Spiral router bits

[andrew whicker]

Are spiral router bits less picky of grain direction? I'm looking into buying one with a bottom bearing for template work, but the price is $150. I'll pay if it is worth it in results.

I'm making a 90 degree bend out of walnut. Using a template to cut out of hardwood. Grain is constantly changing.

Thanks

[John TenEyck]

The cleanest cuts I get are climb cutting with a handheld router. Spiral bits cut cleaner than others, but I don't find them necessary for edge routing with the way I do it. To safely climb cut you need to first cut out the workpiece to within about no more than 1/8" of the template. I typically use a 3/4" diameter shear cutting bit if there are no tight inside corners.

John

[Robert Cherry]

They are less persnickety than a straight bit, but you still need to use care around tight end grain cuts as they will still bite. I used a 1/2” carbide spiral bit to cut these back chair legs with good success, but still had a few where the bit grabbed.

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[Warren Lake]

Robert looks like too much overhang, not very good jig support but more important you are not carving the material away it shows you are doing it on one pass. you climb cut and sort of let the router float then when enough is gone go back forward into it. Normally I would leave .030 approx over the template but do it a few ways and with more material there the climb backwards carve away works till close then a forward pass.

[Jack Lemley]

I love my spiral bits. I have Whiteside 1/4" shank with bearing, 1/2" shank with bearing and a number of 1/2" shank no bearing bits.

Jack

[Neil Gaskin]

I also use whiteside spiral bits for pattern cutting. I’ve been very happy. I can’t remember the last time I used one of my straight knife flush cut bits.

[Mike Hollingsworth]

Robert looks like too much overhang, not very good jig support but more important you are not carving the material away it shows you are doing it on one pass. you climb cut and sort of let the router float then when enough is gone go back forward into it. Normally I would leave .030 approx over the template but do it a few ways and with more material there the climb backwards carve away works till close then a forward pass.

translation?

[Warren Lake]

too much material left on to trim

poor support for the router easier for it to tip

carving backwards, might not make sense but running the router backwards to reduce down to final, it will tend to float likely leaving a bit of material then a final clean going forward


I was thinking hand held router, like John I get clean work that way, you wont climb cut on the table. didnt see this was on a router table

[Dave Cav]

Could Robert's chair legs be safely cut on a shaper with an insert head and a pilot bearing?

It looks pretty hairy any way you cut it; I might be more inclined to pattern sand it, at least the end part.

[Peter Kelly]

I'd either freehand this on the bandsaw with a scrolling blade and sand to final or with a pattern jig if you've a lot of them to make.



A top-bearing pattern bit inverted in a router table is asking for trouble, especially with small or complicated parts.

[glenn bradley]

I do alot of template routing and it involves a lot of curves (Greene and Greene). I find this bit serves me best, YMMV. The top and bottom bearing allow me to always route down hill. I can even skip reversing grain patches and come back for the other side.

[andrew whicker]

That's a cool idea. I like being able to see the grain, but I suppose you could mark the uphill / downhill sections so that you know where to start and stop when the template is 'upside down'.

[andrew whicker]

Why are people having better results climb cutting with a handheld router vs a table? I have the same router for both table and handheld (I have two Bosch 1617's).

[Steve Demuth]

Why are people having better results climb cutting with a handheld router vs a table? I have the same router for both table and handheld (I have two Bosch 1617's).

It's question of mass and control. If you're using a handheld full size router, the workpiece will be clamped down solidly, and the inertia resisting the tendency of the climbing bit to want throw something is the mass of the router (typically much more than the mass of the piece of wood being cut) plus the addition of your very firm grip on the router. If you're climb cutting on a table, the router is fixed, and it's the much lighter, and much less firmly gripped workpiece that the bit is try to throw.

That said, the only climb cuts I'm really comfortable with involve a waste I've cut Down to 1/16" or less on a bandsaw pattern jig, or done with a feeder. I really hate ballistic missiles in the shop.

[Warren Lake]

Andrew better results is because you are pulling a router backwards or letting it float backwards while holding it, its opposite to the direction of cut, you are not cutting up into the grain (almost out cause of the small radius bit is turning out more than a bigger cutter would be turning forward more) there will be less blow out because the material is not really in front of the bit, its gone, you are cutting into material on the back side of the bit. spiral is better its cutting accross at an angle so its like holding your hand plane at an angle. Two flute can work fine at times as well. Once I started on spiral for certain work I never bought another two flute. For other cut out and plunge stuff I still bought two flutes.

I dont have an exact way I do it, depending on what you are doing you might have a few approaches and directions on one piece. It relates to how you are cutting and even your overhang amount. I cant explain it that well but give me a router and I know what i will do for each situation and type of cutting. Im often going backwards first then there is very little material left for a final forward pass, then it depends on how you are cutting into the grain, if its an angle cut down hill I likely wont do it at all, angle cut up hill into the grain then ill do it for sure.

Some stuff you really need to hang on or at least be braced well enough its not going to run on you. Some stuff where im climbing where I could not go forward without blow out and ive rested the heal of my left hand on the template then the heal of my hand works like as a pivot point that gives you extra strength and smoother motion to stop it from running on its own, you are allowing it to move instead of it taking off. Ive done this on cuts where my final had to be a climb cut so I knew there would be no forward pass clean up.

Your jig has to be right for what you are doing, other variables are if you are working with a bearing on the end or base insert up top. Ive never had a spiral bit with a bearing on the bottom, I did alot of work, from the prices someone quoted the tooling would have been too much as I went through tons of bits. Ive also run off the shanks of bits right on templates as well. All my templates are 3/4 baltic.

All of this is based on having a good amount of time and feel for the tool. I am safe with it for what I do but it may not be the case depending on the persons experience. Also if you use the Porter cables as an example the big model whatever number it is I have them in plunge and regular. I dont do this stuff with a plunge router becuse they are made with the handles high and its poor for this type of work. The other model where you rotate the motor to raise it up and down have good heavy handles that go right down to the base of the router and its more stable. Cant remember the model numbers but the point is high handles not so good.