Chipmaster developed a knocking noise

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Chipmaster developed a knocking noise

This topic has 10 replies, 8 voices, and was last updated 7 November 2023 at 16:03 by Alan Jackson.

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21 October 2023 at 10:31 #678349
Milly S
Participant
@millys
Hi all glad to be back

my Chipmaster has developed a knocking noise,took back plate off headstock checked shaft/bearings/oil drip tube & anything else I could see all seemed ok

took front gear box cover off checked gears cogs shafts & bearings all seemed ok no play no nasty loose bits of metal

took belts off to check motor all ok

don’t know what to look for next

any help appreciated

cheers

steve
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21 October 2023 at 14:22 #678680
Chris Crew
Participant
@chriscrew66644
Without hearing the noise for ourselves it is very difficult to know what to suggest. Can you locate the knocking to a particular part of the lathe? Does it occur at all speeds when different gears may be engaged? Perhaps one of those old-fashioned listening devices, sort of a door-knob on the end of a metal rod, may help. They used to use them for detecting knocks in car engines, they may still do but I gave up working on anything to do with cars when they became a computer on wheels.
21 October 2023 at 14:57 #678698
SillyOldDuffer
Moderator
@sillyoldduffer
A broken shear pin confused me once because it intermittently slipped on the burr. Everything looked OK!

I’ve used a big screw-driver and lengths of wood as a stethoscope as described by Chris. Helps considerably to zero in on where the clonk is coming from – loudest. Like many old-fashioned ideas, it works, but not particularly well. These days proper doctor style stethoscopes can be had quite cheaply – worth buying one.

Also is there a pattern? Such as only occurring when the gearbox is engaged, or when cutting etc. Try to narrow it down, for example does it clonk when the motor is run with the belt off? Does it clonk when the spindle is turned by hand and everything else is disconnected. Check the shaft keys in case one has worked loose etc.

Some people enjoy fault finding, I hate it!

Dave
21 October 2023 at 15:17 #678700
Clive Brown 1
Participant
@clivebrown1
On 21 October 2023 at 14:57 SillyOldDuffer said

I’ve used a big screw-driver and lengths of wood as a stethoscope as described by Chris. Helps considerably to zero in on where the clonk is coming from – loudest. Like many old-fashioned ideas, it works, but not particularly well. These days proper doctor style stethoscopes can be had quite cheaply – worth buying one.

Complete thread drift but, not long ago, a water board man came along our road with a nicely made wooden pole about 4ft long. He used it to listen for possible leaks in the water main under the pavement. Real hi-tec!
22 October 2023 at 09:48 #679344
Milly S
Participant
@millys
Hi all

tried the big screwdriver & a long metal bar tight on ear it’s hard to detect as it’s intermittent when it goes it sounds like a knock on metal by a light hammer it stops for a while then starts again this happens at any speed also worse in reverse can’t hear it if you crank by hand

thanks

steve
22 October 2023 at 11:15 #679467
DC31k
Participant
@dc31k
On 22 October 2023 at 09:48 Milly S said

can’t hear it if you crank by hand

Is there a way to bypass the variator and turn the spindle under power? That would eliminate it as a possible source of the noise.
22 October 2023 at 21:10 #680071
petro1head
Participant
@petro1head
May be an idea to video the noise
26 October 2023 at 10:22 #682282
Clive Steer
Participant
@clivesteer55943
I have had a cyclic knocking noise on my chipmaster since I first got it some 20 years ago. However the noise is only audible when I’m using the parting off tool. It appears to emanate from the headstock but since the Chipmaster spindle is direct drive it can’t be attributed to gears. I have removed the variation from my machine so my motor drives the headstock through the matrix clutch which could be the cause. Speed control is by a 7kW VFD but only because I had one. This has, for my type of work, been fine with good performance and quiet operation.

I haven’t investigated further as the noise hasn’t got worse over time or affects the function of the machine.

However my machine has had a fairly hard life in the past so it may be the result of some earlier abuse.

CS
26 October 2023 at 19:46 #682648
Milly S
Participant
@millys
Hi Clive thanks for reply I’ve tried just about everything possible to try and resolve problem with lathe

I asked the company I bought it from to take a look at it which they did unfortunately they could not sort problem

it’s a shame as I would like to hold on to this lathe but not if problem can’t be put right so I’m afraid I’ll be returning it

i would just like to thank everyone who has contributed to try & resolve this problem

best regards

Steve
7 November 2023 at 15:59 #688216
Alan Jackson
Participant
@alanjackson47790
Testing if the system works after writing a long description and it disappeared on posting

Alan
7 November 2023 at 16:03 #688217
Alan Jackson
Participant
@alanjackson47790
I have just written a long description of how I tightened the end nut on the spindle fully tight for the knocking noise at the spindle when turning by hand has now stopped. However my long descrition disappeared whe I tried to post it. Good luck Clive This might work for you.

Alan
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