squeak, squeal and chatter

Am i right in thinking these are general the same thing first, squeak/squeal is chattering? or are they different,

Im getting a squealing squeaky noice sometimes (tends to be when lightly cutting) while trying to cut a grove with a 3.5mm tip grove/parting tool. Ive centralised the tool. kept it sharp.

I dont want to cut too quickly/heavy as im taking my time and also dont want to a jam and damage my workpiece or tool.

is there something im missing to not doing right, or is it ok while cutting slowly?

Am i right in thinking it will squeak because its sliding against the surface of the workpiece with not enough preasure or should i be using cutting fluid to stop this, will the squeal cause any problems (apart for annoying anyone close?)

cheers

What are you cutting, what diameter and at what speed?

im cutting an ofcut of steel, which is 18mm down to about 5mm.

speed....slowest (which isnt that slow) on my exe 3.5 super. i know thats not much help but i dont reall know the RPM. i have a 50mm pully of my motor turing at a guess 150mm. you could probably guess or guage it better from my pic's.

I guess thats one thing i should really know and work out. motor RPM and ratio's of pulleys.

thanks for your reply.

Edited By Lloyd Bowers on 25/02/2013 10:05:57

Edited By Lloyd Bowers on 25/02/2013 10:06:17

I'd say its a high frequency chatter that sounds like a squeel, 3.5mm wide tip is asking quite a lot of that machine can you not use something narrower and take two bites or keep the load on teh cutter and feed constant

J

Edited By JasonB on 25/02/2013 10:20:11

Same result but different causes. Chatter is a low frequency effect caused by the tool/workpiece/machine not being stiff enough and causing vibration. Chatter normally leaves an regular pattern of marks on the work. Squealing is a higher frequency effect normally caused by the tool intermittently rubbing and cutting rather than cutting cleanly.

I would say that your squealing is almost certainly caused by too low a feedrate. My standard parting tool is 3mm wide and I use an absolute minimum feedate of 4 thou/rev. One of the 'secrets' to successful parting or grooving is to keep the feedrate up; no half measures.

Regards,

Andrew

Edited By Andrew Johnston on 25/02/2013 10:15:07

ok cheers, i guess feeding too fast and it jams, so get a nice inbetween? just enough to stop the squeeling?

will it cause any damage squeeling?

Ive tried a 1/8th parting tool (blade and holder) which did the same but again i am taking it easy, so maybe feed a bit quicker. - i notice that sometimes the 1/8th did start to wobble left/right and causing a slanted cut, could that also be too lean on feed speed?

A great deal has already been said on this subject

Do a ME search for "parting" and "parting off"

Edited By Ady1 on 25/02/2013 10:57:10

Lloyd,

Have always parted off by hand feeding, you get a feel for the cut throught he handwheel.

Squealing usually occurs when the workpiece is spinning too fast - chatter when parting will usually wake the neighbours and look like a ploughed field.....

Keep the revs down, lots of lube (WD40 works well) and try hand feeding.

Trevor

The pulley diameters you quote will give about 1500 rpm. OK for turning 18 mm but I would want to reduce the speed to about 1/4 of that for parting, especially on a small lathe. Yes a thinner blade should help - half the width = half the cutting force.

Russell.

ok, thank you all, ill have to look at larger pulleys, or a back pulley system to lower the rpm. I only have hand feed, will try a few things and wd40..

thanks

Russell: I'm not sure how you arrive at 1500rpm? If I read the OP's post correctly he has a 50mm pulley on the motor driving a 150mm pulley, so a reduction ratio of 3. For a 2 pole motor running at nearly 3000rpm (in the UK) that gives 1000rpm at the spindle, for a 4 pole motor running at 1500rpm that gives 500rpm at the spindle.

Regards,

Andrew

Addendum: looking at the OP's pictures I'd guess the reduction ratio is a bit more than 3 to 1.

Sorry, finger trouble again. I meant 500 rpm of course.

Russell.

Hello Lloyd,

Are we all missing something obvious? If tailstock support is in use on a hard centre, could the squeal be coming from that? It would vary with load and maybe more when lightly loaded.

Just a thought

Brian

well that was better, having some confidence and using wd40 it was loads better.

thanks all. again!