Author Topic: Spline/noisy milling  (Read 90 times)

Carpenter84

Spline/noisy milling
« on: June 06, 2019, 10:22:59 PM »
I've been setting up to make an adapter plate to swap my single phase motor out for a 3 phase.
Since the motor is off, I took the opportunity to swap the bearings inside the pulley as they've gone bad. And since I have the pulley housing off, i started looking at the fit between the spline shaft and bushing. There's play back and forth. I asked about this in a previous post, and it was determined as normal.
However, when I side mill with an end mill, or do any milling with an interupted cut, the mill is VERY noisy. Almost like a banging for each pass of a tooth.
The best i can figure is the noise is eminating from the play in the spline banging back and forth. Maybe?

Since I'm at the spline connection, is there anything I can do? Or to investigate where the noise could be before I put new bearings in and put it back together.
Shawn

First 9x42 column mill,
Enterprise 10x28 lathe,
Ko Lee 6x12 surface grinder,
Airco dip/stick 160 welder,
Fully stocked wood shop.

f350ca

Re: Spline/noisy milling
« Reply #1 on: June 07, 2019, 07:42:45 AM »
Your probably staring down a deep rabbit hole Shawn.

Greg

chips and more

Re: Spline/noisy milling
« Reply #2 on: June 07, 2019, 08:13:04 AM »
Sounds like you found the noise. Can you get parts for the mill? Now remember, I didn’t say this! But you could try and reposition the spline shaft in a different order. It could fit better doing that. But the fit sure won’t last long. Could have some peace and quiet for a while? Or more problems? Maybe back to the get some replacement parts idea.

chips and more

Re: Spline/noisy milling
« Reply #3 on: June 07, 2019, 08:18:24 AM »
Once you get that VFD hooked up. Then hopefully you can find that “sweet spot” (motor speed) in the drive and maybe avoid wear, noise and all that.

4GSR

Re: Spline/noisy milling
« Reply #4 on: June 07, 2019, 08:51:15 AM »
I find it necessary to speed up the RPM's and sometimes increase feed rate too. To reduce the "banging" noise from the spline.  Eventually, you will wear out the spline and the two pieces will have to be replaced.  Maybe in the next two lifetimes, this will happen. 
Ken

woodchucker

Re: Spline/noisy milling
« Reply #5 on: June 07, 2019, 09:45:38 AM »
So I have the same issue. When I put the mill back together I had used a belt that was stiff, with kevlar. it made lots of noise because the belt was so stiff, it slapped the spline back and forth.

I replaced it with a link belt and it went away. I then replaced the link belt with cog belt.. super smooth, but still noisy from the cogs.

I have a spring loaded brass plug on my mill (Clausing 8520) that also helps lower the slapping, I tightened it up a lot and it helped to stop the slapping while milling.

it presses against the spline to remove play and prevent hysteresis.

Jeff
Clausing 8520   SB Model 9a - power hacksaw, Milwaukee band saw in a table.  Delta Rockwell Surface Grinder (not online yet .. being rebuilt where am I going to stick this)
For pics: https://imgur.com/user/woodchucker/posts

Carpenter84

Re: Spline/noisy milling
« Reply #6 on: June 07, 2019, 11:01:29 AM »
As far as the wear is concerned, in a previous thread I think it was determined that everyone's mill has this play. I wouldn't suggest the play is excessive, but keep wondering if this is the source of the side milling noise.
I have another actual Bridgeport j-head, gutted, under my bench. A while ago I removed the spindle and spline bushing to compare the play, it's about the same. So, replacing with the Bridgeport part wouldn't be advantageous. But how much tighter would a brand new spline bushing be?

I have had the spindle out a few times, and had the back gear housing off more times, so, I'd assume I've inadvertently tried several different orientations already.

Would there be anything I could tighten to add some restriction to the spindle? So it doesn't have the ability to spin up faster than the pulley? So, it can't "bounce" off the spline bushing?

Could the noise be emanating from else where?

To touch on kens point, running at higher rpms, I sometimes use carbide and often don't use the high speed due to the bad bearings in the pulley and something ringing around the inside of the pulley (pieces of the brake). Maybe once new (I bought them this morning)
and now that I've fixed the brake and shimmed it, I will be able to get higher speeds.

A note, once my 2" facemill engages all 3 teeth, the mill is whisper quiet. But an interupted cut shakes the house down...
Shawn

First 9x42 column mill,
Enterprise 10x28 lathe,
Ko Lee 6x12 surface grinder,
Airco dip/stick 160 welder,
Fully stocked wood shop.

4GSR

Re: Spline/noisy milling
« Reply #7 on: June 07, 2019, 01:42:19 PM »
Every Bridgeport and even clones had this problem.  The only mills I've been around that didn't make this noise were the 9-J Gortons we had many years ago.  But they had another noise problem that was mainly associated with the No. 10 B & S taper in the spindle.
Ken

Carpenter84

Re: Spline/noisy milling
« Reply #8 on: June 07, 2019, 04:10:22 PM »
Alright. That's pretty much the answer I was looking for. Basically to know there's nothing I can do about it and to stop worrying about it. It's really only ever a problem if I'm milling something late at night. It's too noisy. But, once I am in the new shop, I won't care.
...the new shop I haven't had time to work on lately. But, I've been paying our young guy at work to go up there and continue the clean up. He just told me a few moments ago before he left for the weekend that he will be done cleaning it out this evening and will start demoing walls this weekend. Heck, that works for me! I'll have some structural repairs to do before I can start closing it in and calling it my own. If I can sneak up there this weekend I'll post some pictures and an update on the proper thread.
Shawn

First 9x42 column mill,
Enterprise 10x28 lathe,
Ko Lee 6x12 surface grinder,
Airco dip/stick 160 welder,
Fully stocked wood shop.