Question for Machinists!?

[LoserShoes]

Probably a two speed motor, like wash cycle and spin cycle.

If it 's a Sears, take it to one of their service centers and they should be willing to show you the correct hookup.

Steve

[TopCatGr58]

Hey folks,

An update on this motor I've been trying to get to work. I took some Ohm readings across the wires, here's what I found:
Blk to White: 3.8 ohms
Blk to Orange: 3.8 ohms
Blk to Blue or Yellow: Open circuit

Blue to Yellow 1.8 ohms

White to Orange: dead short:0 ohms

White to Blue or Yellow: Open
Orange to Blue or Yellow: Open

Randy was able to find some basic wiring diagrams(THANKS!),but not this motor specific. It's a GE motor....1/3hp not 1/2 as expected.

I had a switched plug outlet that I was able to try to connect combinations of wires to testing to see if I could get it to turn.

I connected Black to blk, White to White....nothing!

Then, thinking it was a capacitor start motor, tried also adding the Yellow to Blk and Blue to White.....It turned!!! I had only left the switch on for a second at first. Then I decided to try it for a longer time, and after 10 seconds....I let the SMOKE out of the wires

It came from deep within the motor case. I felt all 5 wires that were coming out of the motor, and none of them felt extraordinarily warm!? This motor was a cheap washing machine one I got off ebay for $20.00, it would have been a bigger pain to try to mount it to my lathe anyways, and probably too weak also.

I'll be going to my local Harbor Freight store to try to pickup a 3/4 hp General Purpose motor to mount to the lathe!

Could still possibly find a use for this other motor, IF I can figure out the wiring, and IF I haven't already fried it too much internally, I had turned off the power as soon as I started seeing the SMOKE! Anybody got any other ideas, suggestions for wire combinations?
T.C.

[pathfinder]

Normally when the magic smoke comes out, it no worky nomore. No way I know of to replace said magic smoke either. Don't ask me how I know this ancient and true fact of anything with wires, windings, capacitors, diodes, hard drives, circut boards ect.

[LoserShoes]

A lot of 9x20 users replace their motors with treadmill motors to get a DC Variable speed setup. Motor and controller can be had for about $100 or less surplus. Can give you a URL if interested.

Steve

[TopCatGr58]

Well,

I went to Harbor Freight, found a 3/4 HP General Purpose motor, bought it, got it home, followed the wiring directions to reverse the standard CCW rotation, and mounted it with a 5/8" shaft pulley, and threw the switch, and it just hummed and didn't spin the LATHE!!

I then reduced the drive ratio on the lathe, and it did spin it, but you could hear the capacitor starting mechanism kicking in and out continuously, trying to give it enough torque to spin, but it wasn't able to spin up to it's normal 1725 RPM's.

The other little 1/6hp motor was at least able to spin it albeit very slowly! So... it looks like I'll be going back to H.F. and seeing if they will exchange the 3/4 one for a 3HP one? Problem is that the 3HP only spins CCW and is not reversible, so...I'll be making a mounting frame to mount it off the end of the lathe, so that the CCW spin will turn the lathe the right direction, and HOPEFULLY, it'll be strong enough with enough torque to spin it at the higher speed I want. The larger motor spins at 3krpm, so I may need to get a smaller pulley, but I've already got a fairly small pulley on there. The 3HP is rated at compressor duty, I know it takes a bit more torque to turn a compressor pulley assembly!

[JWSanders]

That dosent seem right. Most of the gate motors I work on are 3/4 hp and can pull a 500lb gate no problem. I usually ride on the gate to test the strength as well, and I ain't all that light. Plenty of torque. That is a smaller pulley on the motor turning a larger one, which has the chain sprocket of the gate chain on the same shaft as the larger pulley. Will generally move the gate pretty quickly.

Are you sure the lathe shaft isn't bound up or something? It should spin it easily. Is the capacitor start wired correctly, as well? I really think that motor should work in at least some capacity.

[wfold]

I know you said you were going to use hss at first and then move the carbide later if you felt more confident but with a belt drive I don't think that would work very well. belt drive usually equals low torque and taking a deep cut even on aluminum would like be enough to stall you out. I have stalled (slipped) belt drive with heavy sandpaper on 3" od brass.

Always remember you can still be precise even with slop the cross slide as long as you rely on where the slack is taken up instead of the increments on the gauge. When it gets close spend the time to take smaller cuts and measure with your vernier or whatever you are using more frequently.

and of course... The speed of the feed is proportional to the heat of the meat... as long as the ass is constant!

[TopCatGr58]

Hey JW,

Well, I did disassemble the headstock, and clean and regrease the reduction wheels internally where they spin on the main workpiece shaft. But I also went back and got a 2HP motor, was reversible, designed for compressor duty, and it turns it nicely. The motor pulley is 2" diameter, the main headstock pulley is 14" diameter, a ratio of 7:1 reduction. So...even though the motor is 3400 rpm, the workpiece isn't spinning too fast, although I was wanting to try to get it up to 500rpm, to get close to the recommended SFPM rate of 900 for the aluminum stock, at 5.25" diameter, it's about 1.2F/RPM .

My old leather? belt had gotten rather stretched, and wasn't able to grip the wheels adequately, and was getting a fair amount of slipping. I took it apart and off. I went to the AUTO store and found a ribbed drive belt, only 1/2 as wide, but reinforced rubber, and it seems to work well!

The headstock has a large pair of reduction gears that drop the rate another 8:1. Using this, the 2hp motor I got can handle the middle large wheel reduction ratio of 1.33:1, so from 485RPM of the large pulley, with the 8:1 reduction, and 1.33:1 secondary reduction, I'm getting about 45rpm at the workpiece.

Wfold, I DON'T HAVE any increments on the crosslide wheels! SO....I'll definitely be doing it thru the measurements of my 1.00" slide/dial machinists gauge!! Thanks everyone for your input, this is definitely a learning experience.
T.C.

[TopCatGr58]

More machining woes!

Well,

I finally got that metal cutting bandsaw that I "thought" I needed to more effectively cut 1.1" slices from the 5.25" diameter T-6061 aluminum log, since I had already tried my 7" circular saw with a metal cutoff disc, then a sawsall, then a portable band saw!

This one is rated at 200 fpm blade speed, with 14teeth per inch, it's the coarsest blade I can use. It's only a 1/2HP motor, and it gets rather warm/hot after about a 1/2 hour of cutting. I even have a fan blowing on it. I have to rotate the log 1/4 turn as I progress thru the cuts. I'm sure IF I had put out twice the $$ for an industrical type, it would probably cut faster, but for the $170.00, I guess I can't complain.....too much!

The other problem is coming to the realization that my old lathe is just OLD. I tried cutting out the recessed section in one of my aluminum slices that would be needed for making a S.O.F.A., and after 5-6 passes from center to edge over about an hour, at only 20 thousandths or so a pass, I maybe got between 1/16 to 1/8" deep recess cut into it. The recess needs to be 2/3"!!

Doing this as a one off piece for myself is one thing, but wanting to mass produce these just isn't feasible time wise THIS WAY!! Looks like I need to get a MILLING machine to be able to cut out the amount of material I need to remove! Harbor Freight has this decent looking multi-machine combo mill and lathe, on clearance sale for the ones they have already in stock. Regular price is around $650.00, sale $475.00! Trying to get SWMBO to let me get it. But this brings me to my next question!!

With this type of machine, how hard would it be to rig it up with some sort of CNC type control for the table that holds the workpiece while the mill runs? What kind of price would I be looking at for this MOD/Addition? Or am I just dreaming?

The problem with this part is that it's ROUND, so doing the milling by hand would be rather fun=difficult also!? Any thoughts?
T.C.

[JWSanders]

I know exactly the mill you're talking about. I have been trying to come up with a reason to buy it for a long time now. I have several, but none has been able to make me come off the cash for it. If I had a suitable place to put one I'd have probably already gotten it by now.

There are a lot of systems out there for converting a mill to CNC, but they can get pricey. The key is getting high quality stepper motors (to take over the functions of the wheels), and a good controller. Most of the 3-Axis kits I've found are quite expensive at around $1000 to as much a 3 and 4k for super high precision.

http://www.acumotion.com/cnckits.htm

There are a lot of others, too. I know it can be done cheaper, but it will be a bit of a task. Luckily, there are less expensive options for CAM software (share and freeware) out there. Would still need a CAD package to design with though.

I've considered it a project for later on. I have too many already! Hell, If I get half the things I want to do done in my lifetime I'd consider myself lucky.

[gerkenbruce]

HI TC
How abought taking a CNC class were you can get your hands on some of thoes wounder machines and your going to need a bigger place to work.

XSively
Bruce

[mro]

Cheep Tools

IMHO
Low end machine tools are fine for hobbies, making "a" part, but you will never be satisfied trying to make a production run. That’s not what there made for.

A serviceable used machine (cost 4/5 times what a harbor freight machine sells for?) will produce 50 times as much 20 times faster and do it right.
Make your oil goody, caliper pistons, etc...etc..etc..........


mro

[LoserShoes]

What kind of spindle speed are you using? Aluminum needs a fairly high rpm to to turn well. Also when you a cutting with the saw, are you using a coolant (lubricant). WD40 or silicone spray works real good. Just give it an occasional shot to keep the aluminium from galling on the blade teeth.

You really need to get a Machineries Handbook if you don't have one. Should be able to find one used cheap, as they don't change much from year to year.

I think there is a Yahoo Group devoted to getting that saw working ok.

Steve

[rover]

TC, can you rig up a machine (die grinder, or other rotary tool) to mount on the tool post of the lathe, and still get to the center of your workpiece? If so, put an end mill, 1/2 inch or larger in the tool, and remove the metal from the center of the S.O.F.A. that way. Should go MUCH faster, and rotating the lathe very slowly, should be very accurate.

[TopCatGr58]

R.T.F.M.

Thanks for the input!

Mike(MRO), I'm just hoping to be able to turn out 5 or so pieces, not several hundred, so a little more time and less $$ spent is okay, it's just that the Lathe I have is "turning" out to be a piece of crap. As Steve eluded to, I'm not able to spin the workpiece as fast I need to be able to make the proper speed and smoothness of the cuts, and the old sleeve bearings don't secure the spindle as tightly as it should, so it's just another reason why it's not working well.

Steve, several times during the bandsaw cutting process, I stopped the saw, and checked the blade, and it wasn't hot at all, neither was the log! Also, if I lubed the saw, it wouldn't drive as well on the drive spools, possibly slip? The aluminum was being cut in nice little shavings, coming out of the piece almost like a fine dusting of chips/shavings! It was the MOTOR that was getting quite warm after running for 30 minutes or more at a stretch, again, probably wasn't designed for "continuous duty" type activity, more like cutting threw a piece of pipe or sheet metal for just a few minutes!

Rover, I like your idea. I have a variable speed hand drill that I could probably find a way to rig up to the tool holder, and with an end mill bit mounted, I could turn the work piece by hand to rotate the piece into the mill bit in a circular pattern, and then just adjust the cross slide to move inwards or outwards thru the piece. I'll have to look into getting an end mill bit! I know the drill isn't designed for such lateral forces that are incurred during milling, vs. straight drilling pressures. But it's not that expensive a drill, and it might get me thru a few pieces until I can afford that fancy multi-machine!

JW, you're starting to sound like US, you gotta have a MANUAL!!! I downloaded a machinist/LATHE FAQ guide a while back, and read it, was very informative. Lots to learn, I know!
T.C.