Est. 1998 — 27 years of woodworking knowledge
turning star knobs
I've seen numerous videos for making star knobs using various bolts nuts, saw hole jigs, etc.But it occurs to me that there ought to be a simple way to do it on a lathe with some off-center turning as part of the process. Has anyone tried it?
Joyner Jig
Seems like a Joyner Jig could be set up on three axes to do this pretty simply.
Re: turning star knobs
Rather than doing off-center turning, it would probably be easier to turn the knob on whatever stud you want to use for the knob. Then use an indexing set up to hold the knob in place while you pivot in a router on a hinge to form the scallop. That method lets you have as many lobes on the star as your indexer can do.
Re: turning star knobs
Yes,your suggestion would clearly work. But what I am after is more along the lines of Gary's suggestion because I have in mind to do the job entirely on the lathe. Otherwise those other methods using hole saws etc. at the drill press are ok.
Re: Joyner Jig
Good idea! Didn't know there was something like a Joyner jig out there. It does seem a bit overkill for what I'm after. So I would probably just rig up something similar for this one application.
Clif showed us how to do this...
...with homemade jigs in December 2010. See https://photos.app.goo.gl/rhrb4qGm63ymJGQf6
Re: turning star knobs
Actually, I was suggesting doing it all on the lathe. One could use magnets to attach a hinge to the bed (assuming it is not a Robust lathe) and use it to set up a trim router to pivot in to cut the scallops. Alternatively, one could put a small table on the ways and setup a sliding trim router jig like the basic function of the Shopsmith duplicator (without the guide/follower on the puck).
Re: turning star knobs
Oh, I sort of see what you mean. But there's still a router, which is to say a machine different from a lathe, involved-- not that that's the end of the world. I still want to do it with only offset lathe turning. Do you see an advantage using a router over what I have in mind ?
Re: Clif showed us how to do this...
I looked at the link: seems more like a finial box than what I have in mind--e.g. , I don't see the scallops for a star knob.
Re: turning star knobs
Sorry, but I can't figure out what your current approach is other than the only tailed tool being a lathe. I have a set of jigs for making trivets. In one configuration, you cut concentric circles half way through the blank. Then you re-configure the jig so that it is offset and you cut concentric circles about an offset center. You wind up with 3 touching circles sets on one side and the one centered set of rings on the other. You could certainly make a jig to do pairs of star knobs at a time. With the knob head turned round to the size that you want (and attached to the bolt that you are using for the threads), you can bolt the knobs to a plate using the threaded bolt. Use a Forstner bit in the tailstock to cut the scallop in the 2 knobs. Loosen the knobs and rotate them to the next position and cut the next scallop. Continue until you have as many scallops for the star knob as you want. Doing them 2 at a time helps keep the Forstner bit from wandering as you drill. If you do not want the scallops to be straight-sided, then you can shape them as you want with turning tools of your choice, but I would still do the main scallop with a Forstner to get better consistency. Putting some moderately coarse sandpaper under the knobs will help keep them from turning while you drill the scallops.