Chips under my lathe on fire

[Keith Outten]

Last night I was turning a pen blank from rosewood. After a couple of minutes I noticed that the chips under my lathe (about 3 hand fulls) on top of the table were on fire. I scooped the pile of chips onto the floor and put the fire out. I can't say that I have ever heard anyone here discuss a fire from turning wood.

Does this seem odd?

[Robert D Evans]

There had to be an ignition source. Wood doesn't spontaneously combust under those conditions.

[Ted Calver]

Interesting. Glad you caught it. I'm with Robert in trying to identify the ignition source. I've had really hot/smoking chips result from drilling end grain on the lathe, much the same as trying to make a fire by friction. Just normal spindle turning shouldn't generate that kind of heat.

[John K Jordan]

Last night I was turning a pen blank from rosewood. After a couple of minutes I noticed that the chips under my lathe (about 3 hand fulls) on top of the table were on fire. I scooped the pile of chips onto the floor and put the fire out. I can't say that I have ever heard anyone here discuss a fire from turning wood.

Does this seem odd?

Seems very odd to me. I've turned a huge variety of species including various rosewoods, some aggressively, drilling and using all kinds of tools. I have never experienced fire or from turning and haven't heard of anyone else reporting it. You can, of course, get enough friction for smoke and to start a fire from two wooden sticks and or a cord or wire on a rotating piece but hard to imagine excessive friction from cutting with a sharp tool.

There was a beginner recently who reported his skew was getting so hot it had burned marks on it but I think we narrowed it down to a problem with sharpening and technique, perhaps too much pressure on the bevel. No reported fire, though.

[Dick Strauss]

We're you using CA glue as a finish?

[Mike Goetzke]

We're you using CA glue as a finish?

Sorry if this is off track but I had a small scare over the Holidays with some CA glue. I was building, of all things, a ukulele kit and needed some CA for the frets. Long story but the bottle was full of CA on the outside so I used a white shop rag (that come in a box) to hold it. Soon I was surprised that my fingers started feeling warm to hot. Then I noticed smoke emitting from it. I took it outside and pulled the rag off so no harm. I immediately Googled it and found indeed CA can have a bad reaction with cotton - so be aware!

[Keith Outten]

No CA glue involved I was just turning the blank. No other ignition source in the area and my lathe is on a metal hydraulic table. I took another look this morning and I now think that the heat may have come from drilling the blanks, it just took awhile to ignite while I mounted the blank to start turning. It's a four inch long blank and even though I backed the drill bit out after every inch of drilling there is still considerable heat once the bit is deep in the blank.

[Stan Calow]

spark from tool contacting spinning metal parts?

[Reed Gray]

I haven't heard of a fire starting because of CA glue. It does give off 'smoke' as it cures, but I think that is off gassing and not some thing that will cause flame. I could be wrong on that one though.

I have generated smoke in the shop from lots of things, including dull blades on the table saw and drilling holes in dense woods. I have never seen any embers though. I did try a few times to see if it could happen. No success though. If you are drilling some thing like pen blanks and your bit is dull, and you are drilling at very high speed, and you are not clearing your chips off the drill bit, then that will generate a lot of smoke. Bit should be cleared often so you don't build up heat, which can cause blanks to split. Not sure of a rule of thumb here, but twice the diameter of the bit and clear. So 1/2 inch diameter bit, clear the chips every inch you go down, whether it needs it or not...

robo hippy

[John K Jordan]

Sorry if this is off track but I had a small scare over the Holidays with some CA glue. I was building, of all things, a ukulele kit and needed some CA for the frets. Long story but the bottle was full of CA on the outside so I used a white shop rag (that come in a box) to hold it. Soon I was surprised that my fingers started feeling warm to hot. Then I noticed smoke emitting from it. I took it outside and pulled the rag off so no harm. I immediately Googled it and found indeed CA can have a bad reaction with cotton - so be aware!

Cotton, paper towel, wood, anything that contains cellulose I think. I've seen the smoke several times.

Once I had a piece of something simultaneously get very hot AND stick to my fingers. Fortunately I had a bottle of water handy or may have gotten a burn. I learned from that! Spilling some on your jeans while seated may not turn out well.

I use tuffs of synthetic fiber (batting for upholstery) held in hemostats to apply CA where it needs to be spread rather than just drops. That tip came a woodturner years ago but can't remember who. I don't have any trouble with CA and paper towel if I use a drop of oil along with the CA as sometimes recommended as a finish for small spindle turnings.

JKJ

[Kyle Iwamoto]

When you drill your blank, does you drill bit smoke? I'll suggest that you get a new sharp drill bit. If you getting it to smoke, the wood in the blank is hot enough to "burn" and turn black. Which is probably not good for whichever glue method you choose to use. Not to mention possible cracking etc.
On a related issue, you drill 4" deep? Why? I typically size my blanks a tad longer than the tube (To keep blowouts on the other end from ruining the blank) and drill through. I found that drilling longer/deeper can cause the drill to wander inside the blank and sometimes wander enough to make the blank dicey to use.

[Scott Winners]

I was the one blackening my skew edge as a n00b. Sharper tool, better technique, less presure, longer working times, no more black steel. Smoother finish on my work too now that I have some experience. No signs of wood ignition at my place.

[Richard Casey]

I have had a scare using TC tipped Forstner bits. I usually make pepper grinders in sets of 6 pairs at a time, so each stage is repetitive. After I had bored the centre hole through them all I noticed an amount of smoke from the shavings under the lathe. I was using a very hard Aussie timber called Burdekin Plum and I guess the amount of really hot shavings compounded to ignite. After that fright I completely vacuum the work area before I start and then again at completion and remove the shavings from the shed.
So it can happen.
Rgds,
Richard.

[Keith Outten]

I expect my experience was similar. Although the brad point drill bit I was using was new I'm sure that the heat generated drilling such a deep hole caused the chips to smoulder and catch fire. I thought at the time that clearing the chips from the hole every inch of drilling would be fine but I know now that I will have to adjust.

[John K Jordan]

I have had a scare using TC tipped Forstner bits. I usually make pepper grinders in sets of 6 pairs at a time, so each stage is repetitive. After I had bored the centre hole through them all I noticed an amount of smoke from the shavings under the lathe. I was using a very hard Aussie timber called Burdekin Plum and I guess the amount of really hot shavings compounded to ignite. After that fright I completely vacuum the work area before I start and then again at completion and remove the shavings from the shed.
So it can happen.
Rgds,
Richard.

Hi Richard! Hope you are well and look forward to seeing you again.

Don't know if you saw this when I posted earlier, but every time I drill deep holes with a Forstner bit I direct a strong, continuous stream of compressed air into the hole behind the bit. This tends to clear the chips as well as cool the bit. (I usually use carbide Forstner's for deep holes - a little rougher cut but that's OK on the inside of a pepper mill.

Love those tropical Aussie timbers you get, in my book the harder the better when it comes to woodturning!

JKJ

[Richard Casey]

Hi Richard! Hope you are well and look forward to seeing you again.

Don't know if you saw this when I posted earlier, but every time I drill deep holes with a Forstner bit I direct a strong, continuous stream of compressed air into the hole behind the bit. This tends to clear the chips as well as cool the bit. (I usually use carbide Forstner's for deep holes - a little rougher cut but that's OK on the inside of a pepper mill.

Love those tropical Aussie timbers you get, in my book the harder the better when it comes to woodturning!

JKJ
Hi John, no I didn't, good idea, but my worry would be where the ejected shavings would end up. I thought I gave you some of this timber, it would have been marked as TPL. It's not our hardest timber, but at 930kg/ cubic metre, if my maths are correct that's 4.8 lbs/ superfoot your lingo, it's getting up there.
Rgds,
Richard.

[Russell Neyman]

The threat of glowing embers falling onto shavings is always a worry, although I doubt the fire can get very far. My own arrangement is to have the lathe standing clear of obstructions on all four sides on a concrete floor. If a fire should start, it's doubtful it can spread beyond the immediate area. Occasionally, I've had a bit of smoke come from under my work, but there has never been an actual flame. I watch those sorts of things very closely.

The elephant in the room is dust collection. If one of those glowing embers gets sucked into the system and lands in your vacuum bin it could easily catch fire. Any Boy Scout will tell you that blowing it with air will only help things burn.

Heat generated during end-boring is problematic. Forstner bits, especially, create a tremendous amount of friction which heats up the moisture in the wood, causing the wood to expand and cause even more friction. My advice is to start with a smaller spade bit and work your way up to the eventual bore size with progressively larger, well-sharpened Forstner bits. Less heat is less stress on the wood.