Master Tenon jig for the Shopsmith

[godavid2]

Am trying to remake the wooden trunnion for the MT jig. Can someone tell me how to cut the slot in the trunnion? thanks

[JPG]

Am trying to remake the wooden trunnion for the MT jig. Can someone tell me how to cut the slot in the trunnion? thanks

:eek:VERY carefully!:D

I made one by using the pivot hole and rotating the 'trunion' slowly/manually. The bit will have a great 'tendency:rolleyes:' to grab. I 'nibbled' my way through and cut the inner and outer arcs separately(used a bit smaller than the slot).

I also 'counter routed' the slot.




Make sure yer religion is intact before attempting!;)

[godavid2]

I wondered how tricky it might be. Now I'm sure of it. I had thought about drilling the pilot hole for the slot and then routing the remaining arch. It would be free hand which is very tricky for me, anyway. I also wonder about mounting the routing bit from above. thanks for the help.

[forrestb]

You might try using a jigsaw to cut the bulk of the wood before going to the router.
Forrest

[dusty]

Am trying to remake the wooden trunnion for the MT jig. Can someone tell me how to cut the slot in the trunnion? thanks

Yes, you could probably do this with a router if you are either good or lucky but I believe it is time to give up the power tool approach UNLESS you are interested in a pin router.

It sounds to me like this would be an ideal task for the pin router.

However, there are other ways.

My first approach would be to use the drill press and the proper size forstner bit. Cut the shape of the wooden trunnion and then drill a series of holes using the drill press and the fence. The fence is being used to get proper spacing from the edge.

Once the series of holes have been drilled, this becomes a file and sand paper task.

[dusty]

After posting the above, I got to thinking about this. It could be easier that we might imagine.

First you must have a sacrificial table on your drill press, clamped tight so that it won't move.

Then a 4 5/8" square piece of hardwood 3/4" thick.

Drill a small screw hole in one corner (3/4" from the sides). This will act as a pivot point for now but will get drilled out to a 1/4 through hole before we are done.

Locate the pivot point on the sacrificial table. It should be 3 1/4" from the drill line. Using a small screw, attach the trunnion to the sacrificial table at that point. This is a critical point. Get it right to match your trunnion (Miter Master).

Using a sharp, 1/4 brad point or forstner bit, begin drilling holes as you pivot the trunnion. Done carefully, a little bit of hand sanding and filing should finish the project.

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WARNING: Double check the dimensions against your Tenon Master. I do not know that all Tenon Masters are the same.

[dusty]

Is this an application where a router bit could be used safely in the drill press mode after all of the holes had been predrilled.

Because of speed limitations, I have never used my Shopsmith as a router but this seems like a place where that could be done.

I don't have a 1/4" router bit so I cannot test that idea. I did, however, do a sorta proof run using a 1/4" brade point and I think the results are a "go".

You tell me.

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The pivot hole needs to be enlarged. The one corner needs to be rounded off. The routed slot needed to be dressed out. The process will work.

I was to close to not go one step further. I chucked a router bit that I do have to verify that this would work on the Shopsmith. The setup was not as cool as it would be with a router but it worked. I had a lot of chatter but maybe that is the result of incorrect speed for the router bit.

I'd send this to you david but it would do you no good. The arc is 1/8" offset from where it should be. Like I said, double check the measurements if you are going to do this.

[reible]

That is a very small piece to be hand routing. If you haven't done it yet then start with a larger piece then cut it to size after routing.

Check this post for an ideal way to do this.

https://forum.shopsmith.com/viewtopic.php?p=133582

Ed

[newportcycle]

You may want to try one of these router circle jigs http://jaspertools.com/productsdetail.cfm?SKU=673046002002&prod=Model-200 Circle Guide&cat=Circle Guide I purchased one of these years ago for making speakers, works like a charm. Im sure this will spark a few DIY ideas for the more clever members here.

[dusty]

You may want to try one of these router circle jigs http://jaspertools.com/productsdetail.cfm?SKU=673046002002&prod=Model-200 Circle Guide&cat=Circle Guide I purchased one of these years ago for making speakers, works like a charm. Im sure this will spark a few DIY ideas for the more clever members here.

These guys offer some pretty neat looking tools but at the same time they look like tools that I would have to learn every time I pick one of them to use.

Since I don't cut circles every day, the (re)learning process may be prohibitive.