Machining end-grain

[RogerS]

I know you shouldn't and I wouldn't advise people to do it but I often make climb cuts with the router. I find if you are for example doing an arch which is joined in segments each segment is half with the grain and half against the grain. I sometimes find it easier and less likely to chip if I take small climb cuts moving with the grain then finish with a really fine cut against the grain.

I only do this with the hand held router and work piece clamped securely, wouldn't do it on a router table as it can pull your fingers in if it gets away from you.

I do have a small power feeder for use with my router. Climb cuts are a doddle then but only on straight bits of wood ! And just thinking about it, I guess I might have been able to use the feeder if I was very clever orienting the wood around in a curved path..a damn big 'IF" !

 

[Jacob]

The photo looks like a classic case of climb cutting gone wrong but you say you were cutting against the rotation? I assume then the template was up-facing? I can't see how it could've done that much damage if you were running it the correct way :|. Every split off and snaped piece looks like it would correspond to the router cutter coming into contact with it and "running away" so to speak. ........

I think he let go of it and it "climbed" back at speed. It obviously went in reverse, right to left, after it had reached the end.

 

[Trevanion]

I think he let go of it and it "climbed" back at speed. It obviously went in reverse, right to left, after it had reached the end.

I think you may be right Jacob. It indeed looks like Roger was doing two passes, one pass free-handing to remove half of the material and then another pass bearing on the bearing. It may have unexpectedly caught when he pulled back to perform the second pass and caused the damage in a split second.

Of course, that's just a theory.

 

[Eric The Viking]

Roger, your description, together with the original picture, makes it clear: you were trying to drive the cutter into the end grain, at a fairly severe angle. The effect you got was exactly what I would have got if I'd used a spokeshave wrongly - it dug in and ripped-up grain, just as a spade in the ground might.

The only way I can think of to get a nice result, with a router, would be to reverse the cut direction for that part, where the grain direction becomes a nuisance, either using a bit with both top and bottom bearings, or two templates, so you can flip the workpiece against your existing bit. Sharpness and lack of resin build-up will help, as will fine passes and higher speed of travel (so it doesn't burn). But the curve and the grain together make this really tough to do in a continuous pass.

Climb-cutting has nothing to do with it really, except perhaps to give you a false sense of security - where the grain is helpful to you it should leave a nicer finish, slightly.

I can see how a spindle would help, because of the bigger diameter, also an upcut or downcut so the action is shearing rather than chiselling. IIRC, Wealden do several upcut or downcut bits that will accept bearings, but I've not tried them.

I think the bottom line is that trying to cut that stock at that angle will give that sort of result. Changing the way you do it should "fix" it.

E.

 

[Trevanion]

I remembered today that I've got a funny story about climb cutting gone wrong.

Where I used to work there was an SCM TI145 spindle moulder that had a reverse function and for some reason they were doing quite a heavy moulding using the reverse function because it couldn't be done the regular way without buying new knives etc... If I remember rightly they stopped for tea and turned the machine off, to put the machine back into reverse you have to hold the switch to the left and press the start button, of course, the person who turned the machine back on put turned the switch to the right which was the regular cut direction and fired up the machine with no one the wiser. With the machine running the regular way, they put the first piece through the power feed and suddenly there was a "BRRRRSHWOP" and a "Bang". Spinning at 100 times a second with 9 horsepower of force, the moulder launched the workpiece at over 100 miles an hour through an insulated cladding panel on the side of the shed. I wasn't there to witness it actually happen as I was at the other side of the workshop, I looked around the corner to see what the noise was and I saw two lads, white as ghosts, firstly because they could've killed themselves, secondly because they'd just punched a hole clean through the side of the shed and the boss was a serious loose cannon with a "Hammer throwing habit" :lol:

Fortunately, no one was injured except for the power feed wheels (They got drug into the cutter block) and the insulated sheet. The boss had a massive blow-out once he got back from site work and docked both their pays for a sheet and a workpiece, each.

 

[RogerS]

W...e...l...l.......when I was a mere sprog and a real newbie, I'd got my first router table with an adjustable fence. Tried routing a piece of small timber. Taking very shallow cuts. I couldn't fathom why I kept feeling as if the router wanted to take the timber out of my hands. Felt very strange. I was feeding from right to left. I Googled and looked at videos. I think I even may have thought I had a faulty router going the wrong way in my naivety.

Still I persevered. Until. Until I decided to take a bigger cut when WHAM ! Snatched out of my hand and also buried in the plasterboard wall.

My error ? Fence a long way behind the router cutter and I was feeding the timber in between the router cutter and the fence.