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Lathe

Problem with my lathe

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Ronen Burstein30/03/2020 19:00:14
4 forum posts
1 photos

Hi There

New to the forum and to working with lath. I recently bought a Waco WM240B Belt drive lathe.

It worked well in a sense that it gave my smooth fine surface. But the other day I change gears for thread cutting, then change it back to the original setting (presumably) and ever since i got very raged surface finish even thug i am using the automatic feed. When it got to the end i disengage the cutting head and manually bring it back to the beginning. During the path back i can see that the cutting head still cutting the metal? (See attached photo). Any idea what wrong?

Thanks

Ronen

img_1349.jpg

Chris Evans 630/03/2020 19:54:03
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1625 forum posts

Have you returned all the levers to their original position ? Seems like you still have the leadscrew engaged or federate positions wrong. You should wind the tool away from the workpiece to return to the start position.

not done it yet30/03/2020 19:58:58
4477 forum posts
16 photos

Typical cutting on returning the cutter to the starting point is poorly adjusted gibs on the carriage. But you problem could also have other causes. A poor cutting edge is among the others.

Andrew Johnston30/03/2020 20:14:22
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5399 forum posts
621 photos

Change of material? Tearing is common with low carbon steels and insert tooling if you don't get speeds and feeds correct. Cutting on the return is common. It can be caused by the work deflecting away from the tool slightly on the cutting pass and then springing back.

Andrew

Grindstone Cowboy30/03/2020 20:25:33
268 forum posts
24 photos

Looks like you're cutting a thread there, so it's understandable that it would cut the untouched sections when you wind back. Does the carriage move slowly or quickly when using the power feed? As others have said, check you have reset everything to how it was before.

Rob

Oldiron30/03/2020 20:49:14
414 forum posts
22 photos

I agree with the others. Are you sure that you have set everything back to as it was?.

Just a tip:- your posts are easier found and likely to get a better response or help people searching for a similar problem if the title was a little more descriptive, ie

"Rough finish after changing settings".

regards

Martin Connelly30/03/2020 22:13:53
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1211 forum posts
146 photos

Back off the tool before returning to do the next cut.

Martin C

DMB30/03/2020 23:04:24
992 forum posts

Hi Ronen,

Did you get a manual? If so, consult it. It may well list all wheel configurations for threads and feeds. Assuming change wheels rather than gearbox, use largest wheel available on leadscrew. You need a huge gear reduction to get a very low leadscrew speed and thus, a fine feed. I'm not au fait with Warco lathes but if all else fails, ask makers for help/advice. Have found owner, Roger Warren a pleasant and helpful  chap to deal with.

John

Edited By DMB on 30/03/2020 23:07:38

Edited By DMB on 30/03/2020 23:08:28

Edited By DMB on 30/03/2020 23:09:06

Bo'sun31/03/2020 08:17:25
78 forum posts

What tooling are you using. HSS or carbide tipped tooling? Positive or negative top rake? I've seen negative top rake cause this before, especially if you have a longish workpiece unsupported by the tailstock. Some refer to it as "springback".

Tony Pratt 131/03/2020 08:32:31
1098 forum posts
3 photos

Thinking logically, something must have changed from when the lathe was cutting a good finish? Material or as previously mentioned are the change wheels correct for a fine feed?

Tony

Bo'sun31/03/2020 09:04:54
78 forum posts

Too much tool overhang maybe?

Hopper31/03/2020 09:18:57
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4379 forum posts
92 photos

The marks on the piece in the photo look maybe like the feed is still in screwcutting mode. Looks like one set of marks about 1mm apart going in the right hand thread direction, then another set coming back in the left hand direction.

Looks like you maybe need to check your lathe owners manual and the settings of all your gearbox levers and change gears or whatever you changed when you went from fine feed to screw cutting. Sometimes you have to jiggle the headstock spindle back and forth as you change the gear levers on the gearbox so they can move to the new position fully.

A picture of the work after one cut without winding the carriage back would give a clearer view of how the tool is cutting. The return marks are somewhat confusing the issue I think.

Edited By Hopper on 31/03/2020 09:20:18

SillyOldDuffer31/03/2020 09:30:02
5605 forum posts
1153 photos
Posted by Hopper on 31/03/2020 09:18:57:

The marks on the piece in the photo look maybe like the feed is still in screwcutting mode. ...

Looks like you maybe need to check your lathe owners manual and the settings of all your gearbox levers and change gears ...

...

+1

Hi Ronan,

As it's a WM240, the most likely cause is the change gears. These are set up in a particular way to do fine cuts and re-arranged in various ways to cut thread pitches. My guess is the gears were put back incorrectly, and are producing a coarse spiral.

Can you post a photo of the change gears? ( Gears and belts under the cover on the left-hand side of the headstock.) If something is wrong, should be possible to see it.

Dave

larry phelan 131/03/2020 09:51:08
649 forum posts
22 photos

Yes I think you are set up for screwcutting, not turning. Can happen, ask me how I know !!

Ronen Burstein31/03/2020 10:01:05
4 forum posts
1 photos

Hi There

Thank you all very very much for your replay. I think the problem must have been because of me putting back the gears wrongly. I am not sure that i can see in the manual the original setting but i will contact Warco for that.

Thanks again for all your replay. I got a lot of tips & trics out of it.

Regards

Ronen

Bo'sun31/03/2020 10:29:38
78 forum posts

Hi Ronen,

The original setting is probably the one for "fine feed". Likely shown in the manual, or on a plate on the front of the machine.

Journeyman31/03/2020 10:39:16
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776 forum posts
131 photos

The manual should have a chart like this

feedchart.jpg

Or indeed there is a chart affixed to the change gear cover that shows where each gear should be. The chart above is for the WM250 but yours will be very similar. Don't forget the 3-way gear change knob on the front which also needs to be set to its slowest range position C.

John

Bo'sun31/03/2020 10:59:27
78 forum posts

If it's any help. my WM240 came set-up with 90T, 90T, 80T, 33T & 25T (+ 2x40T fixed) change gears for fine feed. I didn't know the WM240B came with a 3-way gear change.

SillyOldDuffer31/03/2020 11:09:43
5605 forum posts
1153 photos

+1 to John (Journeyman's Chart)

The fine feed settings are shown at the top, and I've ringed the set-up I'd use in red.

wm240fine.jpg

I think the example gear arrangement pictured on John's picture is what's needed for fine feed. The big 80 toothed gear at bottom 'L' engages with a small 20 'Z3' hidden behind the big 75, 'Z4'. That engages with the visible small 25 'Z1', which turns the big 70 'Z2' behind. The 70 toothed gear engages with the spindle hidden behind the pulley.

All my gears (for a WM280) are stamped with the number of teeth, but the numbers aren't obvious! I've written the numbers on boldly in felt tip to make life easier. (Felt tip needs a grease free surface.)

Dave

 

Edited By SillyOldDuffer on 31/03/2020 11:11:55

Journeyman31/03/2020 12:39:09
avatar
776 forum posts
131 photos
Posted by Bo'sun on 31/03/2020 10:59:27:

If it's any help. my WM240 came set-up with 90T, 90T, 80T, 33T & 25T (+ 2x40T fixed) change gears for fine feed. I didn't know the WM240B came with a 3-way gear change.

Your right, the WM 240B doesn't have the extra lead screw gear change. My bad, sorry.

John

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