Cutting threads on a motor shaft

[Tom Brown]

It's time to rebuild our hot tub pump. I think it's a 3hp Pentair.

To get the front bell off, I had to beat on it a bit (it was corroded). I ended up hitting the tip of the motor shaft a few times with a bronze hammer and it mushroomed a bit.

I figured it would be no problem chasing the thread out but it's proving to be nasty.

I've got a 25 year old set of carbide dies. Most of them are unused. The 3/8-16 die won't seem to cut the shaft steel.

Am I going to need a better quality die for this job? Are motor shafts too hard for carbide?

 

[Joker]

Did you fix the worn out headrest pads?

 

[Tom Brown]

Oh yeah. I got the correct ones from the factory and talked them into selling them to me for 20 bucks each since the tub is so long obsolete. lol!

 

[racered]

You beat on your shaft and it swole up??
really, use a small grinder to radius the oversized thread,
then a thread file to clean up the thread ,easy does it now. Pull this off and you will be the hero of the the thrifty few.

 

[Tom Brown]

It's not very swollen. In fact, it's barely noticeable but the impeller won't go on.

I hadn't thought of using a thread file. I'll give that a go. Thanks!

I'm kind of surprised the die won't chase out the thread.

 

[OCMerrill]

You sure fuck up allot of threads.

The shaft it's self may not be hard but what your fighting may be a nitride or a hard chrome coating. Done so the shaft seals don't wear a groove in the shaft. Your not going to cut either with a tap. File till fits or grind it down a little to eliminate the mushroom effect.

Hindsight...Plastic or brass hammer.

Hope this helps you out, asshole. :thumbsup

 

[soupersonic]

Are you sure about the thread size? I have done them before and most of them are a 7/16 Fine thread if i remember correctly.
Also im sure you know this, but make sure you change the pump seal

 

[soupersonic]

You sure fuck up allot of threads.

Hope this helps you out, asshole. :thumbsup

Classic material right there

 

[Rowboat]

Get yourself a tool called a NES1, it clamps on below the bad section of threads, tighten it up and wind it off. It will clean up the threads no problems!
I bought one years ago and use it all the time. If I remember correctly it was about 20 bucks.

 

[Flyinbowtie]

Rowboat I just went and looked at that tool. It is now on my list, thanks.

 

[Tom Brown]

You beat on your shaft and it swole up??
really, use a small grinder to radius the oversized thread,
then a thread file to clean up the thread ,easy does it now. Pull this off and you will be the hero of the the thrifty few.

Glory! The thread file fixed the threads to the point you would never know there was an issue. I ran the die over them to clean them up but I'm not sure it was necessary. The die threaded on like a nut on a fresh bolt.


Thanks, Ed. You da man! :thumbsup


I've saved enough money to go out for breakfast at the Sizzler next Sunday.

 

[Tom Brown]

The rebuilt pump leaks.

There is a drip every 5 or 10 seconds from the bottom of the pump housing. I replaced the seals, impeller, and motor bearings.

It seemed pretty straight forward. Everything fit properly, except the impeller but I cut it down about 1/8" to fit in the housing. The seal was snug in the motor housing and was a relatively tight friction fit into the impeller.

I've been told that skin oil can cause pump seals to leak. I definitely touched the ceramic portion of the seal with my fingers when I installed it. I wiped it with a clean cloth before putting the impeller in for the last time.

It's tough to tell where the water is coming from. The pump is too deep inside the hot tub to be able to see all sides from the access door. All I can see is that it's dripping off the bottom of the pump housing.

Any ideas? Another seal?

 

[Guest]

Any ideas?

Relocate to the Bahamas..:thumbsup

 

[Kachina26]

The rebuilt pump leaks.

There is a drip every 5 or 10 seconds from the bottom of the pump housing. I replaced the seals, impeller, and motor bearings.

It seemed pretty straight forward. Everything fit properly, except the impeller but I cut it down about 1/8" to fit in the housing. The seal was snug in the motor housing and was a relatively tight friction fit into the impeller.

I've been told that skin oil can cause pump seals to leak. I definitely touched the ceramic portion of the seal with my fingers when I installed it. I wiped it with a clean cloth before putting the impeller in for the last time.

It's tough to tell where the water is coming from. The pump is too deep inside the hot tub to be able to see all sides from the access door. All I can see is that it's dripping off the bottom of the pump housing.

Any ideas? Another seal?

Plant some jasmine around the hot tub and use the dripping water to irrigate it. The sweet smell of jasmine will be your reward!

 

[BDMar]

WE have been rebuilding Jacuzzi jet pumps for 35 years. The Y pump has a ceramic/carbon water seal (as does some Jabsco pumps). Bottom line is finger oil has never been a problem. The problem usually lies in the seal of the ceramic to the shaft. Usually an o-ring or some type of rubber holding the ceramic to the shaft. The next most common problem is the carbon side is very easy to chip or crack during assembly.