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View Full Version : I figured out what was wrong with my lathe - Now where do I get the part?



lost_cause
01-13-2013, 04:03 PM
Just before the holidays I brought home a used 12x40 Chinese made lathe. After dismantling, draining, cleaning and inspecting everything I was all set to try it out. I had run it back and forth a bunch of times, and everything seemed ready to go. The next day the electrical part gave out. With a little motivation from a friend and some spare time, I finally tore into it today. Luckily, the problem was easy to find. My knowledge of machinery electrics is pretty well non existent, so if it had been much deeper, I would have just stood around scratching myself and trying to figure out who could fix it. Here's a picture (large and low quality from my phone) of the problem:

http://i908.photobucket.com/albums/ac286/lost_cause_photos/0113131214a_zps2322438e.jpg

The upper right stud is broken off from the terminal block on the motor. between adjusting the motor for the new belt and running it back and forth a bunch of times it must have jiggled enough to contact and weld itself to the cover. No telling how long the stud has been floating around in there. Now, my question: What is the technical name for this part, and are they standardized and common? Being Sunday there aren't any local resources to go to, so I'm hoping someone here knows what it is and where I can get a replacement. I checked grizzly and Enco, and neither of them lists any parts internal to the motor, so I'm going to have to look elsewhere. There's a motor shop about 25 miles away from here I'm going to check tomorrow, but they don't always have good business hours. Are there any online resources I could look at if I can't get to the motor shop?

Tony Ennis
01-13-2013, 04:21 PM
If the piece is plastic, can you not make another from Delrin, etc? What sort of current and voltage are we talking about here?

duckman
01-13-2013, 04:23 PM
Epoxy it back in place and put some insulation over the stud.

KiddZimaHater
01-13-2013, 04:28 PM
Can you drill it, tap it, and use a new screw?

MaxHeadRoom
01-13-2013, 04:34 PM
Why not just do as many motors that do not have terminal blocks, use a suitable machine screw and nut and use heat shrink and electrical tape over the whole thing, both wires come from the same direction this makes it easier to cover suitably.
Max.

goose
01-13-2013, 04:58 PM
What you've got is a (broken) junction block or terminal block. McMaster, Graingers, etc will have one that fits your requirements. Cheap, $5 or so. The component you have is now of questionable quality so replace it in entirety.

alanganes
01-13-2013, 04:58 PM
I have a Taiwan Jet with very similar looking setup in the motor. That is simply a terminal block to make the electrical connections. As the other posters have advised, you should be able to pull the screw loose from it's weld to the cover, make sure to take care of an damaged wire insulation, re-make the connection. Properly insulate it with heat shrink and/or electrical tape and it should work just fine.

J Tiers
01-13-2013, 05:15 PM
All the connections are actually on the broken-off part, so there is no need to wait to get going. Tape it like the other guy said, and go while you source a block.

John Stevenson
01-13-2013, 05:24 PM
Use those horrible wire nuts you yanks are so keen on.

wierdscience
01-13-2013, 06:00 PM
Insulate it with rubber tape,close the box and pretend it never happened.

lost_cause
01-13-2013, 08:27 PM
wow, i'm amazed at the replies. i've seen so many people on other forums who are so scared of making any repair that isn't exactly like new that i expected it here too. i'd planned on taping it up to get by with for now, but i do want to make a more permanent repair fairly soon. there's literally one motor shop in a 50 mile radius of me, and i have to go by it tomorrow, so i'm going to see if they have anything like it. if not i've got a chunk of a plastic snow plow cutting edge that I can make a new one out of. i'd like to keep the ring terminal setup for now, since if i ever need to switch it to 120v then it will be simpler. a different type of forum i use has been so overrun with safety police that i would get much different answersfor a question like this - if i had 10 replies, 9 would only tell me how i would be liable if anyone got injured as a result of my shoddy repair. it's refreshing to see people who use their heads and common sense, and don't operate on only paranoia.

J Tiers
01-13-2013, 08:41 PM
My ONLY concern (which I forgot to mention) is that the wires appear to be burned/melted..... That suggests that there is (now, if not before) a possible bad connection, and you may want to check it.

Perfectly possible that the melting is from arcing to the case..... that is like welding, very hot. If so, you may just want to assure that there has been no loosening as a result. Loose connections heat, or arc, and continue to make trouble.

Weird has a good point... use the rubber tape that is thicker... it stands up to possible rubbing on case better.

lost_cause
01-13-2013, 08:52 PM
My ONLY concern (which I forgot to mention) is that the wires appear to be burned/melted..... That suggests that there is (now, if not before) a possible bad connection, and you may want to check it.

surprisingly, the wires look a lot better in real life than they do in the picture. my cell phone and picture taking skills don't do the world much justice. the insulation local to the ring terminals on the floating post did experience some excessive heat, but the damage is only in the insulation local to the post. i have already removed the terminal block to take with me tomorrow, and all the wires still seem fine. i'm going to clean all the connections before i put it back together, and i may add some heat shrink tubing over the one wire that looks the worst.

Don Young
01-13-2013, 09:00 PM
It looks to me like it might be worthwhile to clean up and tighten all the connections while you are about it. Those ring terminals might not be making real good connection with the wires or each other.

Scottike
01-13-2013, 09:00 PM
i've seen so many people on other forums who are so scared of making any repair that isn't exactly like new that i expected it here too.

call me "Old School", but more people are worried about covering their a&# than giving decent advice. (Shsss.. don't tell anyone I told you this.)
that's why I like it here!

portlandRon
01-13-2013, 09:02 PM
Looks like things got way overheated possibly by a lose connection. As part of your repairs it would be a good idea to replace the connectors on the end of the wire. Also clean up the other bolt studs and connection so that all surfaces are bright clean metal. If you don't do this and there is any poor connection/contacts they will over heat again and you will face the same problem.

lost_cause
01-13-2013, 09:15 PM
Looks like things got way overheated possibly by a lose connection. As part of your repairs it would be a good idea to replace the connectors on the end of the wire. Also clean up the other bolt studs and connection so that all surfaces are bright clean metal. If you don't do this and there is any poor connection/contacts they will over heat again and you will face the same problem.


It looks to me like it might be worthwhile to clean up and tighten all the connections while you are about it. Those ring terminals might not be making real good connection with the wires or each other.

loose connections were never an issue. the issue was that somewhere along the line, the terminal block was overtightened, and the block cracked. the upper right stud was broken off of the terminal block and was floating around inside the junction box. i'ver been in posession of this lathe for less than a month now, and for all i know the block may have been cracked since it was new back in 1994. the last things i did before it shorted out were to replace the belt and run it back and forth a bunch of times to clean out the screws. the combination of these may have been enough to move the wires enough so that they arced. the terminals were all tight, and will be cleaned and tight when i put them back. there's no question that it's a little dirty, but the connections are all bright and shiny.

Peter.
01-13-2013, 10:01 PM
If you use it like that kitten will die and the world will stop turning, spin backwards and we'll all be flung off into space!

P.S. that might be sarcasm...

I would insulate the leads right up to the crimp rings, fix the loose red lead to an adjacent lead with a small cable tie to hold it in place, cut a short piece of rubber hose that will screw onto the stud end to hold it off the casing, tape it all over and close the lid.

wierdscience
01-14-2013, 03:01 PM
I've had more than one of those plastic/bakelite block break,don't count on finding replacements they aren't too common over here.
If you wanted to do a proper job of it,got to Home Depot or Lowe's,back in the electrical section near the tools they will have wire marking labels.You can draw your own connection diagram and mark each wire accordingly.Then just use short brass machine screws and nuts to make the connections,insulate with rubber tape and close it up.That's the way it's been done since the last ice age never fails.

Fasttrack
01-14-2013, 03:12 PM
I've had more than one of those plastic/bakelite block break,don't count on finding replacements they aren't too common over here.
If you wanted to do a proper job of it,got to Home Depot or Lowe's,back in the electrical section near the tools they will have wire marking labels.You can draw your own connection diagram and mark each wire accordingly.Then just use short brass machine screws and nuts to make the connections,insulate with rubber tape and close it up.That's the way it's been done since the last ice age never fails.

Yep. Or you can use wire nuts or you can use those crimp connectors; we always called them "Blackburn sleeves" ("Blackburn connectors" referred to those side by side type splices for big power lines). They're a copper sleeve that you crimp on using a special tool and then snap a plastic cap over them.

e.g. http://electrical.hardwarestore.com/14-46-wire-connectors/copper-crimp-sleeve-connector-644894.aspx

I've seen motors in very harsh environments with lots of vibration, weather, large temperature swings, etc with wire nut connections and rarely have a problem. I've never seen a problem with the crimp connectors. The terminal blocks are good for the factory guys - makes it easy to set the machine up for 120 or 220 volts but once you know how you're going to run it, there's no need for the block.

lost_cause
01-14-2013, 05:24 PM
i put it back together a few hours ago. i put the terminal block back in and used the 5 good lugs. the remaining connection i made with a small bolt and nut, well covered in electrical tape. i'd like to be able to replace the terminal block, just to make it easier to switch to 120v, on the off chance i ever needed it. doubtful, but i always try to cover all my bases if possible. i'm telling myself that i may eventually make a replacement block sometime, but with the motor already being 18 years old, odds are it will quit before i make it. i'm amazed that those terminal blocks aren't more common and standardized. the one motor shop and one electrical supply house in the 50 mile radius say they are oem only, so they can't get them.

EVguru
01-14-2013, 05:28 PM
If it were my motor I'd either make a new terminal assembly from a piece of Tufnol, or I'd splice in a new set of long leads and bring them out to an external terminal block.

Lew Hartswick
01-14-2013, 05:39 PM
I don't see how anyone could see enough in that picture to even guess as to
the problem. :-(
...lew...

EVguru
01-14-2013, 05:43 PM
I don't see how anyone could see enough in that picture to even guess as to
the problem. :-(
...lew...

Get your monitor fixed or your eyes tested.