Bizzar shop incident

[Dave Mcintire]

This didn't amount to much in the end but it was so unusual I thought I'd put it on the forum. I was boring a hole in a piece of hardwood endgrain on a PM 90 lathe using one of those cheap forestner bits that come in 29 piece sets. I never really liked them because they run so hot and need a lot of pressure, but they do cut clean. I had counter bored to 1" with a brad point drill so I thought it would be OK but it was running real hot any way with a lot of smoke. I have a small fan behind the lathe to blow chips away so the smoke didn't bother me. I got about 1 1/2" deep and the chips were coming out in very fine ribbons when they started to burst into flames. Some fell into the chip bin under the lathe ways (which was pretty full) and some fell just under the lathe shaft in another little pile of chips. The fire never got big at all but was in a few different places. I got just a little concerned because I have tons of combustibles in the shop + lacquer, laquer thinner, oil, paint thinner, etc, etc. Fortunately I had an extinguisher handy and started to spray the little fires, they seemed to go out but as soon as I went from one to the next the previous one reignited, this happened about 4 times, the fire extinguisher spray and fan spread the burning chips and they burned down into the pile of chips, so I had to keep putting out new little fires. After a few minutes everything was out and I figured it was a god time to really clean up the lathe and surrounding area. There was no real damage, just a little clean up work, but I never had anything like this before

[Steve Clardy]

Makes a guy a tad frantic at times:eek: :)

[Christopher K. Hartley]

Dave, thanks for sharing. It is always good to have a reminder of things to be cautious of. Glad all is well and you are safe.:)

[Corey Hallagan]

Yikes....I have had a forstener get pretty hot while doing the same thing. Never thought it might burst into flames. Thanks for sharing.

corey

[Boyd Gathwright]

.... Dave, this is a thread you may find of benefit in lite of your experience.



FIRE IN THE SHOP



http://www.sawmillcreek.org/showthread.php?t=27746 (http://www.sawmillcreek.org/showthread.php?t=27746)


;)

.



This didn't amount to much in the end but it was so unusual I thought I'd put it on the forum. I was boring a hole in a piece of hardwood endgrain on a PM 90 lathe using one of those cheap forestner bits that come in 29 piece sets. I never really liked them because they run so hot and need a lot of pressure, but they do cut clean. I had counter bored to 1" with a brad point drill so I thought it would be OK but it was running real hot any way with a lot of smoke. I have a small fan behind the lathe to blow chips away so the smoke didn't bother me. I got about 1 1/2" deep and the chips were coming out in very fine ribbons when they started to burst into flames. Some fell into the chip bin under the lathe ways (which was pretty full) and some fell just under the lathe shaft in another little pile of chips. The fire never got big at all but was in a few different places. I got just a little concerned because I have tons of combustibles in the shop + lacquer, laquer thinner, oil, paint thinner, etc, etc. Fortunately I had an extinguisher handy and started to spray the little fires, they seemed to go out but as soon as I went from one to the next the previous one reignited, this happened about 4 times, the fire extinguisher spray and fan spread the burning chips and they burned down into the pile of chips, so I had to keep putting out new little fires. After a few minutes everything was out and I figured it was a god time to really clean up the lathe and surrounding area. There was no real damage, just a little clean up work, but I never had anything like this before

[Frank Fusco]

I do a lot of end grain boring into hard-hardwoods. My first efforts were with Forstner bits and I experienced almost the same problems you described. Instant heat. Even without the smoke and fire, if you examine the tips of the teeth after just a fraction of an inch of boring you will discover they have blued. On earlier threads others have said they don't experience problems with Forstners doing end grain boring. At about 300 rpm, I do. Maybe much slower would work, I don't know. I use brad point bits now for my end grain and they work fine. Granted, in larger sizes they can be pretty expensive but worth the investment if you are going to use them much. For one-time projects, spade bits do almost as well as brads but are usually slower. I have know of folks who use the old-style, a/k/a Neanderthal, spoon bits with success.

[Ben Rafael]

What speed were you running the lathe at?

[Jeff Fritzson]

Dave,

I am glad everything worked out OK for you. One of the best things I think this should reinforce is to have an extinguisher readily available that works. Please remember to check your fire extinguishers at least once a year (sort of like changing the batteries in your smoke alarms.) I generally check twice a year during daylight savings (swhich is coming up.)

Regards,
Jeff

[Don Fuss]

Dave, thanks for sharing your experience. I was doing the same operation last night and I started to smell a little burning so I took it a little easier. I have a pretty good mound of shavings under my lathe that I am going to go sweep up right now.

[Don Baer]

Dave,

I am glad everything worked out OK for you. One of the best things I think this should reinforce is to have an extinguisher readily available that works. Please remember to check your fire extinguishers at least once a year (sort of like changing the batteries in your smoke alarms.) I generally check twice a year during daylight savings (swhich is coming up.)

Regards,
Jeff

Thats all well and good unless you live in Arizona where we don't change time..:cool:

[Vaughn McMillan]

Thats all well and good unless you live in Arizona where we don't change time..:cool:
Don, I think Arizonans should be required to change their smoke alarm batteries every month, just because. :D

[Richard Madison]

Love my cheapie set of forstners but I haven't done the hard hardwoods, so maybe that's it. End grain boring the softer stuff (box elder, hackberry) works ok, 150 to 250 rpm depending on size, to 2" dia. bit, bore about 3/4" depth, extract the bit and let it cool a bit. Bore another 3/4" depth. Ignition temperature of wood is somewhere in the range of 400 F, but you must be getting it a lot hotter than that to blue the bit. Turn slow, feed just fast enough to get shavings rather than dust, and stop often to clear shavings and cool the bit and the wood.

[Keith Christopher]

I know what you mean I had a post a while back when I using a spiral upcut to make a mortise in some anigre. I usually keep a bucket of water near for cleaning up squeezeouts and such. but is made me look at my layout of the FE's in my shop. I am always concerned about the force of the FE's blowing chips and sawdust around. Glad it wasn't more serious !

[Robert E Lee]

Dave, you need to sharpen those bits and they should not be getting that hot. I blow air from the air hose into the hole while drilling and that helps keep the chips out and the bit cool. Helps a little, before it gets hot enough to smoke I let it cool.
Bob

[Paul Engle]

fostners run best under 300 rpm, if you dont put preasure on em they will heat up and not cut, ( kinda like metal machining, go quick with slow speed let the spent chips carry the heat away, or ( tongue in cheek) put the wood in the freezer for a day or so ......

remember as Red once said" if they cant find you handsome , they should find you handy "
Paul