Thornton mechanical lab surface grinder

[Batmanacw]

There is a bit more too it than has been discussed. Further help would require you being willing to disassemble the spindle and post pictures of the spindle parts (including both bearings (both sides of each). Lots of details are involved in assembly of a precision spindle.

It's good to read the spindle taper runout was very very little.

I'm pretty sure I've got the spindle assembled right. I'm not risking the bearings by removing them. The pictures above had the spindle in them.

I'm going to track down the motor vibration issues tomorrow and get a different v belt. My alignment wasn't the best so I'll fix that while I'm at it.

I think things will improve more in the morning.

 

[Batmanacw]

I'm going to start looking for a new motor. I have the pulley alignment perfect and nice easy belt tension. The motor vibrates pretty badly even with no belt on it. I want to find a nicer smoother running motor and see if it helps. The finish is the only issue. Accuracy is fine and it runs as smooth as its every run.

It's funny the problem Harbor Freight motor is USA made.

 

[Batmanacw]

I wonder if the fact that I'm running a single phase motor is causing a less smooth finish.....

 

[Lo-Fi]

Single phase motors do "hum", but it sounds like this one is plain old out of balance. Decent single phase motor without vibration issues should sort this, I'd have thought. Belt and braces... Can you put a hefty flywheel on it?

 

[Bob Korves]

Try taking the pulley off the motor and see if it still has vibration (if you have not done so already...)

 

[Batmanacw]

Try taking the pulley off the motor and see if it still has vibration (if you have not done so already...)

It still vibrated pretty good. I couldn't tell the difference.

 

[Bob Korves]

Does the shaft have runout when it spins?

 

[Batmanacw]

Does the shaft have runout when it spins?

The motor needs to go whether it's just out of balance or the shaft runs out. I'm not putting an indicator in there to find out.

 

[extropic]

Right on! No point in investigating the problem when you've already decided on a solution.

 

[pontiac428]

Kenny Rogers said it was important to know when to polish that turd, know when to bin it, something like that. There's nothing wrong with committing to buy a quality motor when you know you've got a moist fresh one in your hands. A good 1-hp Baldor will run at a smooth whisper for sure, without breaking the bank. I think that's a fair plan, even if it skips some of the empirical steps of formal troubleshooting. That's a liberty reserved for a man who owns his own shop.