Any thoughts on why this happened?

Emibub

PFG, Picture Framing God
Joined
Nov 2, 2001
Posts
9,246
Location
Centennial, CO, USA
I had a scarey episode with my saw last night. First of all I couldn't find my brush so I took a rag and was collecting some of the metal shards away from my fence. The saw was on and I literally got so close to the blade that it made contact with the rag which was right up against my hand. :eek: That wasn't my question I just figured I'd mention it to publicly remind myself that I am operating a very dangerous piece of equipment.

Anyway, I was cutting a metal frame last night and as the blade hit the frame I am not sure what happened. The blade hit the moulding just right and it actually locked the blade into the metal and stopped the blade from rotating. I turned the saw off and lifted the guard and there was this twisted piece of metal partially wrapped around the blade. It was hard to disengage the blade and I assumed it would be ruined or at least have a broken tooth or two. I got it apart and checked the blade and there appeared to be no damage. The piece of frame was severely bent and twisted. I cut away the damage and finished cutting the frame but now it has me spooked. It was regular 1500 profile OEM Designer metal, I am using a combo 100 tooth Ultramitre blade that probably on the near side of needing sharpening.


I have to cut down 6 metal frames of the same nature today and am just a teeny bit hesitant to do so. Any ideas on what made this happen?
 
You might try going through the molding more
slowly. It may be possible that when the teeth
encounter the thinner part of the profile that
they are dropping fast enough to lock on the
uncut material. Just a guess.

Hugh
 
Kathy,
It may have been a piece of cut-off from a previous frame that was lodged between the blade and the motor housing that chose that particular instant to become dislodged and interfere with the rotation of the blade. I had it happen with a wood moulding and though it didn't stop the rotation it did make a helluva noise and knocked the blade out of line momentarily.

Please don't ever use rags around rotational power equipment ever again. I would invite you to meet Daryl Brown as a horrible example of what not to do around woodworking tools. Lost a finger trying to force some warped stock through a table saw. Three weeks later was using a power jointer plane when a piece of his bandage got caught. He was fortunate to have any hand left and not bleed to death.

If you are unsure about safety procedures, talk to a supplier of industrial woodworking tools, or enroll in a continuing education course at a local vo-tec school.
 
Clamp well, Then slow and easy.

Sometimes the cheaper moulding will twist and then catch a tooth.

Mitch
 
I know I know Wally. I felt like the biggest idiot when the rag brushed up against the blade, I mean I felt it. It is just an example of getting too comfortable and not paying attention. It sure got my attention though.

I do go through metal slowly. Maybe I wasn't slow enough on this one. Maybe a tooth hit it just right and it was a coincidence. I am going to be very nervous cutting the ones this afternoon. I have no choice, they gotta be done. As a rule I don't cut much metal but I have to to make money on the OEM ones.
 
.......and I don't have a clamp. I hold it with my hand for some reason the clamps have beene disengaged. I've used it for 3 years and haven't up to this point had any problems like this, or bad cuts. Maybe I should look at getting the clamps working again.
 
Couple of questions Kathy,

#1: what was the moulding number exactly, was it Designer? OEMS are numbered 915 and 905.

#2: Do you cut the metal with the rabbit facing the fence or away from the fence?
 
It was a 915 Jerry. My saw is designed to cut with the rabbit facing towards the blade or away from the fence.
 
about a year ago a customer brought in chops to be cut down of a shape I was not familiar with (not a NB, Designer, Clark).

Anyhow, when the clamp went down something happened and the moulding twisted under. BANG :eek: :eek: :eek: the 2 blades grabed the moulding in a bad way. about 20% of the teeth ripped of the blade from each side. It was a brand new set too. The saw is a CTD pheumatic auto cycle so it made a complete cycle. And yes the saw had my attention.
 
Kathy:

I've had similar problems two or three times in the past, when I was using a single miter saw. The OEM profiles are much thinner and more flexible (mushy), so they will deflect & get caught up by the blade more easily.

If your blade has less than 100 carbide teeth, or if it's time to resharpen, the danger of it happening would be increased.

Use a sharp blade with plenty of teeth, hold securely, and go slowly. And make sure your saw has all of its safety devices functioning properly, because accidents can happen -- as you now know.

If I were you I'd consider adding hold-down clamps. If you have an older Phaedra SawHelper like mine, I recommend the retro-fit clamp kit. It works great on my saw.
 
Am I the only one who would never, ever saw an unclamped metal?

Even with the clamps, I've had small cut-off pieces zing off into space - usually away from me, at least.

Having only lost about 25% of a middle finger, I feel like a lucky guy.
 
Kathy, I can think of only two things that could made your saw behave the way it did, one very likely and the other less likely. I''m pretty the problem was poor support of either the molding leg or the cut off. The molding on either side of the blade has to be solidly supported when the blade hits it. The other, less likely possibility is lack of lubrication. If you don't have a misting system, a wax stick is the best answer. I also don't like combo blades but that's for another discussion. BTW, I don't like to use chop saws and have never felt very comfortable around them (we have three in the shop but they are mostly used on location for installation). In a well equiped shop, there are several better alternatives. Keep an eye out for a used Frame Square Rabbet saw and you'll never worry about cutting either metal or wood again.

I didn't understand. Was the saw simply plugged in when your hand came close (I suppose some would call this situation "on") or was it actually running. If running, you were lucky. If just plugged in, there wasn't much to be concerned about. Off is off unless there is someone around who might hit the switch. I'd have no hesitation changing the blades of a saw still plugged in and I'm an old table saw hand with a full compliment of fingers.
 
Am I the only one?
faintthud.gif

I decided along time ago that I would only deal with metals as chops. I don't get enough requests for metal frames to even consider cutting them myself. Years ago, around 1980, I did cut some, but decided it wasn't worth the added risk/worry.
Neilson & LJ do a nice job of chopping the frames properly. I realize that those of you that do OEM work have a different situation. How's your Worker's Comp Insurance for doing that kind of work?
kaffeetrinker_2.gif
 
Kathy,
I’m glad you still have your fingers to type with! It must have been very frightening. (It would have scared the daylights out of me!)
This would probably be a good topic to start talking about shop safety. I have a rule: no loose anything around working machinery, clothing, jewelry or hair and shirts must be tucked in. Well I don’t have to worry about the hair part anymore.

I heard a loud THUMP in high school shop one day and spun around to see the guy next to me with his head smashed into the side of a drill press. It seems he “forgot” to tie his hair back even after being told to do it everyday. It took the paramedics a couple of hours to cut his hair and some of his scalp away from the press. He spent the rest of the week in ICU with a crushed skull and swollen brain. (He never was quite right after that)

Make good, thought out safety rules and stick to them. The machines we work with can inflict some serious damage faster than you can blink. I’m not picking, it’s just a good reminder to all of us to watch out! Tomorrow I’m going to have a look around the shop for other safety issues.

BTW Kathy thank you for sharing your incident, I would have been to embarrassed to admit to it.
 
alrighty......

Warren, I'm thinking you might be on track. I bet I did not have a good hold of the stick. If I am not holding the stick properly I can see how it could get away from me. Jim described it perfectly, it took hold of the metal and BANG, scared the heck out of me. I assumed when the blade quit moving that meant it was literally caught on the metal which it was. How the blade didn't lose any teeth is beyond me. I'm thinking if it had been inclined it could have taken the whole stick away from my grasp and launched it.

...and to your other question unfortunately the blade was running when I ran the rag by it. The blade is hidden behind the safety box it isn't like it was right out in front of me exposed. Believe me I deserve to have my saw taken away from me after that one. It truly was an absent minded thing to do.

The saw is a used Brevetti. I was told by the previous owner that the Italian's have some really fiddly safety precautions that we don't have here so he disengaged some of them. It used to be it wouldn't operate without the clamps engaged but he changed that. Both fingers had to be holding something to verify that both hands were not near the blade before it would operate and he changed that too. The one safety feature it still had was if you tried to lift the safety box that house the blades the motor would cut off. For whatever reason that is no longer working.

Since both blades are contained within the safety box I don't have bits of metal flying out at all, they fly into the bottom of the saw. I am so much more comfortable with this saw than the Deltas that were here when I got here. Talk about flying metal pieces.

I better see about fixing the clamps after this episode it did scare the bejeezus out of me for real. The guy I bought it from was really careful to show me how to use it, it is a very good saw. I only spent $1,500 on it and it cuts like a dream. I think I have let myself be way too comfortable around it for sure. Now I am just scared of it.......
 
Yes David, it is embarassing as heck to admit what a dopey move the rag was. When I saw how it tore through the rag and how close it was to my finger, yikes! Plus if it had pulled the rag toward the blade I would have been a goner, my hand was partially wrapped around the rag. I have a healthy respect for these tools and what harm they can cause. For the life of me I don't know how I could have let myself be complacent enough to not even think.

My wax stick is about 4 inches long now and has needed replacing for a month or so........

Randy, I am with you on cutting metal frames also. I only cut the OEM ones, I order all the others chopped. I also know using the combo blades on metal is hard on the blades too, I should have a separate pair but I just don't. Really I don't cut that many metal frames as a rule. Until this week of course, I took a couple multi piece orders for metal frames.
 
Kathy,
It happens with metal, and like Jim said OEM's are normally a little thinner. I've had this happen several times and normally it's because I haven't supported one side of the moulding. Like when you are just cutting the end off to get started. I've had those little pieces go clang and slap the crap out of my fingers in the past. I really try to avoid that. My clamps are my fingers, but normally I hold the moulding down and towards the fence and make sure that enough is sticking out the other side so I can hold it too.
 
Or it happened because you're a girl!
 
Come on Jerry. You've been a conciderate nice concerned guy untill that crack. Behave. At least she goes into a shop and even knows how to turn the equipment on and off.... :D

My wife stands in the doorway.... doesn't know how to cook either. :D
 
Am I the only one who would never, ever saw an unclamped metal?
No, I am also a member of the never unclamped aluminum society. I think Warren's diagnosis is correct- twisting and catching. The real danger in cutting unclamped aluminum extrusions is that sometimes some shapes under some conditions can snag. This in itself can be unsettling but if you are hand holding the stock in position when it grabs your fingers can be pushed someplace you don't want them to be.

Close calls and a good imagination can be a blessing with power tools - they help maintain a healthy respect for the dangers we tend to forget when an operation becomes routine.

Peter Bowe
 
Kathy,

You need to have the moulding clamps fixed right away, or come up with some other clamping system other than just your hands. Because of the design of the Brevetti, it will "pull" the moulding into the cut, some saws push it away (Some of this is due to a blade's tooth configuration, but your Ultramitre blades should have the proper negative rake). I think what happened is the saw pulled the moulding into the blade and it got wedged between the sawblade and the end of the fence where the blades come through. This probably wouldn't have happened if it was clamped in place.

Hope this helps.
 
Now I feel like I have been playing with dynamite for 3 years and didn't even know it. :eek:

As I think about it I don't think I had much of a cut off on the other end, normally the cut off would be up against the fence but I think I was conserving because I had more than one frame to cut.

After reading everybodies responses I couldn't get up the nerve to cut the ones I need cut, gonna have to do it in the morning. I'm not sure what is required in getting the clamps reattached, I'm going to have to get with the previous owner and ask him. Until then I will have a death grip on the moulding......and I've packed up my second set of blades to get sharpened at ultramitre....and I have a new wax stick on order from my supplier....

Thanks for the advice everybody, I think I have been warned with this incident, don't ever stand at ease around high powered tools!
 
Kathy, you probably thought we were done. We're not.

I think trying to hold a metal moulding without clamps is like trying to brace yourself for a head-on without a seat belt.

But I don't know if you want to accept the advice of a 9-3/4 fingered guy.
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Always give your saw time (a few seconds) to come up to full speed be for cutting. Its easy to pull the trigger and start to cut too soon.
With out the blade at full speed it is easy to catch a tooth. Slam bang stop.
 
Ron

My Ledsome saw has no clamps.

I cut metal on it daily.

I had the same thing happen to me a couple of weeks ago. The blades were dull, the hydraulic pressure was too high, and the OEM metal profile #5 flexed enough to choke out the blade. That is why blades should be belt driven and not direct drive. If the blade gets in a bind, the belts will slip.


I also have a FrameSquare.

It has clamps.

It makes a mess of OEM #5 metal.
 
I have a Pistorius EMN-12 and it didn't come with clamps either. I don't normally have a problem using just my hands as long as both sides of the moulding are supported.

Baer: But Kathy IS a girl! A girly girl.
 
And we are SO lucky that she is.

So, in summary, if your name is Jerry, you don't need clamps. The rest of us do.
 
Originally posted by jvandy57:
Baer: But Kathy IS a girl! A girly girl.
Man, I hope that isn't what comes across cause I have not lived my life as a girly girl. Not that there is anything wrong with that. Becoming a framer has surely allowed me to get used ot using handtools and machinery. I am less intimidated than I used to be, as long as my nail polish is dry and there is no threat of chipping.
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Ron, I hear ya loud and clear. I have used this thing for three years without clamps and feel lucky nothing else has happened.

As I recall the Pistorious's I have seen don't the blades pull down on to the moulding? Where as mine I am pulling the blade toward the moulding. Maybe that is why no clamps on the Pistorious? The guy I bought this saw from has a new Pistorious and it has no clamps. He regrets getting the Pistorious he is always asking to buy this one back.......
 
Originally posted by Emibub:
As I recall the Pistorious's I have seen don't the blades pull down on to the moulding? Where as mine I am pulling the blade toward the moulding. Maybe that is why no clamps on the Pistorious?
Some may say that Pistorious is lowering their list price by eliminating all but the essential items. However, they do sell these saws for many applications, and it is up to the user (under advisement from the pros at Pistorious) to determine what accessories and options they want. The Pistorious has both vertical and horizontal automatic pneumatic clamps available. We have the vertical ones and use them almost all the time.

The blades on the Pistorious do "come down" on the moulding, however, because of the rotational direction, it will tend to pull the moulding away from the fence.
 
Kathy,

Also, possibly the nut was not tight on the bolt. Blade stopped, but spindle was spinning.

Another thought is that if the blade and spindle stopped: This is a heavy duty motor with some decent amps. This might be sigh that the motor needs service. The brushes or whatnot might be worn.
 
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