# Mill conversion to 3 phase



## David_R8 (May 8, 2020)

I started tearing apart the mill to do the motor swap to 1.5 hp 3ph.
I don't have a puller so I had to improvise with some all-thread couplers and 3/8" bolts which I used to jack to pulley off the shaft.
As I got close to getting it off the shaft I ran out of thread on the fully threaded bolts so I ran them back in and put the shouldered bolts in the other end.





The pulley was so tight I thought I was going to strip the threads. Even after heating it up with my propane torch it was a struggle to make it budge.






Finally got it off. Discovered what there was no keyway in the pulley, just a setscrew that seated in the keyway.

I think I'll be shopping for a new pulley as the bore is 15/16" and the new motor shaft is 7/8. I suppose I could bore it out and make a bushing but I have no means to broach the keyway.


----------



## YYCHM (May 8, 2020)

Lots of youtubes on manually broaching keyways on a mill or lathe.  I just did one on my lathe.






Doubling the HP eh.  You're gonna have to Hilti that mill to the floor now.


----------



## David_R8 (May 8, 2020)

@YYCHobbyMachinist I’d go for that except the pulley is steel. Think it’s possible still?

It’s 1.5 hp. I currently have 1 hp. I increased the hp to compensate for loss of torque at low speeds. 


Sent from my iPhone using Tapatalk


----------



## YYCHM (May 8, 2020)

David_R8 said:


> @YYCHobbyMachinist I’d go for that except the pulley is steel. Think it’s possible still?
> 
> It’s 1.5 hp. I currently have 1 hp. I increased the hp to compensate for loss of torque at low speeds.



Ooooops.  I interpreted the 3ph as 3hp.  Me Bad.

Should be able to broach steel manually, just going to be a LOT of very shallow cuts.

Maybe @RobinHood or @Tom Kitta can weigh in here.

Craig


----------



## trlvn (May 9, 2020)

Had the set screw galled the shaft and made it hard to remove the old pulley?

Are you looking for a single pulley or a 3-step?  Since you have the VFD, I'm guessing the multi-step pulley isn't really necessary?

If you were to bore and bush, how much 'meat' is there before cutting through the bottom of the smallest pulley?

Craig


----------



## David_R8 (May 9, 2020)

There was no galling that I could see or feel. I think it was just 40 years of never having been removed that was the issue. 

Boring shouldn’t be an issue because the motor shaft doesn’t extend much past the height of the bottom sheave.  
There’s lots of thickness to accommodate boring to accept a bushing. 

I’m inclined to look for a pulley the size of the middle sheave. The one thing that I’m concerned about is finding a new pulley that has a long enough shaft to be the same height so belt tracking isn’t affected. 


Sent from my iPhone using Tapatalk


----------



## francist (May 9, 2020)

If you’re thinking of sourcing local, try Troy Electric or the guys over on Bridge St — Osborne Mechanical?. Troy had a nice selection of steel pulleys when I needed one for my Keller. Western Equipment maybe as well.

-frank

failing that, you could always turn one on your lathe.....


----------



## David_R8 (May 9, 2020)

francist said:


> If you’re thinking of sourcing local, try Troy Electric or the guys over on Bridge St — Osborne Mechanical?. Troy had a nice selection of steel pulleys when I needed one for my Keller. Western Equipment maybe as well.
> 
> -frank
> 
> failing that, you could always turn one on your lathe.....



Thanks Frank, I wouldn’t have thought of Troy Electric. 
Western Supply was going to be my first stop. 

I may try turning a bushing and see how that goes. I have some 1.125” 1018 that would probably work ok. 


Sent from my iPhone using Tapatalk


----------



## YotaBota (May 9, 2020)

BOB's Motor Electric on David St would be another one to try (if open).


----------



## kevin.decelles (May 10, 2020)

When I did my conversion I sourced my pulley from Canadian knife maker supply . The pulley was a 2-3-4 and 7/8 bore

Not cheap, but did the job. Pulley was 85 or 90 bucks

Www.knifemaker.ca


Search for pulley


----------



## David_R8 (May 10, 2020)

I decided to make a bushing. 
Measurement indicated that I needed to go larger than the 1018 I had so went with some 1.25” 6061 aluminum. 
Bored out the pulley then turned the aluminum to match. 
Bored the aluminum to .875” to match the new motor shaft. 
Cut the key way using a 1/8” cut off blade laid flat in a tool holder. 
I didn’t bore the pulley deep enough so I have to fix that but I’m pretty happy with it. 


























Sent from my iPhone using Tapatalk


----------



## YotaBota (May 10, 2020)

Looks good, is the bushing press fit into the pulley?


----------



## David_R8 (May 10, 2020)

YotaBota said:


> Looks good, is the bushing press fit into the pulley?


Yes, it's a pretty snug fit on both. I can pull the pulley off but I can't easily remove the bushing without a puller. I may have to invest in one...


----------



## YYCHM (May 10, 2020)

Seems kind of odd that the pully has no keyway?  What does the pully set screw engage on your bushing to keep them from spinning?

I take it you cut the bushing keyway on your manual lathe.  Well done.


----------



## David_R8 (May 10, 2020)

YYCHobbyMachinist said:


> Seems kind of odd that the pully has no keyway? What does the pully set screw engage on your bushing to keep them from spinning?
> 
> I take it you cut the bushing keyway on your manual lathe. Well done.





YYCHobbyMachinist said:


> Seems kind of odd that the pully has no keyway? What does the pully set screw engage on your bushing to keep them from spinning?
> 
> I take it you cut the bushing keyway on your manual lathe. Well done.



Thanks, cutting the key way was a real challenge as the cutoff tool flexed and the sides of the key way were not parallel. Some file work corrected that. 

The set screw engaged the key slot on the old motor shaft. This time I’m going to drill a small dimple in the bushing for the set screw to seat into. 


Sent from my iPhone using Tapatalk


----------



## John Conroy (May 11, 2020)

Looks good, nicely done David!


----------



## David_R8 (May 11, 2020)

John Conroy said:


> Looks good, nicely done David!



Thanks, I appreciate that. It was a number of firsts for me. 
Boring
Working to a specific dimension 
Cutting a key way 


Sent from my iPhone using Tapatalk


----------



## John Conroy (May 11, 2020)

It's always great when a plan comes together.


----------



## David_R8 (May 15, 2020)

I took some time last night to connect the VFD. I used 14 ga THHN from VFD to motor. 
Motor is silky smooth after tweaking some setting on the VFD. I still need to source a 2K pot so that I can put the speed control on the mill. 
Sadly my bushing has about 30 thou runout so I need to remake it or shell out for a new pulley.  I think the problem is that the keyway at the bottom of the bushing is not as deep as the top so it's wedging the bottom out slightly.


----------



## John Conroy (May 15, 2020)

David I bought a large assortment of pots on Amazon. If you can wait for Canada Post to deliver one I'll send it to you. I'll never use all of them in this lifetime


----------



## David_R8 (May 15, 2020)

Gee thanks John! Do you have a 2K by any chance?


----------



## YotaBota (May 15, 2020)

David_R8 said:


> Sadly my bushing has about 30 thou runout so I need to remake it or shell out for a new pulley. I think the problem is that the keyway at the bottom of the bushing is not as deep as the top so it's wedging the bottom out slightly.


You could think of it as kissing a frog and the next one will be the princess. 

Great of John to offer help with the pot, if that doesn't work Queale is just down the street in the same plaza as Acklands.


----------



## YYCHM (May 15, 2020)

David_R8 said:


> Sadly my bushing has about 30 thou runout so I need to remake it or shell out for a new pulley.  I think the problem is that the keyway at the bottom of the bushing is not as deep as the top so it's wedging the bottom out slightly.



What does it measure without the key installed?  If that fixes the issue I'd be inclined to deepen the keyway.


----------



## David_R8 (May 15, 2020)

YYCHobbyMachinist said:


> What does it measure without the key installed?  If that fixes the issue I'd be inclined to deepen the keyway.


In fact I did not. I will do that and see how it measures out.


----------



## YYCHM (May 15, 2020)

David_R8 said:


> In fact I did not. I will do that and see how it measures out.



Measure the shaft while you're at it.  Maybe it's not the bushing that's the culprit.  Were you measuring off the bushing or the pulley?


----------



## David_R8 (May 15, 2020)

YYCHobbyMachinist said:


> Measure the shaft while you're at it.  Maybe it's not the bushing that's the culprit.  Were you measuring off the bushing or the pulley?


First measured off the straight part of the pulley shaft, then the bushing itself, at the top and as close to the bottom as I could get.


----------



## RobinHood (May 15, 2020)

David_R8 said:


> Sadly my bushing has about 30 thou runout so I need to remake it



Hi David, don’t give up just yet and go buy a new pulley. As has been suggested, find out where the runout actually is: the motor shaft (not likely since it seems to be a quality, new motor), or the pulley. It could be your bushing, but I see you turned OD and ID in one set-up, so it should run true.

should it be the motor shaft, make a new bushing with OD oversize (about 50 thou or so). Install bushing on shaft. Bolt the motor onto your mill table. Put a turning tool into the mill spindle. You could use a fly cutter with the tool installed up side down - check for cutter clearance (grind if required). Lock the spindle. Turn on the electric motor and skim off the excess material (so the OD fits the pulley) by feeding the motor bushing under the tool. After you are done, the bushing will run true on the OD and a true running pulley will also run true.

if the pulley is the problem, make your bushing ID undersize. Insert it into the pulley. Mount the pulley in your lathe (use a 4J and indicate the pulley OD to run true). Bore the ID to size (so it fits over the motor shaft). Cut the key way.

You should have eliminated the runout.


----------



## John Conroy (May 15, 2020)

Looks like the lowest is 5K ohms. My Teco vfd called for 5K and the Huanyang was 10k.







Sorry David.


----------



## David_R8 (May 15, 2020)

@John Conroy 
I just read my manual and I can use anything between a 1-5K


----------



## John Conroy (May 15, 2020)

Great I'll send you one


----------



## David_R8 (May 15, 2020)

John Conroy said:


> Great I'll send you one


I popped you a PM with my address. Thanks again!


----------



## YotaBota (May 15, 2020)

If the top of the bushing is tight and the bottom can be pushed out does that mean you have a taper?


----------



## David_R8 (May 15, 2020)

YotaBota said:


> If the top of the bushing is tight and the bottom can be pushed out does that mean you have a taper?



I think I I discovered the roots of the problem. 
The key way was not filed flat along it’s length so the key was pushing the bushing a bit out off centre. 
But somehow the bore in the pulley is not concentric. I’m not sure how that happened. 

I filed the key way flat and the key now fits flat without movement.
That said I think I have to turn a new bushing because to make the pulley concentric the bore will have to be enlarged. 


Sent from my iPhone using Tapatalk


----------



## YYCHM (May 17, 2020)

David_R8 said:


> I think I'll be shopping for a new pulley as the bore is 15/16" and the new motor shaft is 7/8. I suppose I could bore it out and make a bushing but I have no means to broach the keyway.



Hey,  I just realise that I have a steel 3 sheave pully with what appears to be a 0.872 bore.  It's currently bushed to 5/8".  Sheave diameters at the root appear to be 55mm, 80mm, and 105mm approx.  Strange arrangement, the pulley doesn't have a keyway but it has three set screws in the root of the smallest sheave.







Would that work for you?

Craig


----------



## David_R8 (May 17, 2020)

@YYCHobbyMachinist Thanks for thinking of that Craig.

I actually had another go at the pulley and bushing today.

I used the 4-jaw so I could dial the pulley in nice and true. I chucked it up, called upon Abom79, popped my indicator into the largest pulley groove and got it under a thou of runout in about two minutes. 
Holy moly! The snout of the pulley was wobbling like a weeble! Somehow, I managed to bore the thing off-centre 

I remeasured the bore depth and decided to go 3/8" deeper so I could get the pulley coplaner with the idler pulley.

Commence making horrible cast iron mess. I really hate machining cast iron.

Got it bored correctly this time. Time to make a new bushing.
Still using the 4-jaw I chuck up a length of stock. Dialed it in easy. I'm liking this chuck!
I didn't have to take much off the 1-1/8 aluminum to get a nice, slip fit in the pulley. I made sure to take light cuts to avoid heating up the aluminum and throwing off my test fits. A few passes and all done.

Time to bore. Worked my way up to the biggest bit I have, a 5/8' then back to the boring bar till I hit .0875 bang on. 

I decided to not cut a key way. Instead I sawed a slot and then filed it to fit the key like a glove!

Fitted it up and gave it a test run. Smooth as butter, no wobble, no vibration!

Popped the belt on, and the only thing I can hear is horrible grinding from the idler puller. 

Pull that off and discover that the bearings are completely toast. After only 30 years of service with likely zero maintenance. 

So ordered new bearings. For reference there are two 47mm OD, 20mm ID X 14mm thick bearings.

Was a good way the end the day.
Thanks for reading!


----------



## thriller007 (May 23, 2020)

what VFD are you using?


----------



## David_R8 (May 23, 2020)

thriller007 said:


> what VFD are you using?



This one. 

https://www.emotorsdirect.ca/item/t...ht_sourced=3.5&custcol_sca_category_sourced=3


Sent from my iPhone using Tapatalk


----------



## thriller007 (May 24, 2020)

David_R8 said:


> This one.
> 
> https://www.emotorsdirect.ca/item/t...ht_sourced=3.5&custcol_sca_category_sourced=3
> 
> ...


What do you figure you will have into the motor and vfd project in total?


----------



## David_R8 (May 24, 2020)

thriller007 said:


> What do you figure you will have into the motor and vfd project in total?


Right around $600. 
I had all the wire and miscellaneous bits. @John Conroy kindly sent me a 10K pot (it arrived on Friday, thanks very much @John Conroy !)

I chose to go the new route because:
a) used three phase motors are virtually non-existent where I live
b) I wanted a bolt on fit so needed a 145 frame
c) The video series by Clough42 is a step by step install of the 1 hp version of the same VFD


----------



## YYCHM (May 24, 2020)

How much are you into that mill for now?

Ya, I know..... don't ever add her up cuz you'll soon discover that you're eating $10/lb venison


----------



## David_R8 (May 24, 2020)

YYCHobbyMachinist said:


> How much are you into that mill for now?
> 
> Ya, I know..... don't ever add her up cuz you'll soon discover that you're eating $10/lb venison



So far I have a set of $2000 T-nuts, and a $500 bracket 


Sent from my iPhone using Tapatalk


----------



## David_R8 (May 26, 2020)

A bit of an update on the motor conversion. 
When I fired everything back up the idler pulley bearings were making an awful racket. 
I removed the pulley and pressed out the bearings. They were open cage and completely full of dirt and grime from 30 years of use. 

Took some measurements and ordered new sealed, lubricated bearings which arrived today. 
Put it back together last night. What a difference the new bearings make. There’s only slightly more noise than from the just the motor alone. Very happy with the result.


----------



## David_R8 (May 27, 2020)

More progress last night.
I was struggling with the VFD programming as I could not get the forward/stop/reverse switch to work correctly. I could only get forward or reverse.
I reached out to a member on Hobby-Machinist and got detailed instructions on how to program a specific part of the many configurations.
After a couple of tries I got it right. Now I have a forward and reverse switch! So darn cool!


----------



## YotaBota (Jan 23, 2021)

How's the mill running?
Did you notice any difference in the finish or anything else going from single to 3 phase?


----------



## David_R8 (Jan 23, 2021)

YotaBota said:


> How's the mill running?
> Did you notice any difference in the finish or anything else going from single to 3 phase?



It runs fantastic. The difference between single phase and three phase is palpable. The single phase motor felt ‘notchy’ if that makes any sense whereas the three phase motor is smooth as silk.


----------



## YYCHM (Jan 23, 2021)

David_R8 said:


> It runs fantastic. The difference between single phase and three phase is palpable. The single phase motor felt ‘notchy’ if that makes any sense whereas the three phase motor is smooth as silk.



That's what I found as well.  The 3 phase was smoother and quieter.


----------



## YotaBota (Jan 23, 2021)

Good to hear it was worth doing. I'm dealing on another lathe that I'm told is 3phase and was wondering if it was worth going the VFD route. If I get the new lathe I'll start a thread but for now I don't want to say much in case I jinx it.


----------



## David_R8 (Jan 23, 2021)

I’m not saying a word about your new lathe! 
Oh crap... I just did. [emoji16]


----------



## YotaBota (Jan 23, 2021)

DOH!!!!!!! Where's my gun!!!!


----------

