I’m working on a turning where I want to glue in contrasting pieces of wood. I want to make the channels 1/4” wide and they’ll need to be around 3/4” deep. The cuts on the walls will need to be nice and clean since any inconsistencies will show up as gaps after the piece is turned.


One last thing... the cuts should stop short of the ends.

Any ideas?

Got a milling machine available? Going 3/4 deep with a hand router will require going in steps, which tends to lead to a high chance of steps on the walls showing. Best bet would be a router table with stop blocks attached to a fence to rigidly stop the work where you want it and position the mortise properly. Three 1/4" depth cuts should do it, and so long as the fence and stop blocks are locked down nice and solid you shouldnt get much of a step on the walls.

If you have a mill though, full 3/4" depth of cut with a slower feed, perfect results :D

epicfail48 nailed it - router table with stop blocks.

Your explanation is a bit vague.
Are these channels longitudinal or circumferential? I'm thinkin' they run the down the length, but stop short of the ends. I don't know how you would set up a router table with "stops" to do this as the distance from the cutter would vary as the circumference changes.
Not only that, the depth would vary with the shape of the turning.



Sounds like a job for a CNC router to me.


If I had to do it by hand, I'd lay down a piece of 1/4" wide tape to establish the width, score them with a sharp knife and then hog out the interior using chisels, a Dremel or any means on hand. The depth is still going to be an issue since the shape is curved. The insert would almost have to have the same curvature to fit and then be sanded or turn off flush later.


A sketch would eliminate this shooting from the hip advice, since I really have no idea what it is you want to do.... just sayin'

You could build a box over the turning with a gap in the middle to set over the turning while on the lathe. Then you could either set up guides for the base of the router or use a template guide. Cutting the depth will take multiple cuts even if you have a spiral bit.

I know what it means to assume, but the assumption was starting with a square piece of wood, routing the slots in some or all of the faces, stopping short of the ends, gluing in the contrasting wood, then turning on the lathe to whatever profile desired. Seems like a pretty tricky thing to do the grooves after turning?

Sounds complicated. I recently took Ogres advice and tried an upcut spiral router bit for some 1/4" slots I was cutting. I was surprised how well the spiral bits worked. One of them may be helpful on your project. just a thought. Good luck!!

personally, I have had some issues with tasks like this on the router table as described. It can get very squirrelly during the plunge and exit of the bit, often leaving a little oops there. a much better solution is to machine a groove on the ts with a dado blade, then install blocks in the end.

In my effort to keep it brief, I was light on detail, but Alchymist nailed it. Start with 3 x 3 x 12 stock, slots cut lengthwise in the faces, stopping short of the ends. Contrasting wood then gets glued in. The whole enchilada gets turned later. When complete, the narrowest part of the turning will be about 1-5/8", so the slots need to be deep enough to accommodate that.

Unfortunately, I don't have a mill...

If routing is the way to go, any thoughts/recommendation on the best bit? Two flute bits seem prone to chatter. I also see three flute and spiral. I have a spiral bit, but it seems to cut really slowly.

Any suggestions?

If you start with square stock any straight flute 1/4" bit that's sharp will work OK. You can hand rout them with a plunge router because of the "stopped" end. Doing it on the router table requires additional skill because of the plunge and it can get "squirrley" as mentioned. The 3/4" depth isn't an issue with several passes at 1/4" deep.


Practice your method on a scrap first so see how it feels IF you've never done a plunge cut that's stopped. Other than that, it's really pretty straight forward.

I would think 3 inches would be enough for a stable router cut. Attach a fence to the router base, clamp the blank between bench dogs. Figure out how to clamp the stops to the bench.

I've done this many times on the router table, but to make mortises. The slots were good enough for mortises because they'd end up hidden, but they were never perfect.

The plunge router makes sense, except that I don't have one. Perhaps it's time to make the plunge...

If you clamp a scrap that's out from the fence at the width of the workpiece, and long enough to make a "pocket" to drop the workpiece into so it can't shift away from the fence, it will be more controlled than if you hand held it and dropped it down on the cutter. Then use stops at each end for your slot limits. It's all about taking what ever steps you need to assure accuracy on cuts like these..... but not overthinking the entire process, maybe a fine line?

Recently read a bit about the horizontally mounted routers and it looks like a promising setup. Theres several videos on youtube about them and building them. Maybe that setup would make the job easier all though you would of course have to either build or buy the table.

https://www.mlcswoodworking.com/shop...ter_table.html

I added a plunge base to my Porter Cable 690 router, maybe you can do the same with whatever router you have.

I am not a turner nor do I want to be.
I think what you really want to do is called segmented turning. Glue your pieces up and then turn them.