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Warco WM280V-F Gearbox

Replacing Gears

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Barry Chamberlain 111/03/2020 20:40:09
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Wondering if anyone has any tips on replacing gears on the Myford WM280V-F

Be nice to get some ideas on how to replace broken gears. Original problem was stiff gear change levers which I now know was to down to badly worn/broken gear teeth. I have the front cover plate off. Any help welcomed.

JasonB11/03/2020 20:42:47
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Myford or Warco?

Dave Halford11/03/2020 20:45:31
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If they are unobtainable as spares and the PA is 20deg you can turn the old teeth off and buy new from HPC then bore to fit. 'Glue' with Loctite 603 or similar.

 

Is it a hybrid from some weird genetic experiment?. if so try channel 70 

Edited By Dave Halford on 11/03/2020 20:52:44

Barry Chamberlain 111/03/2020 22:48:55
18 forum posts
10 photos

Hi all, sorry, I was distracted when posting - my lathe is a WARCO WM280V-F. As stated all help is much appreciated.

Edited By Barry Chamberlain 1 on 11/03/2020 22:49:44

S.D.L.14/03/2020 05:20:20
236 forum posts
37 photos

How about just removing the gears and doing a stepper motor and encoder conversion as per this thread

Electronic leadscrew

STEVE

Cabinet Enforcer14/03/2020 15:42:06
110 forum posts
4 photos
Posted by Barry Chamberlain 1 on 11/03/2020 20:40:09:

Wondering if anyone has any tips on replacing gears on the WM280V-F

Be nice to get some ideas on how to replace broken gears. Original problem was stiff gear change levers which I now know was to down to badly worn/broken gear teeth. I have the front cover plate off. Any help welcomed.

Is there some reason Warco cannot provide spare parts?

Given they are plain gears running in oil they should last practically forever, there will be a reason for the failure and you need to work out what it is before fitting new gears.

Howard Lewis14/03/2020 17:53:13
6113 forum posts
14 photos

If Warco cannot provide spare gears, it maybe that some other importer such as Axminster can.

The gears are likely to be Metric, so will be 1, 1.25 or 1.5 Mod, possibly.

If you can measure the gears, (OD and Tooth count, the Module can be calculated.

Depending on how the gears are driven, keyed or splined to the shaft, it might even be possible to replace the damaged gears with ones from another make / model. But they may need the bore to be modified to fit

Howard

Barry Chamberlain 114/03/2020 23:44:40
18 forum posts
10 photos

Update. Many thanks for the input on the problem. Warco can and do supply spares for the gearbox so I have ordered two which are in stock and a third is on order but with a long delivery time! I will now remove the assembly and review the situation. May well try to modify the third gear with one from HPC as per Dave's suggestion if the wait is too long.

I've experienced stiffness with the gear change selectors since original delivery (it went back to Warco quite soon after it was installed for this very problem) but after a time you tend to live with difficulties.

Poor meshing would appear to be the primary cause. This has led to excess gear wear, resulting in the three broken teeth discovered in the base of the casing. Will update the Forum as things develop. smiley

JasonB15/03/2020 07:19:23
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With no syncromesh the changing of gears will always need a bit of help by rotating the huck the chuck.

So first thing to do is make sure it is in either forwards or reverse, no point in rocking the chuck if you are in neutral as it won't move the other gears. Move the left lever to the desired position while rotating chuck by hand.

Next will be selecting A, B or C while slowly rotating the chuck by hand

Finally select lead screw or feed shaft again while moving chuck noting that if in position C you won't get as much movement of the gear train as when in B. again while moving the chuck

If you opt to change on the fly with the lathe running don't do it with any feeds engaged and pause at the neutral, between C&B or between A&B before moving the lever further to the desired position

Journeyman15/03/2020 09:43:35
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1159 forum posts
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The gearbox is fairly rudimentary, if the gears aren't meshing correctly as far as I can tell the only adjustment is by altering the position of the gear-change knobs on their shafts. The location of the gear-change arm and the U-shaped fork is as far as I can tell simply held in place by the ball bearing detent on the underside of the knob.

wm250gbox.jpg

Inside the gearbox, left is the reverse and right the 3 speed ranges

wm250gblid.jpg

Inside of the lid with actuator and U-shaped forks that sit around the gear.

Problem is you cant see anything to check the alignment once you put the lid back on! The pictures are of theWM250 but the 280 is probably pretty similar.

John

not done it yet15/03/2020 10:16:03
6812 forum posts
20 photos

Wow, permitted to change gears on the fly! That surprises me.

I would not be changing any spur geared box while rotating at any speed. A really poor design to have the gear positions dictated by the control knob, unless it only fits in one position. It would seem that either the knob has moved (or been moved) or the gears have broken while changing on the fly.

They may even have never been in proper engagement from new? A truly cheap design?

The position of the knob appears likely able to be set ‘accurately’ by centring from either side of a neutral position? But a very basic positioning device for the sliding gear cluster. Once again, a design built down to a price?

That is my personal view of this problem. Others may disagree and be content with the cheap design.

JasonB15/03/2020 10:33:49
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Few more gears in the 280box, this is a similar PM1127

Looks like the grub screws in the dividing web may need to be loosened so that the shafts can be slid out to replace the gears.

Journeyman15/03/2020 10:50:07
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Yes, a bit wider with the 3 extra gears on the right to select either the lead screw or feed shaft and of course an extra knob and selector arm.

John

SillyOldDuffer15/03/2020 11:19:07
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8693 forum posts
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Not heard of damaged gears on one of these before, so quite interesting! Could it be a gotcha problem?

As others have said, this class of lathe isn't fitted with a gearbox designed to change in motion. There's no synchromesh as found on a car. Instead, the box is just a very simple sliding arrangement. Robust, but no provision whatever for assisted meshing.

On this type, gears are changed with the power off, usually needing the operator to turn the chuck slowly to and fro by hand to align the teeth whilst gently turning the controls. When a tooth finds a gap the gears engage easily enough, though on mine gear changing is always a bit notchy.

It is possible to change gear with the lathe under power, but how well it works is pure chance. If teeth happen to align when the control is moved, it works. Otherwise there will be more-or-less crunching.

The Manual provided by Warco with my 280VF is quite good, but terse. As far as I can see the Manual doesn't mention the lathe has a crash gearbox, or explain how it's worked by the operator. Neil wrote a helpful book on the mini-lathe - perhaps he should do one covering the next size up; the WM240 to WM290 type are similar.

Just a guess - maybe Barry has an alignment problem.

Whatever the cause, hope it's back on the road asap!

Dave

PS. Reading the Manual reminded me I really must do an oil change. blush

Journeyman15/03/2020 11:29:29
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Posted by SillyOldDuffer on 15/03/2020 11:19:07:

PS. Reading the Manual reminded me I really must do an oil change. blush

If the WM280/290 gearbox is similar to the WM250 the biggest problem with an oil change is getting the oil out as the drain plug is half way up the left hand side behind the change gears. So to empty it completely you either need a sucker or take the front off which is messy. I fitted an extra drain plug on mine behind the aluminium front plate *** LINK *** which is much closer to the bottom of the box.

John

Dave Halford15/03/2020 11:40:39
2050 forum posts
23 photos

it's a 'bit' like a two shaft version of the Centec gearbox except the forks are bronze in a Centec. The forks must be able to swivel freely.

Does the box bind if you change gear with your fingers?

Mike Woods 115/03/2020 12:50:21
40 forum posts
1 photos

Barry,

Started reading this post whilst making breakfast this morning, The inner engineer woke up then the diagnostician started yammering multiple scenarios in my ear, so I was totally distracted. In the meantime I had cut some bread and buttered it. Forgot the toasting part completely!

Is there a chance of posting a picture of the damages gears, it would help the model engineering "hive" mind to assist you. Your comment about poor meshing suggests (in my mind) partial engagement along the length of the gear teeth perhaps?

With the cover removed, do the levers move freely and do the detents operate positively. As mentioned by Dave Halford, do the selector forks swivel freely and the floating gears slide freely on the shafts? As you will be stripping the gearbox to replace gears, it is a good time to check that the shafts and bearings are okay.

Are there any signs of excessive wear on the operating faces of the selector forks, particularly if there is damage to the front of the gear.

Yes it is a nuisance that you cant see what is happening with the cover in place, but you could measure the distance from the edge of the cover to selector fork faces in each of the lever positions, then move the gears manually by the same measurement from a suitable datum.. That may help to identify if there is a problem with the geometry/setup of the selector levers and detent positions, a problem found by quite a few owners of bench top mills with the Hi/Lo gear head down to poorly aligned selectors at manufacture.

The comments about crash boxes in posts above reminds me of a few choice phrases spoken by the chap who guided me though the process of driving older generation vehicles, ranging on order of kindness from:

"Its only a crash gearbox if you get it wrong"

"There's one in there somewhere"

"Alright, grind the b*****s down 'till they fit"

"Arrgh! &@!!^ #@££%&!, you **"%@@"

If coronavirus measures cause us to go into full self isolation, can't imaging anything worse than having your favourite toys out of action. Hope you get it sorted out quickly.

 

Edited to remove the easily spotted blooper, no guarantees that none remain

Edited By Mike Woods 1 on 15/03/2020 12:52:33

JasonB15/03/2020 13:05:58
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Barry was trying to add photos last night, hopefully sorted something out for him so pics will hopefully appear soon.

Howard Lewis15/03/2020 14:54:42
6113 forum posts
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Without seeing the damaged gears, two thoughts

1 ) Trying , frequently, to change ratios while in motion; and crunching every time.

You can double declutch where you can closely control the speed of the prime mover. But lathes do not normally fall into that category!

On a vintage bus or truck, yes, but no on a machine tool.

2 ) Incorrectly adjusted selectors, giving less than full face contact for the teeth.

probably difficult to rest with the selector panel in place.

CUE making up jigs to align the selectors when the gears are fully in mesh.

Do the gears mesh fully in all selector positions? If they don't, that could be a basic design flaw.

Keep us posted on progress!

Howard

S.D.L.15/03/2020 15:33:23
236 forum posts
37 photos

If this works these are Barrys pictures. he sent them to me when he first took the cover off.

657e1f6e-d7ab-419d-b6ba-fa957e33f7e0.jpg

e0ef3f58-a242-49b6-ba62-34162e98d4e6.jpg

Hoping this works

Steve

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