Template Routing

[Jeff Bratt]

I'm making some parts using a router template. But I'm having trouble going around some tight curves on end grain - the diameter of the end semi-circles is 1 inch. The routed surface is very good on the parts when everything goes well, but it's far too easy to get tearout in specific places - and by tearout I mean big, honkin' chunks gouged out of the workpiece. I've figured out I have to saw very close to the final line, leaving very little for the router bit to remove when routing the final shape to the template. So far, I'm doing this on the router table, hand-holding the workpiece. Do I need to change fixturing? Would a shear or spiral bit - with guide bearing - work better? Should I use a spindle sander instead of a router? Any other suggestions?

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Thanks!

[Gene Howe]

A spiral bit would work better. Check your grain direction and go down hill, or with the bit rotation, around a part of the curve. Then come back the other direction for the rest. Also, I use a starting pin and usually start at the beginning of the curve with the down hill cut. Then come back.

[Jerome Hanby]

I'd probably chicken out and use a spindle sander on the curves. If you go with the spiral bit let us know how that works out!

[david brum]

It's helpful to remember the dog fur analogy; you want to pet the dog in the direction that his fur lays down. Same thing goes with routing, hand planing, etc. Going around curves on a router table is especially unforgiving because the bit can get right underneath the grain and lift out a big chunk. The trick is to always be routing in the direction that the grain lays down, usually routing down hill. One common way to do it is to rout the top half of the curve with a flush trim bit (bearing at the top), flip the piece over, and do the lower part with a pattern bit (bearing at the bottom). Example http://mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_flush.html#pattern_flush_anchor.

[Prashun Patel]

A spiral bit will help, but I would try climb-cutting near the end grain if you have a LOT of these to do. If not, then +1 for just bandsawing it close and spindle sanding the tricky areas.

[pat warner]

Would take in 4 thickness stages, min.
Whether x hand or table, that end-grain cut is touchy, but not with a plunger.

[glenn bradley]

I do a fair amount of template routing. Always route downhill (with the grain). Your tear out looks as though it occurred as you rounded the end and started uphill (into the grain). If your bit does not have an upper and lower bearing to facilitate this, pop the template off and stick it to the other side to finish the end cut downhill. With an upper and lower bearing you just flip the blank and the template as a unit, adjust your bit height and proceed. Some of my pattern bits have both bearings some do not. For the ones that do not, if I find myself in a situation where I have to route uphill, I stop and ask myself which takes longer . . . removing and re-applying the template or making a new piece and then removing and re-applying the template. I find when I present things to myself in that light, I usually do the right thing ;-)

[Jim Rimmer]

All good advice so far but I would add to take several light passes. The same effect as cutting closer to the line with the BS.

[Kent Chasson]

If you do decide to climb cut (feed in the direction of bit rotation), make sure you are removing a small amount of material, have good control of the stock, and have your hands well away from the bit. Climb cutting is a great way to avoid tear-out but also a great way to lose control of the work if you make a mistake.

[David Giles]

Based on my experience with template routing, give it up and move to the sander. No matter what you try or how light of a cut or direction of cut, that rotating bit is going to grab the end grain and bust it off. Not good for the heart! I'm sure it could work with some woods in some applications, but you've tried it and it doesn't work for this application. Move on to Plan B.

[Glen Blanchard]

When I need to make a pattern such as you are doing, if I have grain issues, I move to these things.

211072

It is certainly slower than using a router and it will require more pre-finish sanding, but they work quite well and will solve your problem.

http://www.leevalley.com/us/wood/page.aspx?c=&p=59448&cat=1,42500

[Jerome Hanby]

LV should pay you commission, I'm ordering one of those right now. what a great idea.


When I need to make a pattern such as you are doing, if I have grain issues, I move to these things.

211072

It is certainly slower than using a router and it will require more pre-finish sanding, but they work quite well and will solve your problem.

http://www.leevalley.com/us/wood/page.aspx?c=&p=59448&cat=1,42500

[Glen Blanchard]

I should have added that it's also a good excuse to drool over the LV website. :)

[Jerome Hanby]

Got me there too. I had added some stuff to the wish list for the next time I ordered...guess this was that time!. Bought this pattern sanding gizmo along with some extra sleeves, the Narex Skew Chisels, and that miniature router plane.


I should have added that it's also a good excuse to drool over the LV website. :)

[Steve Griffin]

I'd still try a spiral and careful climb cutting first since you are all set up with your router template. Worse come to worse, you can use it for the straight sections and many other projects in the future.

[Jeff Bratt]

I'm making a bunch of these, so really wanted to find a reliable solution. And it was there - amongst all the suggestions. Thanks!

I was very reluctant to attempt climb cutting on the router table when hand-holding the workpiece. And since the template is positioned via those dowels, it doesn't easily switch sides. So I tried a two-step process. First using a hand-held router with a bit that has the bearing mounted on the other end, I cut the two problematic areas - now moving downhill. Then I routed around the rest of the template on the router table. Smooth, easy, and, for the first time, not even a hint of catching. I could have accomplished the same thing using a double-bearing pattern bit .

So I'm relieved to not need to buy an relatively expensive spiral bit w/bearings. But don't worry - I've already bought plenty of new toys for the rest of this project...

Also, a drool-proof keyboard helps when exploring the Lee Valley website - and that template sanding drum looks very interesting.