Warco WM 250V power feed stuck/crash

A good friend had the misfortune to drive the saddle in to the head stock on a Warco lathe. It was a bit of a struggle to "unjam" things but all seemed well until he tried to turn parallel.

On delivery of the lathe we set it up with a precision level. We checked with the level after the mishap and found the bed had twisted!

We eventually got it turning parallel again, difficult because the cabinet was somewhat less stiff than the bed, nothing to pull against. Eventually he had the bed reground to restore the original accuracy..

All this bother for a moments lapse in concentration.

I hope to hear from Warco this coming week.

They need to address the oil leak but more importantly how this happened, I have revisited everything I did and I cannot for the life of me understand how this happened.

As you can see from my photo the teeth are mangled and although not shown in the photo the drive shaft that engages with those teeth is bent resulting in only about 10 cm of free travel left and right before it binds up.

To do that kind of damage to the teeth on the rack and the pinion gear and shaft that engage with it, something must have prevented the carriage from moving along the bed as the power feed tried to keep it moving. Usually this is something like the toolpost hitting the chuck or headstock, thus preventing any further movement. Or possibly the carriage lock was on? Or the halfnuts engaged?

A pic of the lathe overall showing where the carriage and toolpost etc are in relation to the headstock would be helpful in working out what jammed up or crashed into what.

Edited By Hopper on 05/06/2022 08:52:42

I had only just completed 2 manual cuts and so the carriage lock was not engaged nor did the tool post hit the chuck or headstock. I am at a loss what caused it, hopefully Warco can shed some light on it for me.

As the rack will be soft, bent teeth can be straightened with due care by using a shaped brass punch to push them back into position, as long as the damage is not severe. In this case the degree of damage looks to be within recovery and the rack could be salvaged. It is a choice Bombadier may care to try before coughing up for a replacement, particularly as the circumstances which gave rise to the damage are not apparent 

The job is best done with the rack off the machine and held rigidly in a vice using protected jaws. The degree of success can be judged by rolling a correctly matching gear in the rack to test for any tight spots or lumpiness as the two components mesh together

Regards Brian

Edited By Brian Wood on 05/06/2022 13:00:47

Edited By Brian Wood on 05/06/2022 13:01:34

It's full of risk to speculate, but I think the tooth directly below the tubular location dowel in the photo has fractured and can't be recovered - trying to reform it would most likely result (IMO!!) in the top 2/3 breaking off. Several others are in a bad case too. I'd say the rack has to be replaced.

As for cause I'm wondering if a substantial piece of solid debris (which might still be there in the adjacent toothspace?) got into the meshing pinon and trapped between it and the rack.

I still think the leadscrew shearpin wants looking at, because it should've broken well before any such damage was caused. That's what it's for.

To bend the rack teeth like that the saddle gear must have been forced down so all the force was on the gear tip. If the gear tooth was fully engaged you could only shear the teeth. Check that the saddle bolts are tight to the front plate, and the pinion shaft and teeth etc are ok.

When I had my disaster, the gear/shaft was in stock, so obviously a frequent event and a good seller.

In view of the low strength component, I made a new shaft from 16mm Silver Steel, and cut my own gear to Loctite into it. This required a brass spacer to locate the shaft relative to the Apron, and was how i found errors in the chart for HV6 Rotary Table.

It won't happen again, as I ground off the first four teeth of the racxk, (Two were badly bruised anyway! )

The pinion comes out of mesh just before Saddle / Headstock contact, so occasionally needs to be pulled back into mesh.

Howard

The mighty WARCO have agreed to completely replace the lathe.

Although that is great news I now need to take the old one off the bench and put it back on its pallet, take delivery of the new one . load onto bench, clean and oil etc, oh what joy

Great customer service from WARCO though I have to say

That certainly is a good result, It saves Bombadier all the worry and concern about replacing the rack or doing anything to it as I suggested.

The cynic in me wonders if they have found a fault with this model and this is their way of applying good customer relations and hiding the problem rather than issuing a recall.

Brian

Time will tell Brian however I am going to be more positive and hope that is not the case

It's a fair result in that it gives Bombardier a new machine and saves investigation of any other consequential damage.

I'm pretty sure the rack is toast, and I'm not sure how much skilled machine tool fitter resource they have, to be able to send one out to replace it on site - plus of course resolve the bent pinion shaft issues, and replace the shearpin with one that'll function as it should. It'd take a posh top-o'-the-range dealer to do it that way, and that would have to push up new sale prices too.

The red patch on the photo implies to me that the pinion hit the bed so I suspect that something like a circlip or grubscrew holding the gear shaft in the gearbox was missing and it worked its way outwards from the gearbox.

That makes sense, also about 5 teeth damaged to various degrees.

Tony

Edited By Tony Pratt 1 on 06/06/2022 17:45:57

Yes - highly plausible - or maybe an obstruction in a toothgap in the pinion deflected the pinion downward so the rotating tooth crowns scarred the bed whilst the intrusion mashed the rack teeth.

Again - why didn't the shearpin shear? Wish I'd kept mine now - I replaced it with brass but suspected the original might've been silver steel.

Edited By Mick B1 on 06/06/2022 21:47:22

And all this started with a powered cross feed operation?

Easy to get confused! We have two different lathes in discussion here. First was cross feed then picture posted by Bombardier was a different one.

Indeed. I had assumed Bombardier applied the red mark to point out the are of damage. But it seems to have circular marks indicating the pinion impacted the bed when looked at closely. Shaft or gear obviously moved for some reason.

Good result getting a new lathe anyhow !

Well new lathe has been back on the bench for a few days all going great until today when I was doing a power fed facing cut and the whole cross slide jammed up, I had done at least three identical cuts with no issues prior. Any ideas what could have happened.

With me, if something could go wrong it usually does

I take it that you were not exceeding the Cross Slide travel in either direction?

having been careless myself, I can probably say that you have either been unlucky, or like me, careless.

Either way, you need to find out how this happened a second time and find a way of preventing repetition.

Long shot

Is it possible that something inside the Apron is causing the jam up?

howard