Gear Train noise?

Good morning,

I realise there's not much I can do about it mechanically (unless anyone has any sensible suggestions), because that's the way it is, but I want to cut down the annoying gear train noise on my Warco WM250 lathe.

I'm considering lining the gear train cover with thin, oil resistant insulation of some sort. Has anyone tried this? What did you use? Any pitfalls?

Three things that make a lot of difference.

1 Set the right backlash between gears buy cutting strips of copy paper and squashing between gears as you tighten studs and banjo.

2 make sure you have the washers between banjo and gear pairs the right way round the thick washer should go against the smaller gear, thing washer against larger

3 The banjo can move left-right slightly on the pivot adjust that for quiet running

Edited By JasonB on 14/10/2020 11:32:52

Have you tried any lapping agent on the running gears, sometimes with correctly meshed gears using a lapping agent for a few hours running will quieten things down a bit.

You do of course have to thoroughly clean off any residue after the running period, unless you use the type of compound that stops lapping after a period of use, the name escapes me at the moment but is/was available in green and yellow and a number of grades.

Emgee

Thanks Jason,

I wondered about the different washer thicknesses. Warco recommended loosening the drive belt a bit. It seems to help, but I'm not sure about long term belt life. I'm sure most of the problem is that, it's all a bit sloppy.

Thanks Emgee,

Might try that as a last resort. Fine valve grinding paste may work.

Try setting the gears with paper first and if that doesnt work, try it again. some of those chinese gears are not cut concentrically.

The last thing i would do is use lapping paste or anything on the gears. maybe just a little fresh grease, but it shouldnt need it.

We di have a similar lathe to yours in the next workshop to where i worked and the gears were set badly. The supervisor knew everything so we never offered to help. It was loud.

I have a WM250 & have made a banjo stop adjuster to set the gear train whereas I can take the gear train in & out of engagement. I got the idea from Journeymans workshop where he has a write up on fabricating the banjo stop adjustment, works a real treat.I only use the self act on long turning jobs so gear is mainly out of mesh,only noise I have is belt drive.See below, in it, at the end is a clip of my machine running with gears in/out of engagemant worth doing.

**LINK**

George.

Well worth doing to remove the gear train when not using self feed but it makes no difference to the gear noise when engaged, like George for a lot of the time I don't use the self feed and run my Bantam with the gearbox train disconnected.

Despite old Al's comments my gears ran much quieter after the lapping process using TIMESAVER from GA Watt.

Emgee

I've always set mine on the WM250V the way JasonB suggests, with a squirt of SAE20 into each of the axle oiling points and a dribble onto the engaged gears.

It's nowhere near as quiet as mechman's disengaged condition, but nor is it as chatty as his seems to be when engaged. Even if you ignore the chunking of the flycutter, this video seems to me to rather overstate the noise.

**LINK**

It's never occurred to me to try to suppress it, and the neighbours have never commented...

The gear train disengagement mod as mentioned above (Thank you George) will certainly help but in normal running the most important thing is to set the gear clearances using a sheet of paper between the gears. I find that using plenty of grease also removes some of the clatter!

John

Edited By Journeyman on 14/10/2020 13:44:21

Going back to the gear adjustment; I set the backlash gap as per Old Al said, using paper & set gap on each set of gears working up from the bottom... the paper IIRC was .003" folded giving .006" gap, some may say .004" is preferable. I used motor cycle chain lubricant spray on the gear teeth, slightly thicker than SAE32 but not as thick as transmission oil.

George.

My thinking would be to "Let sleeping dogs lie"

Leave well enough alone.

I’m amazed that these modern machines don’t have a neutral position, that can be selected, between forward and backward on the tumbler gears when the gear train is not required. Less wear, for a start. My ‘over-50-years-old‘ lathe has that facility! Doesn’t reduce the extra noise, when the gear train is in use, but it is possibly less than that modern machine.

Changing the material of one or more gears might well improve the situation. Mine uses Tufnol tumbler gears which probably help. A Delrin (or even PLA ) gear in the train would also likely reduce the noise.

The gear cover could also benefit from a sound deadening covering on the outside as well as on the inner surface.

I found mine got noticeably quieter after I made new, round, banjo studs with more than three working threads. These were turned from the shank of an old aircraft bolt, so they're much better quality than the originals.

I tend to leave the geartrain disengaged unless doing a job that justifies power feeds.

Lining the cover with Dynamat or similar sound deadening material helps. Scraps of self-adhesive lead flashing would be suitable if you have some..

My 280 does have a neutral that disengages drive to the front gear box which is where Fwd/Rev is selected. Same with 250 machines

As I use my feeds (X feed machine) a lot it would not be worth me using the disengage method shown as at least 90% of the time I'm using it and only really knock it into neutral when I've a batch of drilling to do.

The other thing that can start to make a bit more noise this time of year is a cold belt, soon goes away with a bit of use warming it up.

Edited By JasonB on 14/10/2020 14:37:16

In my work days bear centres were +0.002/0.004" (0.05/0.10mm). If making gears you could always include a non metal gear into the train.

Thanks for all the suggestions.

It seems to be a bit of "swings & roundabouts". While the gear train is now quieter, it has highlighted the effect of engaging the auto feed (a little more gear noise). I presume it's not coming from the gearbox, as this rotates relatively slowly.

Full agreement with using paper in the mesh to set the backlash on changewheels, but I would only use one sheet, to give 0.003"

Gears running with no, or too little backllash will be noisy, and wear.

Too much backlash will be noisy because of the excessive backlash, and the fact that for a variety of reasons, the rotational speed (angular velocity) will not be constant.

Applying a really heavy grease (ideally one formulated for gear lubrication ) will quieten things.

For gears within the head, you are stuck with whatever the gears sizes and gear centres provide. Again, a really sticky grease will reduce noise, and wear.

HTH

Howard

On the WM250V the leadscrew powers the feeds as well as screwcutting. There's a worm in the apron, driven by a leadscrew keyway, that passes the drive to the apron gearbox, which is basically only able to apply it to crossslide or saddle, depending on the feed lever setting.

So I've always assumed the slight extra noise comes from the apron gearbox. That wouldn't be under load in screwcutting.

Thanks Howard,

All of that seems to do the trick. Especially applying an "anti-fling" grease. Just got to live with the additional noise when he auto feed is engaged I guess. Maybe it will "bed-in" a bit over time? I had considered a heavier oil than the Mobilgear 627 specified, which I believe is around the 30W mark.

All good stuff on reducing the gear noise at source.

When you have done all you can to reduce the noise you can sound insulate the cover to some extent. Thermal insulation products are not really effective - to deaden sound you need something heavy!

There are heavy sound deadening mats for reducing engine noise in cars and, as suggested above by Nicholas, you can used lead sheet. The thicker the better, wrapped or moulded to fit inside or outside the cover and with as few holes or gaps as possible.

Rod