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Warco GH600

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SillyOldDuffer05/06/2020 17:59:01
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6313 forum posts
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Posted by Daniel Bird 1 on 05/06/2020 17:04:29:

One problem i have is with surface finish. So far i haven't managed to eliminate the rough finish shown here (its worse than it looks when you run your nail over it and feels like a fine thread):

I have made the following checks:

  1. Tool height - tried it bang on centre and 0.4mm below, same outcome
  2. Tool overhang - absolute minimum
  3. Speed/feed - tested speeds from 500-1500rpm with no improvement, feed rate 0.044mm
  4. Cut depth - 0.05mm to 0.2mm, same results.

I'm using an insert tool with a fresh edge, it is a TPMR 110304.

Any advice on what to try next or where I'm going wrong would be appreciated.

Incidentally parting off has been a terrible experience so far and i suspect connected to the surface finish issue.

Kind regards

Dan

Checks look reasonable but before assuming the worst what sort of steel is it? I had endless trouble starting out because gremlins filled my scrap-box with nothing but carp metal! Quite a lot of alloys are downright awkward and it can be tricky to get a good finish on ordinary mild-steel.

All bets are off if you don't know what the metal is. If uncertain, order some EN1A or, even better, EN1A Pb. In the event one of those refuse to cut nicely with a sharp insert, then it's definitely time to look at the machine.

Dave

Martin Connelly05/06/2020 18:10:31
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1444 forum posts
166 photos

This is a link to the Little Machine Shop speeds and feeds calculator. Try it for speeds and feeds.

Little Machine Shop

Martin C

Dan_B05/06/2020 18:13:00
18 forum posts
6 photos

The material pictured was brass which seemed to cut OK, lots of fine chips. I also tried a piece of aluminium and got the same results.

The diameter is 10mm. I tested speeds up to 1500RPM and feed up to 0.9mm/rev.

I must say i have very little experience with tip tools so maybe this is some of my problem. The tool is as close to perfect centre.

Is this a less than ideal insert for brass or aluminium?

I will try a HSS tool tonight and also i thought to try a cut with the saddle locked and feed from the top slide - that should eliminate any issues caused by the saddle gib.

I do have some bright mild steel recently bought from macc models so this should also be good for a test.

Thanks for the suggestions so far.

Dan

Howard Lewis05/06/2020 18:24:07
3605 forum posts
2 photos

0.044 mm / rev is a fine feed, and 0.05 mm is shallow depth of cut. Neither of which may be to the liking of a carbide insert. They were intended to remove metal quickly with deep cuts and fine feeds, producing heat which softens the metal locally.

It may be that your set up is not producing enough pressure for the tool to cut consistently. It could be that the tool cuts, and then rubs until the feed builds enough pressure for it to cut again. You would see the swarf coming off intermittently, rather than continuously.

Also, brazed carbide tools are not always finish ground, to produce the correct clearances. that may be contributing to your problem. Replaceable tips are ready to plug and play. But can be ground to slightly different angles to optimise them for particular materials.

May I suggest grinding a HSS tool, ,and if this does not improved the finish, markedly, try stoning a slight radius on the cutting edge of the tool. But don't stop the radius immediately below the cutting edge of the tool, You don't want metal, in what should be the clearance area .

Draw out the tool / metal on a sheet of paper, if it will clarify this.

Learning to grind HSS tools provides a good basis for choosing cutting tools, in the future.

It is possible that you are exerting more pressure in your measurements, than the cutting process is producing.

I don't recognise (NOT expert ) the tip that you are using. (At a guess it would be an 11 mm face with a 0.4 mm tip radius), So, it is possible that the tip is unsuited for the material that you are cutting

Looking at my ARC Euro catalogue they quote CCMT, SCMT, and SCGT inserts for turning.

Someone more knowledgeable may like to comment on your choice of tip.

HTH

Howard

Tony Pratt 105/06/2020 20:05:33
1224 forum posts
5 photos

As Howard suggest, grind up a HSS tool, the geometries for Brass, Ally & steel are going to be different to each other to get the 'best results', you can get one tool which cuts all but it will be a poor compromise at best, the Little Machine Shop website would be a good place to start but there are many more.

Tony

Dan_B05/06/2020 22:06:57
18 forum posts
6 photos

Thank you for your suggestions. I sharpened a hss tool and gave it a try, all was well!

I was given a set of indexable tools ages ago but couldn’t use them on my Myford as the shanks were too big. As soon as I got running with the Warco I changed to these tools so that’s why I have a lack of experience.

The other thing I realised is that I haven’t made the change to metric all that well yet, and the cross-slide vernier shows diameter reduction rather than radius which further screws my brain! Result is superfine cuts.

So is it not possible to take a fine finish cut with an indexable tool?

On to my next problem - oil leak from the spindle. Just looking for opinions really, am I being fussy or is this just too bad. For me the fact that the oil can and does get onto the belts really dictates that I need it fixed. Other than the belts it doesn’t bother me as it drips onto the tray and hasn’t been enough to justify a top up. Thinking negatively though it’s likely to get worse. Haven’t noticed any other leaks but this one is possibly all of the gearbox shafts, quite hard to tell but definitely at least the main spindle.

d6d9fccd-523d-4e57-b5f8-aaa70ea0de26.jpeg

7b79273e-5365-403b-8aef-3249ceab2a4e.jpeg

e58ab21c-6565-47ce-9fa7-d1c21e86fa9f.jpeg

kind regards

Dan

Edited By Daniel Bird 1 on 05/06/2020 22:08:31

Edited By Daniel Bird 1 on 05/06/2020 22:10:31

Martin Connelly05/06/2020 22:51:00
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1444 forum posts
166 photos

Carbide inserts come in all sorts of designations. Some are sharper than others but generally they are not as sharp as HSS. They also perform better when being used in heavy powerful and rigid industrial machines. They can still be used successfully in home workshop machines but they have to be made to work for their living, trying to take a dust layer off something is unlikely to work. The best way to learn what you can do with inserts is to start off with recommended speeds (RPM) and feeds (advance per rev) from a table or calculator and adjust them to suit your machine as you get some experience. There are inserts for aluminium that are sharper than most other inserts and are also polished that get good reviews from home users. You can't treat carbide like HSS.

Martin C

Triumphboy06/06/2020 19:13:09
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21 forum posts
4 photos
Posted by Daniel Bird 1 on 05/06/2020 22:06:57:

On to my next problem - oil leak from the spindle. Just looking for opinions really, am I being fussy or is this just too bad. For me the fact that the oil can and does get onto the belts really dictates that I need it fixed. Other than the belts it doesn’t bother me as it drips onto the tray and hasn’t been enough to justify a top up. Thinking negatively though it’s likely to get worse. Haven’t noticed any other leaks but this one is possibly all of the gearbox shafts, quite hard to tell but definitely at least the main spindle.

kind regards

Dan

Hello Dan

I am dealing with an oil leak here too. Along with one from the saddle spindle which I have machined another oil seal just today as it happens. See my other post in this article about an oil leak from the front of the machine. It's a similar way of dealing with it.

The one you are referring to is a bit difficult to solve because, at the moment, I can see no way to stop it with any degree of professionalism, so to speak. At this time, I have got a series of O rings filling in the gap behind the gear wheel. 3 of them to be exact. I'm hoping that will work but it's a shonky fix to be honest.

Still trying to think of a way to do a better job of it.

TBoy

Dan_B07/06/2020 21:41:20
18 forum posts
6 photos

Hi TBoy,

I read your post about the saddle fix. Luckily mine doesn't leak here yet but i will refer back to your fix if it does. The spindle is definitely the number 1 oil leak issue.

Have you dismantled your spindle and tried a replacement seal? I assumed it would be a lip seal fitted behind the cover but don't fancy taking it apart to look. Have you approached Warco about it?

Dan

Dan_B08/06/2020 14:30:41
18 forum posts
6 photos

I might have been a bit quick in deciding that the poor surface finish was down to the tools. I have been working on some known EN1A mild steel and had the same problem. High/low spindle and slow/fast feeds makes little difference I'm still left with a visible groove that appears like a fine thread. I have used a indexable tool and a fresh ground HSS tool with the same result.

I also tried with the saddle locked and used the top slide feed, finish was OK like this. So i took a gear out of the drive train and manually moved the saddle for a cut, again the finish was ok.

So now i wonder if the issue is coming from the apron some how. I can feel a very regular 'bump' if i hold the saddle handle while feed is enabled, i would say it follows the revs of the lead screw.

To satisfy my curiosity i think i will start by removing the apron tonight and check if something is binding.

I made a check on the lead screw in its fitted state to be sure it is straight, max deviation was <0.2mm which i would have thought is good.

Any tips on removing the apron?

cheers

SillyOldDuffer08/06/2020 15:22:39
Moderator
6313 forum posts
1382 photos

Posted by Daniel Bird 1 on 08/06/2020 14:30:41:

...

So now i wonder if the issue is coming from the apron some how. I can feel a very regular 'bump' if i hold the saddle handle while feed is enabled, i would say it follows the revs of the lead screw.

To satisfy my curiosity i think i will start by removing the apron tonight and check if something is binding.

I made a check on the lead screw in its fitted state to be sure it is straight, max deviation was <0.2mm which i would have thought is good.

Any tips on removing the apron?

cheers

 

Agree something is wrong now cutting Brass and EN1A both misbehaved and that regular bumping isn't right.

Not familiar with the GH600, but I think it has a feed-shaft. Are the lead-screw and feed-shaft both turning at the same time? They shouldn't be. Or is the saddle being moved by the lead-screw instead of the feed-shaft?

On dual-shaft lathes the lead-screw is for cutting threads and the grooved feed-shaft underneath separately provides power to move the saddle along the rack or to traverse the cross-slide for power cuts. With this arrangement the half-nuts should be disengaged completely other than when threading, so the lead-screw shouldn't be influencing the cut unless it's accidentally connecting.

Have a good look at the lead-screw, feed-shaft, half-nuts and gear settings. The selectors on my WM280 gearbox are slightly 'off' and I have to make sure the two shafts engage and disengage properly. Usually better to change gear by rocking the chuck to and fro manually rather than under power. (Unless the GH600 is special definitely don't change gear at high-speed - the gearbox is probably very basic, no synchromesh, and the cogs won't like it.)

Can you take some photos of the control settings? Another GH600 owner might spot a misplaced lever or whatever. Be nice if it's summat simple.

On my lathe I have to be careful not to drive the saddle or cross-slide when they're locked, or to drop the half-nuts on to the lead-screw whilst the saddle is being driven by the feed-shaft, etc. Not difficult to make mistakes.

Other possibilities: slipping clutch (if it has one), or slipping drive due to a broken sheer pin. If the tool-post is crashed under power into the chuck, a pin should break to disconnect the drive. They often break such that there's enough friction to turn the shaft unreliably, maybe creating the thread effect. Physically holding the saddle back as it moves under power should be enough to slip the broken pin and stop the affected shaft rotating as proof. Don't fall into the machine or apply excessive force!

Dave

 

 

 

Edited By SillyOldDuffer on 08/06/2020 15:24:45

Jed Martens08/06/2020 15:39:26
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84 forum posts
54 photos

Apologies, I may have the terminology wrong here, but I'll do my best The GH600 has a single powered shaft / leadscrew. For threading, the half-nut engages with the thread on the leadscrew to drive the carriage. For power-feed, there is a long slot milled in the lead-screw, which a key engages with.

The apron is easy to remove - I had to tackle that when fixing the saddle lock. From memory there are 4 bolts that go through the the top of the apron - remove those (and have some support underneath the apron so it doesn't drop on the floor) and you're done.

edit : this photo shows two of the blots. The top right of the three bolts (removed in this photo) is for the saddle lock. The other two secure the apron. There are a matching pair on the other end.

20200208_163534.jpg

 

Jed

Edited By Jed Martens on 08/06/2020 15:47:21

Dan_B08/06/2020 15:56:22
18 forum posts
6 photos

Hi Jed,

I studied your photos to get the best idea i could on how the drive works in the apron, it has been useful.

I have tried running it in different ratios to see if it was maybe the gearbox causing the issue but it seems to be the same no matter what.

I have noticed once before that if i run the spindle at a fast speed at the same time as the feed was set high (was drilling a small hole after a threading operation) then i noticed the whole machine vibrate. I assumed at the time that it just wasn't meant to be run like this and made a mental note to slow the feed down after threading even if i don't need to run the saddle under power.

It will be interesting when the apron is off to see if there is a tight spot or a shaft that isn't quite concentric.

Dan

Triumphboy10/06/2020 18:04:11
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21 forum posts
4 photos
Posted by Daniel Bird 1 on 07/06/2020 21:41:20:

Hi TBoy,

I read your post about the saddle fix. Luckily mine doesn't leak here yet but i will refer back to your fix if it does. The spindle is definitely the number 1 oil leak issue.

Have you dismantled your spindle and tried a replacement seal? I assumed it would be a lip seal fitted behind the cover but don't fancy taking it apart to look. Have you approached Warco about it?

Dan

Hello Dan

There appears to no seals anywhere on the gearbox or the saddle so it's been leaking from at least tree places so far. The shafts would appear to be the only thing going through the casing. No lip seals!

I've just machined the part on the saddle block and fitted a seal last week. The part machined was the silver cast iron round piece behind the handle mounted on with 3 screws. I clocked the hole before cutting the seal and found it was out by about 12 thou so used shims in the chuck to keep it concentric.

The one you are referring to might be a really tricky fix. It's a bit annoying in a way because it would cost pennies to make a proper seal during manufacture and make the machine a better quality product.

If your feedshaft direction changer leaks behind the front panel ( The top silver knob) I made a document about doing the fix. I can email it to you if you want to look at it. I've no doubt it will leak from there too at some point. A small amount of oil leaking wouldn't be a problem but in my case, it was excessive so I had to do something about it. I wrote about it earlier on in this thread.

Dan_B10/06/2020 19:07:02
18 forum posts
6 photos

Hi TBoy,

I would like to read about the fix you have completed on the feed shaft direction please. I haven't noticed a leak from this point but i guess it stays hidden behind the panel?

How much oil do you fill with? I didn't see any mention in the manual of what the correct level is. The reason i mention is that my apron was only showing maybe 1/4 up the sight glass but when removed it seems to have been well splashed about.

I wonder if we are overfilling the main gearbox and adding to the issue. I filled mine to around the 2/3rds mark. I can notice a significant drag at high spindle speeds with cold oil. The oil obviously splashes well because the level drops right down when running.

My other investigations are ongoing and i will report back when complete. So far though nothing is bent or damaged but maybe room for assembly and line up improvements. Slow progress i'm afraid with limited workshop time.

Dan

Dan_B11/06/2020 12:55:40
18 forum posts
6 photos

Quick update on my investigation so far.

I removed the saddle and apron to check for any bent, damaged or just badly fitted parts -all appeared OK.

After giving all the parts a clean i have then started to rebuild and check the fit of parts along the way.

The first issue was leadscrew alignment - it was 0.5mm lower at the tailstock and 0.5mm further out from the bed. With the saddle fitted i found that the height of the screw at the tailstock was correct but the spacing out from the bed was not.

With the saddle at the headstock the screw is very hard to turn and heavily in contact with the guide holes in the saddle. So to rectify this the leadscrew gearbox must be lowered.

So i have dismantled to remove the gearbox and found that its adjustment was restricted to nothing because of one corner clashing with a radius on the bed casting - infact the screws would only just align and were really under pressure to insert. The next stage is to radius the offending edge and hopefully i will be able to lower by the required 0.5mm and stop the leadscrew jamming with the saddle.

I believe because of this miss-alignment the small concentricity errors of the leadscrew have been raising the saddle slightly with each revolution and given the surface finish effect that i have suffered. The saddle is not completely restrained on the front way and largely relies on tool pressure to keep it down on the vee.

One other small point, the key on the feed drive screw was sticking out slightly on the end that would be pulling against the saddle during motion, i think this gave the 'bump' that i noticed as it knocked against a gap in the casting.

When i'm done i will post photos, i'm sure that will explain all.

Oh and TBoy, you are correct it is leaking more from the leadscrew direction control than anywhere else.

And on the point of oil leaks - on several places i have found that small tapped holes are drilled through - remove the screw and oil pisses out! Annoying, i might try and fit some short grub screws to plug these up and save future mess.

Annoying that this needs to be done but good to strip clean and learn the machine. I will feel happy too if it fixes my issue. The only part i haven't opened yet is the main gearbox.

I hope i haven't hyjacked the original thread here too much but its all good info on the GH600. If i get this surface finish sorted then i will be really happy with the machine - its nice to work on and a really good size, very neat.

Dan

Triumphboy11/06/2020 15:10:39
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21 forum posts
4 photos

Hello Dan

I have sent you a copy of the document.

So far as I know, the oil level should be about half way up the sight glass. Overfilling it slightly shouldn't make any difference in this gearbox, in my opinion.

I did drill a 2mm hole in the filler plug (underneath the little rubber mat) to let out any pressure as the oil heats up during use and needed to see if it caused a mess but it appears to be ok after a couple of hours use.

Cheers

TBoy

Diy Addict15/06/2020 13:17:23
8 forum posts

I've been following this thread with interest for a while, as I'm on the point of buying one of these lathes. But all of these reports of oil leaks are dampening my fervour!

I wonder if this is true of all GH600s, or have you guys been particularly unlucky? Judging by your investigations, it looks like there's a design fault somewhere.

Anyway, please keep posting. All the best.

Jed Martens16/06/2020 08:22:40
avatar
84 forum posts
54 photos

Hi guys, what oil are you using in the gearboxes?

Prompted by Triumphboy, I've taken the left-hand panel off to have a closer look for leaks. Since I'm new to this, and the machine is often covered in chips and cutting oil, it's possible that I've missed some. There is some evidence that a bit of oil has collected at the front left of the chip tray, but it isn't obvious where it might have come from. I think I'll top everything up and run the machine for a bit to see what happens.

Clearly I don't have a leak issue like Triumphboy though, I think that would have jumped out.

Diy Addict, by the nature of forums, all you're going to find in this thread is people discussing issues. It certainly doesn't represent the hundreds of hours I've spent making stuff with this machine. I really enjoy using it, and I'm glad I bought it.

Edited By Jed Martens on 16/06/2020 08:22:50

Dan_B16/06/2020 09:07:22
18 forum posts
6 photos

Warco sent me some of their oil when i got the machine so that is what i have used. No idea what grade it is as there are no details on the tin.

I do really like my GH600 and consider the oil leak a minor issue. I am going to tackle it as Tboy has written a simple guide and offered to help me out with the fix that he has already developed so it makes sense to me to do it.

I think most machine tools with oil filled gearboxes leak to some degree and i don't expect it to be perfect.

I haven't done all that much work on my GH600 yet but so far i'm happy - once i get over a couple of small issues i reckon its going to be a really good asset in my workshop.

Dan

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