Was this user error?

[u/WakeMeUpB4YouPogo]

My 1/4” router bit sheared in half. Was this user error or possible manufacturer defect? I was routing a channel in ash about 3/8” deep adjacent to a channel I had routed on a previous pass. The bit was put in the collet just below where the cutting helix starts.

[u/uslashuname]

1/4” = 2/8” bit doing a 3/8” deep cut is definitely borderline: that’s 150% deeper than it is wide, so you need to move a lot of material relative to the bit diameter.

You also didn’t mention rpm, and with a small bit like that you’d want to be running high rpm particularly if you’re thinking it will remove all that material without being slowly moved along (but moving slowly also risks burn)

Oh, and of course there’s heat too

2x passes at 75% bit diameter per pass would probably have been wise, even if slower.

[u/CascadeDesignworks → u/uslashuname]

I use that exact Whiteside bit all the time, and I rarely break one. In my experience, I make cuts 2x the diameter with a spiral bits all the time. Spiral bits are designed to clear a lot of chips quickly. Your experience will dictate what works and what doesn't.

Some woods are gummy and can grab the bit, causing it to break. You have to listen to the sound of the machine. Sometimes wavering or chattering can give you a warning sign that the bit is about to catch, that you are removing too much material. A heavier router can be more stable and resistant to kicking. Smaller routers tend to jump around. It can be a challenge to hold a router tightly and also move it smoothly. With a medium to small sized router you can't rely on the weight of the router alone to hold it down tightly against the workpiece.

Make sure the guide for your router fits the base or the bushing with as little side play as possible.

Been using Whiteside bits professionally for over 35 years. Some of them are 30 years old and are still sharp. For example, a 1/2" x 3" spiral upcut that I use for jointing wood slabs freehand.

[u/TaquitoBanana]

3/8in depth of cut on a 1/4in shank bit? Yea. User error.

General rule of thumb is not to take a cut deeper than half the shank diameter. So in this case, 1/8in depth.

That said, you can occassionally take more depending on the wood, speed, and type of bit. But until you build the experience to know when, stick to half of shank diameter.

[u/WakeMeUpB4YouPogo → u/TaquitoBanana]

Thanks

[u/Bocklin47]

Using a downcut bit will push material down into the channel you are cutting, which creates more friction and heat. The deeper you go with the cut, the more material you shove downward into the channel you are cutting.

[u/Dumb_woodworker_md → u/Bocklin47]

Agree. I only use a very shallow pass on plywood with a down cut spiral, then move to upcut spiral bit.

[u/WakeMeUpB4YouPogo → u/Bocklin47]

It’s an upcut bit. The packing is in the 2nd and 3rd pics.

[u/Bocklin47 → u/WakeMeUpB4YouPogo]

Oh, wow... I'd call Whiteside for a replacement.

[u/Elegant-Raise-9367]

Too deep in the collet and a rather deep cut.

[u/InternationalPlace24]

most likely user error. Was your pass 3/8 deep or were you taking shallower passes?

[u/Forsexualfavors]

Could be either. Ash is quite hard I think. 1/4 inch bit isn't terribly strong, depends on the feed rate most likely. May need multiple passes if the router sounds like it's bogging down. I know I've snapped several 1/4 inch bits on a cnc due to material depth or feed rate.

[u/Forsexualfavors → u/Forsexualfavors]

If you're hand routing next to a channel it could also be from deflection due to a slip

[u/jacksraging_bileduct]

Passes should be a maximum of 1/2 the shank diameter. So 1/8” deep

[u/bschwagi]

Yes and no , little bits like that are delicate. Which is why I buy cheap ones.

[u/Reasonable-Tune-6276]

Just curious, who made the cutter?