Ouch...!

[David C]

I insist that my students work out correct feed direction for every different form of cut befor switching machine on.

Slow but hopefully safe.

David C

 

[PaulO]

I have caught my right ring finger in a similar accident. Routing a groove for the bottom of a box, I was making a test cut with a small piece of scrap. The problem wasn't really to do with making a climb cut as I was cutting a slot. Althought the piece was obviously grabbed because the small scrap twisted away from the fence. The cause of this was that my scrap piece was just too short. I will now make a suitable length scrap piece if none is available. A feather board would have helped, as would a push stick, but the primary culprit was the test piece.

I am just glad that I learnt this lesson with a small 1/8 straight bit, as a large rebating cutter would have removed the end of my finger. As it was all I suffered were about ten paper cut size slices in the tip of my finger.

 

[David C]

Paul,

Glad to hear cuts were minor.

Single pass groove cutting introduces the second law of routing feed direction, which is different from the first. (first i.e. to avoid climb cutting for all but the finest finishing cuts).

In one direction the work will be pulled tight against the fence and in the other it will pushed away from the fence, with resultant disaster.

One has to consider the forces acting on the work as half the cutter circumference cuts the end grain at the end of the slot.

Since both edges of the cutter are cutting in opposite directions, the usual rule of feeding the work against the cutter rotation does not produce an answer. This first law only works when part of the circumference is exposed to the work.

David C

David

 

[Chris Knight]

Gidon, but such a pretty picture :lol:

 

[gidon]

Thanks Chris - it was that or read some very boring paper !
Cheers
Gidon

 

[irishthump]

I did something similar about 18 months ago, with much worse results...

I was trying to round off the edges of small piece of pine (roughly 100x50x18) I was pushing it against the fence, no feather board or push stick! The bit hit a small knot in the stock and threw it, but my right index finger and thumb made contact with the bit. All because I was in a rush and did'nt want to go looking for the feather board or push stick.

Lost the fingernails on both index finger and thumb, and the tips of my fingers looked like mincemeat. Hand was bandaged up for best part of a month. Luckily, it healed excepionally well, considering the damage. I have lost a little sensation in the tips of both thumb and finger, but nothing major, I was damn lucky.

It took me over a year before I had the courage to use the router table again.

Sorry for the long winded post folks, but it taught me, those flesh eating machines we use are VERY unforgiving.

Be safe!

 

[brianhabby]

It's interesting these injury posts always get a lot of interest. I suppose we all need to be made aware of the dangers lurking in the workshop waiting to pounce when we least expect it.

Surely the easiest way is to cut the right hand side of the groove using a smaller cutter than the finished size of the slot, then move the fence over and cut the left hand side of the groove. This way the wood is moved from right to left as normal.

Shultzy,

The reason I was flipping the piece was to ensure the groove would be centred, moving the fence would not ensure this.

As it happened, when I though about it, as long as the groove was reasonably close to the centre then it would be okay. It didn't need to be centred, it just needed to be the same distance from the face edge on each piece.

This is what I finished up doing, just passing the work through the cutter (with a push stick) once. The job is now finished and I've learned another safety lesson.

Dan,

I said I might use a slot cutter like you recommended but then realised I needed a stopped groove so had to use the straight cutter after all.

regards

Brian

 

[brianhabby]

Gidon,

Thanks for the pictures, they are going on my workshop wall,

regards

Brian

 

[Shultzy]

The reason I was flipping the piece was to ensure the groove would be centred, moving the fence would not ensure this.
Brian

In that case Brian cut the left-hand side of the groove first and the turn it around. That makes sure the cutter is cutting in the right direction.

 

[Anonymous]

The reason I was flipping the piece was to ensure the groove would be centred, moving the fence would not ensure this.
Brian

In that case Brian cut the left-hand side of the groove first and the turn it around. That makes sure the cutter is cutting in the right direction.

Ahhhh the light is now on.
I was getting awful confused as to what was right way to do it, now I see. Thanks Shultzy.

 

[brianhabby]

Well I won't be making that mistake again anyway. Of course I will continue to make mistakes - like the one I made today...!

Have you ever hit your finger when knocking nails in...?

Guess which finger I hit today - no prizes :roll: :x :!:

I'm glad this week's over

regards

Brian

 

[Digit]

I lost the end of my right index finger years ago and I think the surgeon was looking for some practise as he insisted that the top two joints on the finger and the next should be removed.
No way.
He informed that the nerves would never regenerate and the fingers would just get in the way.
3 months later I tapped the end of the index finger with a toffee hammer and I thought my arm was on fire!

Roy.

 

[OPJ]

A groove doesn't necessarily have to be perfectly central, in most cases. As long as it's close or it looks okay and you reference ALL your work from the same face or edge, everything will work out fine.

Norm seems to like "centralising" his grooves on the table saw with a dado blade, where there isn't the exact same issue with regards to kickback and rotation of the cutter/blade.

 

[Rich]

The incident that made me wary of machinery that turns happened when I was 18, on day release at college, the class was turning slip fit gauges that needed a superior finish before hardening with cobalt, I had been finishing with emery cloth and reached over the workpiece to "ascertain" the finish, the cuff of my smock got caught in the jaws of the lathe, luckily the smock was not to strong and the sleeve was ripped right off, I was very shaken but lucky,had the smock been stronger my left arm would no longer be here.
regards, Rich.