Teasing out the swarf!

Today i just had the mother of all bind-ups or "birds nest" on my machine.I took a big 10mm cut into nylon.

It got so tightly wrapped around the chuck that it even got inbetween the spindle flange and spindle. It wasn't your average nuisance.

So i've just sat there for well over an hour trying to get every last bit out of the gap. But there were some stubborn stringy bastards still left inside.

I was at the end of my tether so i considered a last ditch attempt at getting it out. Setting it on fire!

I wouldn't recommend this to anyone without considering your own responsibility first and excercize caution like using any other method that could be dangerous, just to clear the air on that first.

I used a rather small butane torch to get at the swarf underneath the chuck, i let it burn for a few seconds before extinguishing it with a good puff.

And at last the swarf was no more. It sounds rather odd but it worked, as nylon has a relatively low melting point, this minimizes the risk to damaging other metals which have an extremely high melting point.

This has inspired me though to come up with a new project to protect against this event.

Has anyone ever heard of using a large diameter piece of tubular plastic sheet or gasket, and then fixing it to a pair of clasps with a interior rolling clasp. This might be a good way to prevent the swarf doing such damage again.

It would be kind of similar in principle to the bellows people use to protect lead screws and readout units, except this one would be for the head of a lathe.

Michael Walters

Edited By Michael Walters on 15/09/2016 14:34:55

with nylon, if you have a shop vac, you could suck the swarf straight up the nozzle.

Roy

Your burning method is dangerous in two areas - it is a major fire risk and you do not want to be breathing smoke from most plastics. It is a major health risk to breathe plastic smoke.

Plastics can smoulder even with no fire visible, so you could have a shop fire long after you leave the workshop.

Be smart and remove plastic swarf with pliers / razor knife. Don't let birds' nests build up, stop often and clear them. JD

Why not try a large 'o' ring that you can slip over the spindle flange that can be abutted to the back of the flange, or a large wide 'jubilee' clip that you can fasten on to the flange, be careful as obviously you will have the clip screw fastening going round with the spindle... as with previous comment, don't let it build up to such a state in the first place ... my tuppence worth.

George.

Edited By mechman48 on 15/09/2016 14:53:03

Wouldn't it be better to think of a way not to produce the stringy swarf in the first place rather than have to deal with the aftermath? i.e solve the root cause rather than band aid the result? Slower feeds, shallower cuts, chip breakers(if possible to do with nylon), a different plastic perhaps?

Ed.

It is quite interesting reading some of these comments to think that I can almost know instantly that someone will overreact or flinch at the first sign of danger. I mean no disrespect to them personally but i would remind people that this world was not built by people who didn't take risks.

Plastic is plastic by nature funnily enough, so it will always bend before breaking, it is not stiff enough to chip, even on glass filled. The birds nests build up fairly rapidily, even when i accomodated for this by trying a two stage approach it did not work, the same thing happened again, albiet thinner strings than the previous, which could be worse if it gets really dug in the gap.

The problem is the cutting has to happen too close to the chuck, but i can't chuck up 300mm of 2" bar just to get away from the chuck.

An o-ring sounds like a possible route if i can get it to go over the spindle flange. You may not have read that i've already tried cutting away most of it before i couldn't get any closer to the final bits.

The smoke is just blown away by the fan after i've let it burn for a few seconds. I couldn't care less about breathing in a bit frankly.

Michael W

Michael W wrote . I couldn't care less about breathing in a bit frankly.

Its possible that in time you will

Time is one thing i barely have hold of. I could be hit by a meteorite tomorrow. Fact is i'm still standing.

Edited By Michael Walters on 15/09/2016 16:15:11

There's a difference between taking risks and managing them.

Before burning plastic I would at least read the Material Data Safety Sheet before reaching for my lighter.

As an example the MDSS for Nylon 6 says:

General Information: As In Any fire, wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion.

Most people who die in fires are killed by the fumes.

Please be careful - I enjoy your posts and would like to read more!

Dave

You have no control whether you are hit by the meteorite, but you have control about breathing in poisonous fumes. We humans are our own worst enemy at times, god knows how much Granite dust and cement dust I have breathed in over the last 40 years, and I still don't wear any masks even though they are provided. Certainly if I were younger and just starting out in the Masonry trades knowing what I know now, then I would wear them.

I would like to thank for the appreciation and concern displayed, I do also respect that smoke is a killer and some things in small amounts over a long period of time can cause big damage.

When i worked on a powder blasting machine, we used this very fine aluminium oxide powder that would vanish almost as soon as it slipped through your fingers. I decided, for the hell of it, or regulation i would put, to start wearing the mask provided, alot of other machinists didn't when working it. I looked at my mask after a month of use and the filter was almost full of dust, no wonder it was getting sweaty to wear it. The compartment is totally screened off so you don't actually see this dust when using it.

It doesn't seem a problem for five minutes but it is if you're on it for 4 hours a day. I kept the mask as an example to anyone i trained up from that point, company didn't bother enforcing it so, it was all down to me personally to ensure actual compliance in the end. Everyone i trained wore the mask after looking at it.

I do believe a famous greek philosopher once said to entertain an idea is the mark of an educated mind, or look at something from the other side of the fence, as i would call it. I try to abide to that, and i still feel like i mitigated the danger, by removing what could be got at with a razor blade or picker first, thereby avoiding burning swarf unnecessarily and at no time did i feel like i had no control over the little flicker of flame, nor was there anything nearby it could also burn. At last resort, i always keep a full pale of water in the workshop in case the world gets tipped upside down and the shed sets ablaze.

Back to the idea of a guard of sorts, i do like my idea of a fully sealed cover or gasket, but it is complicated to make a big rolling bearing, so the idea needs slimming down, i'm going to add a small guard from metal on some redundant plastic guard holder i took off for rooms sake when using the four jaw (shes a big beasty). So i don't need to modify the machine, and bend over the edges to avoid cutting myself or anything deflecting from it on the machine. It wont take up alot of room so i wont be sacrificing any ability of sorts.

Michael W

My workshop bin seems to be half full of plastic swarf!

Neil

Personally I would have used some side cutters and a pair of long nosed pliers to remove the birds nest. Just a thought as I believe it would be a lot safer.

Martin

I couldn't actually reach it Martin, not without taking the whole thing apart. The gap is about 0.5mm

Michael W

So did it all burn away to nothing or are there odd ends left in there that did not burn?

I let the flames linger for a few minutes, til they either died out, or it was probable at that point they were all gone. They lingered so i decided to put them out, you see, when i turned the chuck, i could hear the tendrils chafing the metal, and after i did that, i couldn't see much left and it runs silently now.

Michael W

So if there was still burning material when you extinguished it then there must still be something there that was burning as there is no fire without fuel.

That could well be, but where should i stop? It isn't causing problems on a noticeable level anymore, save of taking apart the entire assembly, theres little else i can do. The headstock has alot of parts and if you look on youtube for a video of taking a CL430 headstock to pieces it's not easy and probably 2 or 3 day job.

Michael W

Hi Michael,

Referring to Jason's comment above, I've just had a look at the youtube video that you mentioned (not being familiar with your particular lathe) & hope that you haven't torched the front bearing oil seal during your plastic purge. If it is damaged you may well find yourself having to do the headstock strip-down to replace the seal before the bearing gets damaged by lack of lubrication or ingress of swarf etc.

Fingers crossed, Martin.

That could lead back to Andrews vulgar (not convinced that was the right word for the circumstance) comment about natural selection, the nylon might be harmless (unlikely) but the seal probably is not. Some seal material can de-compose into very nasty compounds when they are heated above their normal working temperature.

Mark