What is there to figure out?? Better components simply cost more to manufacture than poor quality components and quality control adds costs that are not passed on to consumers from companies with little quality control.?

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Jerry F. ??????????????????????????????????????????

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From: [email protected] [mailto:[email protected]] On Behalf Of davesmith1800
Sent: Sunday, July 14, 2024 7:59 AM
To: [email protected]
Subject: Re: [7x12MiniLathe] Mini lathe DC motor longevity

?

Interesting replacement.

I do not here of any one changing brushes.

I do know the type and size of brushes the use on mini lathe motor will last 1,000 to 3,000 hours. Items like sewing machines and treadmill mills usecsamevtype motor.

A squire cage motor has life of over 20,000 because of the ball bearing. Most found on older mini lathes

The industrial DC motor brush life between changse is 7,000 to 10,000 hours. Probably to costly for mini lathes

FYI on oil run motors like the homes AC will last about 20 years and has a Chinese made oil capacitor needs to change every 5 to 7 years American will last 12 to 20 years. This is available and can be same category as a AC motor. Do have number of hours just years

So I look at the problems member are having and wonder why and can be fix and low cost.

Dave

FYI
On electronics control boards
Most time it is a manufacturer error, over heating, voltage stickers or drit on the board.
My example is clock my wife and self purchase 32 years ago and use everyday is still running or 280,000 hours and still going

On Sun, Jul 14, 2024 at 06:25 AM, <jtpikitech8@...> wrote:

On my HF mini lathe the controller failed but I had been saving a treadmill motor (110 DC permanent magnet motor with a large flywheel and small diameter poly groove belt pulley) to provide more overall torque. This motor did require a mounting bracket as it is to large for the under bed location. I also drilled a small hole parallel to the motor shaft half into the pulley and half into the shaft and drove a pin in to prevent the flywheel coming off when the motor started. It was only secured with a bolt thread in the treadmill. I have a shop made poly groove pulley on the spindle instead of the OEM toothed belt input pulley. The DCPM motor maintains high torque with low RPM when it receives less DC voltage. It's range is 0-110 VDC and this is provided by an inexpensive SCR based AC lamp dimmer circuit and a full wave bridge rectifier (Amazon) and a DPDT (6 terminal) switch provides reverse. This setup does not use the change gears and does not drive the lead screw so I feed the cross slide manually. I do plan to redesign it soon to include a jack shaft with a toothed belt to drive the OEM input pulley and therefore the change gears, the lead screw, and the hi/lo range gears and this should allow much slower RPM with high torque. Since I acquired the motor for free and built the hardware to mount it my only cost was for the SCR dimmer, the rectifier, and the DPDT switch.
--
JTPIKITECH

?

?

Interesting replacement.

I do not here of any one changing brushes.

I do know the type and size of brushes the use on mini lathe motor will last 1,000 to 3,000 hours. Items like sewing machines and treadmill mills usecsamevtype motor.

A squire cage motor has life of over 20,000 because of the ball bearing. Most found on older mini lathes

The industrial DC motor brush life between changse is 7,000 to 10,000 hours. Probably to costly for mini lathes

FYI on oil run motors like the homes AC will last about 20 years and has a Chinese made oil capacitor needs to change every 5 to 7 years American will last 12 to 20 years. This is available and can be same category as a AC motor. Do have number of hours just years

So I look at the problems member are having and wonder why and can be fix and low cost.

Dave

FYI
On electronics control boards
Most time it is a manufacturer error, over heating, voltage stickers or drit on the board.
My example is clock my wife and self purchase 32 years ago and use everyday is still running or 280,000 hours and still going

On Sun, Jul 14, 2024 at 06:25 AM, <jtpikitech8@...> wrote:

On my HF mini lathe the controller failed but I had been saving a treadmill motor (110 DC permanent magnet motor with a large flywheel and small diameter poly groove belt pulley) to provide more overall torque. This motor did require a mounting bracket as it is to large for the under bed location. I also drilled a small hole parallel to the motor shaft half into the pulley and half into the shaft and drove a pin in to prevent the flywheel coming off when the motor started. It was only secured with a bolt thread in the treadmill. I have a shop made poly groove pulley on the spindle instead of the OEM toothed belt input pulley. The DCPM motor maintains high torque with low RPM when it receives less DC voltage. It's range is 0-110 VDC and this is provided by an inexpensive SCR based AC lamp dimmer circuit and a full wave bridge rectifier (Amazon) and a DPDT (6 terminal) switch provides reverse. This setup does not use the change gears and does not drive the lead screw so I feed the cross slide manually. I do plan to redesign it soon to include a jack shaft with a toothed belt to drive the OEM input pulley and therefore the change gears, the lead screw, and the hi/lo range gears and this should allow much slower RPM with high torque. Since I acquired the motor for free and built the hardware to mount it my only cost was for the SCR dimmer, the rectifier, and the DPDT switch.
--
JTPIKITECH

The speed depends on the material and the diameter.?

I have turned a piece of 3 inch diameter stainless down to make a ER 32 collet chuck.?

I don’t take budget cuts.?

On a recent part I took 0.040 from the diameter on a piece of 1 inch diameter steel.?

John?

On Sun, Jul 14, 2024 at 2:05?PM davesmith1800 via <davesmith1=[email protected]> wrote:

That is great news.
I have been reading a lot motors troubles on mini lathe.
I could be speed the min lathe runs at is the different.

Do you due most work on higher motor speed?

Dave

On Sun, Jul 14, 2024 at 11:36 AM, John Mattis wrote:

I got my Speedway mini lathe in June of 2002 and have used it extensively with no motor problems.

I did have to have the control box repaired about three?years ago.

John

On Sun, Jul 14, 2024 at 9:37?AM davesmith1800 via <davesmith1=[email protected]> wrote:

I was looking internet on longevity of dc motors and founds you may like read.
The first is the most common motors for mini lathes.
The second link is on industrial DC motor they very expensive for mini lathes.
If read it said same busily thing I did on my last post
Mini lathe burshes latest 1,000 to 3,000 and industrial motor 7,5000 hours.
But some may like reading.

.

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?

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?

I got my Speedway mini lathe in June of 2002 and have used it extensively with no motor problems.

I did have to have the control box repaired about three?years ago.

John

On Sun, Jul 14, 2024 at 9:37?AM davesmith1800 via <davesmith1=[email protected]> wrote:

I was looking internet on longevity of dc motors and founds you may like read.
The first is the most common motors for mini lathes.
The second link is on industrial DC motor they very expensive for mini lathes.
If read it said same busily thing I did on my last post
Mini lathe burshes latest 1,000 to 3,000 and industrial motor 7,5000 hours.
But some may like reading.

.

?

?

On my HF mini lathe the controller failed but I had been saving a treadmill motor (110 DC permanent magnet motor with a large flywheel and small diameter poly groove belt pulley) to provide more overall torque. This motor did require a mounting bracket as it is to large for the under bed location. I also drilled a small hole parallel to the motor shaft half into the pulley and half into the shaft and drove a pin in to prevent the flywheel coming off when the motor started. It was only secured with a bolt thread in the treadmill. I have a shop made poly groove pulley on the spindle instead of the OEM toothed belt input pulley. The DCPM motor maintains high torque with low RPM when it receives less DC voltage. It's range is 0-110 VDC and this is provided by an inexpensive SCR based AC lamp dimmer circuit and a full wave bridge rectifier (Amazon) and a DPDT (6 terminal) switch provides reverse. This setup does not use the change gears and does not drive the lead screw so I feed the cross slide manually. I do plan to redesign it soon to include a jack shaft with a toothed belt to drive the OEM input pulley and therefore the change gears, the lead screw, and the hi/lo range gears and this should allow much slower RPM with high torque. Since I acquired the motor for free and built the hardware to mount it my only cost was for the SCR dimmer, the rectifier, and the DPDT switch.
--
JTPIKITECH

Don't forget about the difference in expected running times. Starter motors only run for a few seconds under a heavy mechanical load - most common motors run for much longer times under lighter mechanical loads.

Roy

Don't forget about the difference in expected running times. Starter motors only run for a few seconds under a heavy mechanical load - most common motors run for much longer times under lighter mechanical loads.

Roy

And if anyone isn’t aware, brushes have different hardness grades.? The trade off is soft brushes need replacing more often but don’t wear the commutator, and the opposite for hard ones.

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Of course our mini-lathes get so little use it doesn’t matter, ?as shown by Ralph’s 30 year old example that has plenty of brush left and zero commutator damage.

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Spring tension matters as well, as Jon pointed out it had failed in Ralph’s picture.? If it doesn’t press hard enough you get arcing & heat build-up which cascades until it all goes pear-shaped.? As happened.

?

Tony

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From: [email protected] <[email protected]> On Behalf Of davesmith1800 via groups.io
Sent: Wednesday, 10 July 2024 12:24 AM
To: [email protected]
Subject: Re: [7x12MiniLathe] how to.inspect.motor?

?

When doing a lot motor repair it hard to get the parts.?
I even took brushes and file down to fit.?

I had older motors for parts.
Getting parts has always been a problem. FYI Ebay can easier to find parts. Today if I have problem with motor I just replace the motor only because of size.?

Dave?

On Mon, Jul 8, 2024 at 06:48 PM, Ralph Hulslander wrote:

Here is the adjusted brush holder:

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It's not straight so maybe I'll try to adjust. I'll try to get the wood closer to actual dimensions.

You can see what happened to the set screw. Also the holder is no longer set; it can slide in and out.

Possibly the brush will hold it in place.

?

Ralph

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On Mon, Jul 8, 2024 at 9:32?PM Roy via <roylowenthal=[email protected]> wrote:

Here's more detail than you probably want about testing ball bearings;

?< >

Realistically, on these small bearings all that's needed is a visual inspection for obvious damage & checking that they rotate smoothly with thrust applied in both directions. If you decide to replace one, make sure you don't apply pressure on the outer race while pressing the inner race onto the shaft. Putting pressure across the balls damages the bearing by making little dents (brinelling) on the contact surfaces.

Roy

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Had a crash awhile back while using a milling bit on my Grizzly 7x12 mini lathe.? Motor stalled and fuse blew.? I put in a new fuse, but motor won't run.? Are there any other circuit breakers/fuses that could be the problem?? Or, am I looking at a blown motor?