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New to me Hartford Mill

Susquatch

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@Susquatch : can you make a custom pulley?

I've done it before. Made a big pulley for a large 100 hp flail mower. Turned out great but...... the bar I made it from cost a fortune and I ended up with a barrel of swarf. Probably the most swarf I ever produced on any job.

The Keyway would be an issue too. Never tried broaching and don't have the tools for it.

But you make a good point. If I found a bigger pulley than I need, I could always turn it down. Prolly need to stay away from castings too.
 

Susquatch

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I've been noodling this problem for a few days now.

I ran across a 7/8 shaft 4 groove pulley on ebay for a myford lathe. It's expensive especially when shipping from the UK is factored in. I'm guessing it's no good to me anyway because it scales like a 3/8 belt if the photo is right. But the pulley has a shoulder at the motor end which got me to thinking a bit more along the lines of @Brent H's suggestion.

Screenshot_20210916-111536_eBay.jpg

Why couldn't I machine off the smallest groove on my existing pulley to make a stub like that. It would leave me with only 3 grooves of adjustment - all a bit faster than original, but as @Dabbler suggested a while back with the back gear issue, I have a VFD and a VFD rated motor so the truth is that the missing adjustment groove is not really a problem. Most likely, I'll put the belt on the second highest speed groove and never move it anyway!

In fact, why bother machining off the small groove? Just push the pulley back on the shaft one groove and go! And yes, I have confirmed that it easily fits the housing when I do that.

I might need a longer belt, but 1/2" v-belts are dirt cheap and available everywhere - I even saw a variety of v-belts at the convenience store!

I'll keep looking for a pully with a motor side shoulder like the one in the photo above, but the truth is that this issue is now behind me.
 
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Susquatch

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Got a little impatient about waiting for the new timing belt and decided to call MSCDirect to check on it. Glad I did. Apparently my order is stalled due to a component shortage. No ETA available. *#@/&% !!!

So,....... I think I'll put the head back together with the old timing belt, offset the pulley as per the post above, and then see if the current drive belt fits or if I need a longer one. Either way, I'll soon be able to see how it runs. Maybe after using it a bit, I'll be able to make a final decision on which mill to keep. That would be so nice!
 

Susquatch

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Have you tried taking the belt to auto value they have a good assortment of them

Are you talking about the drive belt or the timing belt?

The drive belt is available darn near everywhere in one inch increments (1/2 inch in a few places). I am not thinking that it will be a problem.

The timing belt is a whole nuther kettle of fish. It's an oddball.
 

Tom O

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I’m just saying that out here in Calgary they have a vast assortment of belts and sizes.
In what way is it a oddball?
 

Susquatch

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I’m just saying that out here in Calgary they have a vast assortment of belts and sizes.
In what way is it a oddball?

It isn't a standard width or pitch. Apparently, most timing belts have wider teeth than grooves. Prolly because the pulley is metal and stronger than the belt. But that's just a guess. Mine is 50/50. Anyway, all the standard belt makers say they don't make that style timing belt anymore. I was so thrilled when Bando (the original maker) said they would special build me one - so I ordered two. Quite disappointed that they were not able to follow through.
 

Susquatch

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Wonders never cease. MSC called me just now. I gather they leaned on Bando a bit (but that is reading between the lines), and Bando is going to expedite two belts using a stronger specification but same dimensions, then ship to MSC, who will ship to me that same day with tracking. Happy again!

But I'm still gunna assemble the Hartford this weekend (longer drive belt arrives on Saturday) with the old parts for evaluation......
 

Susquatch

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Moved the VFD to the Hartford Motor today. Man is that motor ever smooth!

But the pulley introduces a bad vibration at 60Hz. Prolly caused by the extra grub screws I installed. It's ok at 55 and below as well as 65 and above.

Guess I'll be taking a closer look at that thread on balancing a 4 jaw chuck.......
 

YYCHM

(Craig)
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Moved the VFD to the Hartford Motor today. Man is that motor ever smooth!

But the pulley introduces a bad vibration at 60Hz. Prolly caused by the extra grub screws I installed. It's ok at 55 and below as well as 65 and above.

Guess I'll be taking a closer look at that thread on balancing a 4 jaw chuck.......

Is that with or without the belt installed? Just wondering how you isolated it down to a pulley imbalance? 60 Hz should give you the motors rated RPM.
 
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Susquatch

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Is that with or without the belt installed? Just wondering how you isolated it down to a pulley imbalance? 60 Hz should give you the motors rated RPM.

Sorry, my previous post was a bit misleading. The Motor was sitting on the bench not on the mill. I ran it with and without the pulley. No belt yet.

The VFD also causes a bit of a whine in the motor that I don't like. I imagine it is related to the waveform.
 

Dabbler

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All motors whine when using a VFD. In very large installations they have simulated sine wave types that are quieter, but there's still a whine...
 

YYCHM

(Craig)
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Sorry, my previous post was a bit misleading. The Motor was sitting on the bench not on the mill. I ran it with and without the pulley. No belt yet.

The VFD also causes a bit of a whine in the motor that I don't like. I imagine it is related to the waveform.

Does the vibration occur with or without the pulley?
 

Susquatch

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All motors whine when using a VFD. In very large installations they have simulated sine wave types that are quieter, but there's still a whine...

I see. I never noticed it on the BP. Sounds like some research is warranted. Maybe I can smooth out the waveform with some CL filters.
 

John Conroy

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The noise you describe can be reduced to almost nil if you change the carrier frequency setting on your vfd. What brand of vfd are you using? I have set up a Huanyang, a Teco and a no name Chinese one and they all have the ability to change carrier frequency. Factory setting are usually around 5K HZ. That makes the sound within normal human hearing range. If you set it to above 12K HZ it will make the sound frequency at the high end of normal hearing. Some people can hear sounds up to 20K HZ but as we age our ability to hear high frequency sounds diminishes.

There are a couple of other vfd parameters you could look at that might improve smoothness. Check out the excellent YouTube video series by Clough42 where he installed a Teco vfd on his lathe.


He also did a video on vfd start/stop time tuning that's interesting

 
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Dabbler

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I'd just like to add to @John Conroy comments that each motor may have a resonant frequency where the whine is greater, or another node that is a lot quieter, so don't be afraid to try a wide range of frequencies to find the best 'quiet spot'. My TECO went to 20 KHZ, but I got more heat generated at low speeds, so I found for my mill, that the quietest spot with acceptable heating was at 12KHz.

- Those Clough42 videos are really a must-see for anyone starting out with a VFD.

I have none of the filtering Clough42 has installed, and mine works fine, but I will be adding line filtering. Output filtering as he suggests will also attenuate some of the whine as well.
 

Susquatch

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The noise you describe can be reduced to almost nil if you change the carrier frequency setting on your vfd. What brand of vfd are you using?...... Factory setting are usually around 5K HZ. That makes the sound within normal human hearing range. If you set it to above 12K HZ it will make the sound frequency at the high end of normal hearing. Some people can hear sounds up to 20K HZ but as we age our ability to hear high frequency sounds diminishes.

There are a couple of other vfd parameters you could look at that might improve smoothness. Check out the excellent YouTube video series by Clough42 where he installed a Teco vfd on his lathe.


I have a Teco L510 and a VFD Rated 2hp 220V 3ph motor. I've watched all the Clough42 videos on VFDs and a few dozen others. Also read the manual cover to cover. I agree that changing the carrier frequency might address some of the whine but I sort of doubt that is what I'm hearing. My carrier frequency is set to 4k. Trouble is that I know I can't hear above 2k at my age. I get my hearing checked regularly because I have significant hearing loss. I've had my ears checked again just a few months ago. I have hearing aides that are tuned to amplify sounds from 800hz up and no matter how much they amplify, they cannot make my ears hear what they cannot hear. Even when I was young I didn't hear above 8k or so. On the other hand, I do hear subsonic tones well below 60Hz that the vast majority of others don't hear. I'm sort of like an elephant in that way.

Anyway, according to my old audio frequency generator, I would say that the whine that bothers me is around 1600 Hz. Next time my wife goes out there, I'll ask her if she hears anything at higher frequencies.

The other point is that the whine is only there at certain motor speeds. If it were a carrier noise, I would think that it should be present across the whole speed range.

As @Dabbler points out, there is also the possibility that I have some line noise. My current temporary wiring is just solid core unshielded Romex. So it is possible that my problem might be line noise instead that is broadcasting rf to my hearing aides, or perhaps creating audible resonance in the hardware somewhere. That what I meant previously when I mentioned adding CL filters.

I don't really have time to chase that down right now. But I do have a pretty complete set of instrumentation (100Mhz storage oscilloscope, waveform generators, frequency generators, signal injectors, etc) that I can use to chase the problem down with and it is an area in which I have experience. Hopefully it will help.
 

Susquatch

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Is that with or without the belt installed? Just wondering how you isolated it down to a pulley imbalance? 60 Hz should give you the motors rated RPM.

My wife and I drove to Kitchener and back yesterday so I had very little time to play. However, I did take a half hour before bed to put the top housing on the motor with a new longer drive belt to check adjustment clearance. I couldn't resist running the motor. The damping inherent in the drive belt has almost clobbered the vibration.

My wife came out to the shop and I ran it for her too. That 4k scream made her practically claw her way through the wall of the shop.

If I get some time today, I plan to tune the VFD a wee bit. At a minimum I'll increase the carrier freq till she can tolerate it. But what I really want to do is switch to vectorless control.

Last night I spent a bit of time looking for shielded power cable for the VFD to Motor wiring. That was no piece of cake. I ended up frustrated. I only need about 8 ft of it. Where do you guys find that stuff?

Btw, I found this video explaining the virtues of various alternative wiring designs. I liked it.

 

Susquatch

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I did a little more VFD tuning today.

I could not get SLV to work properly until I discovered that my modulation was set to 2-phase Pulse Width Modulation. My manual, says that's the factory setting. Go figure. Anyway, changing that to 3phase PWM cured a whole host of issues and also allowed me to run SLV.

Between adding a belt, upping the carrier freq to 12khz and changing to 3ph PWM & SLV, she purrs like a kitten.

There is still a low freq noise there that happens below 43hz, but its totally tolerable. Maybe I can fix that too with additional tuning. We will see.

In the process of doing all that, I noticed that the low/hi speed spindle clutch actually raises and lowers the spindle pulley stack too. With my current motor pulley position, the belts line up nicely when the spindle pulley is down, and it's offset about a 1/4 inch when it's up. I don't like that. So I think I'll steal back half of the 1/4" I thought I could buy for the keyway and split the difference for the clutch as probably originally intended rather than using any of it for the pulley Keyway.

FWIW, I think this discrepancy explains the 1/4 difference between my measurements and @Dabbler's. My spindle pulley was probably down while his was up when measured.

Crap!
 
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