Motor Trouble and a Bearing Question

[Teenage_Machinist]

3 prolblems... First is there an easy way to measure the speed of a motor? I have 2 motors and neither have nameplates!

Second, How am I supposed to wire a reversable AC motor. I took apart an old garage door opener, and I get a power cord with white/ black 1prong2prong and green ground wires, and a capacitor with 2 pins, and a motor with white, purple and orange wires. The white wire was direct to the cord and the other 2 wires went into the circuit board with the capacitor straddling them. I do not beleive there was anything else. How in all the many hells am I supposed to wire this thing up, reversably or not, to a wall outlet?


Third, I understand that the Darex end mill sharpener dispenses with the "surface grinder" mentality and has a cup wheel, a one-direction slide, and an air bearing spindle. Do you think I could build an HSM sharpener using bronze, ball, graphaloy, freelon, rulon, teflon, somethingeslalon, or other type of linear bearing/ make own air bearing and still have it work?

[tiptop]

ikrase, check on eBay for something like this.
# 320306719885 or # 250301187194

Sorry I can't help with your motor wiring.

Yes I think a home shop machinist could build an adequate end mill sharpener. Do lots of homework on your subject and go for it. If it doesn't work the first time figure out why and try again. Jay

[J Tiers]

With motors, AC induction motors, if you can determine how many poles there are, you can instantly determine nominal speed. 2 poles = nominal 3600 rpm, usually actually 3450 rpm at 60 Hz, 4 poles = nominal 1800 rpm, often actually 1725 rpm.

Since the "poles" can be hard to determine, something like the Starrett turns counter will work..... that and a watch. it simply gives you an indication of how many turns there are in a given time by the watch, which you convert to RPM.

Failing that, an optical tachometer such as is used by model airplane folks also works.

The reversible motor is non-typical, since most reversible induction motors have 4 wires, two main winding wires, and two start winding wires. You swap the start winding wires to start in the reverse direction.

Door opener motors may be different. Many are actually "universal" AC/DC motors, which reverse in a different way.

The capacitor you mention...... does it have any writing on it? It may NOT be a start capacitor at all, if it is a small value. A universal motor might have a capacitor as an interference filter.

[Norman Atkinson]

Bearing in mind

According to my records, under 100 posts and about 20 questions at a rate of about one a day.

Tell me, Ikrase, are you actually making use of the information which has been so freely given by many here?

[macona]

The Darex end mill grinders may look simple but the motors are balanced and have much better bearings than the standard general purpose ac motor.

And from what I hear they are only so-so.

Air bearing spindles are not easy to build. There have been attempts to build one from spin-jigs but they have never worked out well. There are very high tolerances needed and very good surface finishes required. You need a cylindrical grinder. Or maybe a Sunnen hone. (Not a brake or cylinder hone. This is a machine)

If you need endmills sharpened call some local tool sharpeners. Its usually cheaper than buying a new one. And make sure you start by buying quality stuff. Chinese endmills are barely good for milling plastic.

Machining is not cheap hobby. I have spent tens of thousands and hundreds of hours scrounging in the past couple years to get the shop I have as well as many of the others here.

Like J Tiers said, a lot of openers have universal motors. Know a universal motor as it has brushes. But some of the newer one are not. It might be a capacitor run motor. If that is so then with the capacitor between the orange and purple apply the hot wire to orange and it will run one way and apply it to purple and it will run the other way.

Not sure. Dont blame me if you toast the motor though.

When a motor is running you can usually tell if it is 1725 or 3450. 3450 RPM motors really spin up there...

[winchman]

There's a wiring diagram for Genie openers here:

http://lib.store.yahoo.net/lib/aaaremotes/Genie404414wiringdiagram.jpg

My guess is that the white wire is common, and applying power to either of the others will make it run one way or the other. You can try that out using a 100 watt light bulb in the circuit to protect things if the wiring isn't correct.

These motors usually have no cooling, so take that into account in whatever plans you have for the motor.

Roger

[oldtiffie]

Good advice

The Darex end mill grinders may look simple but the motors are balanced and have much better bearings than the standard general purpose ac motor.

Good advice macona.

That's very much so. The whole rotating assembly (without the grinding wheel and balancing hub) must be very accurately dynamically balanced at the speed at which it is to to run. This is a stretch, but the process is not too dissimilar to that on your car tyres where they add weights to get the right degree of balance except that with spindles the balance is achieved by strategic very accurate drillings for weight removal. Further, the grinding wheels should be mounted on a very accurately (statically) balanced hub so as to not compromise the balanced spindle.

And from what I hear they are only so-so.

Can't comment on that although I have no reason not to believe it.

Air bearing spindles are not easy to build. There have been attempts to build one from spin-jigs but they have never worked out well. There are very high tolerances needed and very good surface finishes required. You need a cylindrical grinder. Or maybe a Sunnen hone. (Not a brake or cylinder hone. This is a machine)

Very very true.

I have an air spindle on my surface grinder and I can tell you that the spindle is superb - precision finish and accuracy with a hard chrome on the diameter and the bore it engages with is precision lapped to the extent that getting the spindle back into the bore is a work of art and requires a lot of skill and patience. The bore for the collets etc. in the spindle must be very accurately sized and aligned to the spindle axis. When I switch the air on the spindle will slide under its own weight at a slope of less than 1/8" per foot (1:96).

If you need endmills sharpened call some local tool sharpeners. Its usually cheaper than buying a new one. And make sure you start by buying quality stuff. Chinese endmills are barely good for milling plastic.

There is no time cost for me, but I don't even bother to sharpen the diameters of end mills less than 5/16" (8mm) as I just toss and replace them. I will sharpen the ends after I have enough to make it worth while setting up and cleaning up the tool and cutter grinder. I try to have several of each common end mill I use. I NEVER use an end mill that is not sharp as it creates all sorts of problems.
I buy a lot of Chinese stuff, but milling cutters are not one of them. I only buy top quality local (OZ) made cutters as it pays off handsomely.

Machining is not cheap hobby. I have spent tens of thousands and hundreds of hours scrounging in the past couple years to get the shop I have as well as many of the others here.

That would just about have to be the understatement of the year!!. I don't seem to have anywhere near the stuff to "scrounge" through here in OZ as many seem to have in the US and to a lesser extent, in UK.

Like J Tiers said, a lot of openers have universal motors. Know a universal motor as it has brushes. But some of the newer one are not. It might be a capacitor run motor. If that is so then with the capacitor between the orange and purple apply the hot wire to orange and it will run one way and apply it to purple and it will run the other way.

Not sure. Dont blame me if you toast the motor though.

When a motor is running you can usually tell if it is 1725 or 3450. 3450 RPM motors really spin up there...

I will defer to the experts here as "electrics" are my weak subject.

It is quite feasible to make a functional end mill sharpener with/from a "Spindexer" to sharpen the ends and diameter, or even use a chain-saw grinder to sharpen the ends only.

A Tool & Cutter grinder is much more versatile that just an end-mill sharpener. It would be hard to imagine (m)any tools that it couldn't sharpen in many HSM shops.

But we aware that even if you have the best of T&C grinders with all the accessories and "bells and whistles" that T&C grinding requires a whole new skill-set that requires a lot of reading, thought and VERY safe work-shop practice. They can BITE and bite hard as they are not very forgiving at all.

But used carefully and considerately they are an excellent and very accurate and versatile tool.

[oldtiffie]

Questions

According to my records, under 100 posts and about 20 questions at a rate of about one a day.

Tell me, Ikrase, are you actually making use of the information which has been so freely given by many here?

Thanks Norm.

That needed to be said/asked. I was on the verge of doing it several times.

If the OP genuinely requires the info for either general or specific use, or just knowledge for knowledge's sake - he should say so.

I don't mind putting the effort in if it will really help someone but I'd be more than just a bit pi$$ed-off if I was being "used up", "taken for a ride/fool" etc.

If in the hopefully unlikely chance that it is all just a "wind up" to set people off on a "wild goose chase" with the best of intent to answer questions he already has the answers for - that is dead-set "trolling".

So, for the OP, I suggest that it would be better for all concerned if you were to couch your questions in terms of the problem that needs to be addressed.

[JoeFin]

I've said it before, and I'll say it again - You want to sharpen End Mills, you're going to need 1 of these



Not only can you sharpen end mills but every thing else under the sun that needs a fine edge AND with the added benefit of small I.D. & O.D. grinding

[JCHannum]

For some reason the Tiffster and Norm feel compelled to become moderators. Considering many of their own posts, this is quite ironic.

ikrase is a very obvious newcomer to the hobby, and is somewhat overwhelmed by much that is involved. Many of us were in that same boat at one time and to suggest that he not ask questions is doing him and other newcomers a great disservice. It is difficult to ask questions and, perhaps, reveal your lack of knowledge, and those who do ask are presenting an opportunity for others to learn as well.

If you do not wish to respond, don't, but don't discourage someone from using this site as it is intended to be used.

[oldtiffie]

Keeping an edge

A good quality "Spindexer" on a tilting angle plate will do it as well. The "Spindexer" spindle will go close to emulating an air quill spindle.

The main advantage of the air-quill and the "Spindexer" spindle are that the table lateral feed can be locked when sharpening end mill spiral edges. Most other method require the table to be moved laterally while the quill/spindle is rotated when sharpening the spiral outer teeth on and end mill.

I have a similar set-up to Joe Fin as well which works as well as Joe says.

Here is my T&C grinder with the air-quill mounted with collets fitted with a small end milling cutter set up in the collets and engaged on the "guide finger" for sharpening the spiral cutter edges. The air quill can be locked and rotated on the base - left-right and/or up-down - to sharpen the end teeth as well.

[J Tiers]

For some reason the Tiffster and Norm feel compelled to become moderators. Considering many of their own posts, this is quite ironic.

ikrase is a very obvious newcomer to the hobby, and is somewhat overwhelmed by much that is involved. Many of us were in that same boat at one time and to suggest that he not ask questions is doing him and other newcomers a great disservice. It is difficult to ask questions and, perhaps, reveal your lack of knowledge, and those who do ask are presenting an opportunity for others to learn as well.

If you do not wish to respond, don't, but don't discourage someone from using this site as it is intended to be used.

+1

EVERYONE who starts out has big ideas, lots of questions, and in some cases, very impractical plans.

Nothing WRONG with that.

Better someone asks questions than gets nowhere and gives up.

It actually never occurred to me to check in detail about the O.P., but now that I know, it does not create any problems for me. Hopefully ikase will report back on what he decided to do, or what more he determined about the motor. It is always good to know if advice is useful.

Even if he disappears off the forum, information from one person's question may benefit another.

I have certainly had a benefit from questions asked by others, in some cases they were questions I didn't know I needed to ask.

[oldtiffie]

How it is

For some reason the Tiffster and Norm feel compelled to become moderators. Considering many of their own posts, this is quite ironic.

ikrase is a very obvious newcomer to the hobby, and is somewhat overwhelmed by much that is involved. Many of us were in that same boat at one time and to suggest that he not ask questions is doing him and other newcomers a great disservice. It is difficult to ask questions and, perhaps, reveal your lack of knowledge, and those who do ask are presenting an opportunity for others to learn as well.

If you do not wish to respond, don't, but don't discourage someone from using this site as it is intended to be used.

Jim.

You points are well made and well taken.

I just wanted to be assured that putting the effort in was not wasted - no more and no less.

The format of the questions was not a great deal different from some others, including some who vanished when questioned and at least one other on physics and mechanics who it turned out after repeated questions was getting people here to "assist" with assignment work.

I at least, find it is much easier and quicker to respond if I have at least some indication of what the information required is to be used for.

I don't mind putting the effort in to assist at all, as we all, as you say, had to start somewhere and get assistance from others.

Getting some feed-back as to how we - or I anyway - are going with that assistance helps us/me to help the OP help himself.

If I have offended anybody in this issue I apologise as it was not intended.

[Rigger]

According to my records, under 100 posts and about 20 questions at a rate of about one a day.

Tell me, Ikrase, are you actually making use of the information which has been so freely given by many here?

Why don't you give him some of your PRACTICAL experience Norman.
After all you own what is it now 7 tool and cutter grinders but I can't recall seeing one post of them being used.

You are in a unique position having been thrown off the Quorn forum for grinding them down.

Pot, kettle, black ?

[Teenage_Machinist]

"Thrown off the Quorn Forum for grinding them down"
This begs a humor thread.
What about being banned from the chinese bandsaw forum for cutting their patience in half?

Machine Shop Practice and an old "big lathe, no mill" textbook have been very helpful to me. So have the Files of the Holy Order of the 7 Inch Chinese. However they do not have everything I need. In particular they tend not to tell about tool building, hobbyist stuff, ect. This forces me to fall back on "Ask a wiser person." This would be great if my great-grandfather was alive. He was another big-lathe-no-mill HSM, Pre-war, who made an IC engine which is currently being dismantled to fix what appears to be a shifted engine bushing that causes the piston and crankshaft to be out of line with the cylinder bore. One day it was running--- clatter, clatter, stop.

Unfortunately he died many years before I was born, and there is not other machinist in my family. My grandfather on 1 side=electronics, other side recently passed away, was a wood worker, but not a machinist. Must surely have been taught in machining by greatgrandad, but he never did that. My father is a craftsman who wears out many split point drill bits yearly (Stainless steel boat fabrications) and has had me make some parts once in a while, but not a machinist. The jobber who works near my dad and has done some jobs for him is an HSM by night and he introduced me to mini-tools, (and caused me to think that an 8 by 14 uses the same bench space as a 7x) but obviously is a bit of a prolblem to ask him about things. I have found that these fora are particularly helpful, and people like the Old Artificer, Mcgyver, ect, know what I need to know.

So yes, I am using advice. Speaking of vices, I am planning to make that screwless vise pretty soon, i.e. next month or so. Will take pix.
Some of this is of a general nature, like stuff about cutter grinding. Some is much more specific and practical such as the large number of threads about vise material (ARRRAGHH! WHY CANT THEY MAKE NON-WARPING STEEL!?).
Some times I just have a "great idea" and want to see whether anybody else has had it or thinks it workable. So no, I have no intention of disappearing and am NOT trolling. Motor help may have helped me a lot.