be eratating.

As for what to put this really nice DC motor on, come here MR. drill press and bend over.



------------------
Gene

[This message has been edited by topct (edited 09-12-2005).]

QSIMDO
09-12-2005, 05:29 PM
Well...that was easy.

Gene, I owe you a beer!
I guess I just got caught up in the tech of it all.

ACF; yep, I don't know how old yours is but I had to rebuild the engine on my 40 year old Cub...can you imagine?
Piece o' junk. http://bbs.homeshopmachinist.net//wink.gif

Nothing lasts for ever, eh?

Forrest Addy
09-12-2005, 11:06 PM
What you soon discover in the commercial world is the boss wants production so a guy new to the shop soon learns to use the machine tools and feeds and speeds and tool grinds and carbide tooling to its full capacity or get a lecture - or an opportunity to look for another job.

At home it's a different deal. You can diddle around without let or hinderance. You can take as long as you want and explore technique possibly inefficient but interesting.

I'm not surprised to find many who used only a limited part of their machine tool's working range. Usually their work falls into a limited range of materials or is consistant in size. I know of an OKK milling machine that was worn out machining tens of thousands of particular valve body. When we opened the spindle transmission we found only one train of gears had wear on them and the shifters were pristine.

Years ago when new apprentices fell in my chutches, I taught them to use the machine's full capacity at every opportunity. The object of any machining operation is to reduce the stock to finish cuts in the most efficient means possible. If the machine has a 15 HP spindle motor then 15 HP worth of chips pouring off make a musical jingle to the boss's ears.

If you're going to be a good home shop machinist I would suggest you do so with the idea in the back of your mind that should you wish to find employment as a machinist your home experience would serve you well. So for that reason I urge you all to work your machinery to their capactities if the job warrants it.

Here's another way of looking at it: the more efficiently you use you machine tools the less wear you put on them per part manufactured.

QSIMDO
09-13-2005, 08:40 PM
Sir, believe me when I say I wish nothing more than to do honor to the demanding and precision vocation many of you dedicated your lives to. My father was a skilled Tool & Die maker and in some small way I also wish to honor his memory by showing at least a passing interest in the processes that underwrote my well being all those years.

But, alas, I have no where near the skill, talent and ability (plus the lack of comfortable physical capability I alluded to earlier)...or time...to delve into the more obscure nuances of machine tool operation, no matter what level of desire I posess.

Hence my interest in simplifying the machine operation either mechanically or as "topct" Gene suggested.

For the time being I'll just operate within more narrow parameters, enjoy what I can and try my best to absorb what I read here.

But I'll also tell you this.
I'd give anything to have another lifetime to understand a fraction of what many of you have forgotten.

J. Randall
09-13-2005, 09:44 PM
QSIMDO, I am doing a little detective work here. From your username and reference to arthritis, I am wondering if you have the same condition that I have. I have a severe case of AS, if I am getting to personal please just tell me to bug off. James

CCWKen
09-14-2005, 12:16 AM
Here's a link to a Brigeport Mill conversion to DC drive. A lathe would be similar in that you'd be replacing the motor.

http://truetex.com/dcdrv.htm

QSIMDO
09-14-2005, 04:45 PM
<font face="Verdana, Arial" size="2">Originally posted by J. Randall:
QSIMDO, I am doing a little detective work here. From your username and reference to arthritis, I am wondering if you have the same condition that I have. I have a severe case of AS, if I am getting to personal please just tell me to bug off. James </font>

I wouldn't dream of responding in such a manner!
No, mine is just a rapidly advancing case of OA throughout but with thumb and wrist joints riding bone on bone and the only course of correction is fusion.
Can't hold a magazine for more than a few minutes, but I digress.
My condolences for your situation.

My user name is an acronym I used on a license plate for my last bike; Quite Simply It Means Ducati Owner.

No longer of any use since I sold it and now ride a BMW. Go figure.

QSIMDO
09-14-2005, 04:47 PM
<font face="Verdana, Arial" size="2">Originally posted by CCWKen:
Here's a link to a Brigeport Mill conversion to DC drive. A lathe would be similar in that you'd be replacing the motor.

http://truetex.com/dcdrv.htm</font>

Thank you!
That looks interesting and I'll read up on it.