1/2" router chuck to 1/4" bit some information

reible · Post by **reible** » Wed Mar 21, 2012 4:33 pm

On another recent thread there is some discussion on adapting the speed increaser 1/2" chuck to use a 1/4" bit. At this point the normal means of doing that, a shopsmith purchase, is not available. For reference the thread is at:

https://forum.shopsmith.com/viewtopic.php?t=10087

This got me thinking to the bygone days of my early experiences with my shopsmith, ie 1976 and on.

This is now some from memory and some from notes I dug out from by "blue" note book.

Early expectations were that I would be using my shopsmith as a table router. It happen that I had just gotten my very first hand held router and was leaning that as well as the shopsmith system. The router took only 1/4" bits and at the time the shopsmith took only 1/2" bits.

I had contacted shopsmith and they said that they were not making a chuck for 1/4" bits as the shopsmith had too much torque for them. Sometime later shopsmith again came out with the 1/4" chuck like earlier owners of previous companies had made, or at least close.

So there in my note book was my sketch of an adapter. I have yet to find the design prints which would have a date on it and give me a better idea of when it was built.

It took some digging around to find it as it has not been used in years. I found I really didn't like the shopsmith as a router so began my separate passions for both tools.

I was able to find it and remembered a second issue of why it was never shared with anyone. Well, besides I wasn't into shopsmith routing. It had been designed for what I believe could be a 10ER or early shopsmith router chuck, one without the black finish and designed differently.

I checked how it would work with the current design and found that it could work but should be redesigned. The way it is only the set-screw that holds the bit passes through the adapter and clamps the router bit. The adapter itself then depends on the setscrew to keep it from moving, but that is on the threaded portion of the setscrew.

The original design allowed a set-screw for the router bit and one for the adapter, a much better way to go.

I'm going to post some pictures now so you may need to go back over this a few times to "get" what is/was going on. The first picture shows the two different chucks I have.

[ATTACH]16728[/ATTACH]

Next are the two chucks with the adapter. From this you can see how the adapter would have two set-screw used, one to hold the bit and one to hold the adapter on the old chuck. On the new chuck only the single set-screw would have to do both functions. I'll explore more on that later.

[ATTACH]16729[/ATTACH]

The next shot shows the adapter so you can see the step where the shaft hole and set screw intersect, just for your reference.

[ATTACH]16730[/ATTACH]

Now we can look at the black chuck and the insert in more detail.

[ATTACH]16731[/ATTACH]

From this you can see the adapter will be inset in the chuck and the second setscrew will not have a clean fit on the adapter. Just a little bit longer would have made this more universal.

see next post of more information

reible · Post by **reible** » Wed Mar 21, 2012 4:53 pm

More pictures.

Here is a shot with the router bit in the adapter.

[ATTACH]16732[/ATTACH]

Adapter in chuck.

[ATTACH]16733[/ATTACH]

All together.

[ATTACH]16734[/ATTACH]

A peak into the setscrew hole

[ATTACH]16735[/ATTACH]

So would it work? Maybe?

And after looking at the adapter and new chuck I can see an issue with the setscrew that might be used as the holder for the adapter.... anyone else spot it?

OK now just one more thing to cover coming in the next post.

reible · Post by **reible** » Wed Mar 21, 2012 4:59 pm

For the moment lets assume you all know this and the photo is no surprise.

[ATTACH]16736[/ATTACH]

Note where the end of the shaft is and where the setscrew hole is....mmmmmm.

OK I've got other things to do today so I'll let you think on this for a while.

Ed

JPG · Post by **JPG** » Wed Mar 21, 2012 8:32 pm

Great? minds think alike!

The bronze part is actually two parts. A 1/2 x 3/8 x 1 and a 3/8 x 1/4 x 1 bushing.

Notice the set screw - it is a half dog 'point'.

[ATTACH]16737[/ATTACH]

The bushings are drilled differently. The inner bushing has a hole that allows the set screw half dog 'point' to pass through it so as to secure the 1/4" bit shaft. The outer bushing is tapped with a continuous thread from the chuck(the tap was passed through the chuck threads when the bushing threads were cut).

[ATTACH]16738[/ATTACH]

Notice the set screw 'point' protrudes through the inner bushing.

[ATTACH]16740[/ATTACH]

The middle chuck screw just touches the outer bushing. Since the two bushings are closely tied to the chuck at the front screw, this screw does not actually do much.

[ATTACH]16741[/ATTACH]

wiredone · Post by **wiredone** » Sun Mar 25, 2012 5:40 pm

are you saying that this part is No Longer Available?
http://www.shopsmith.com/ownersite/cata ... em1=514632

reible · Post by **reible** » Sun Mar 25, 2012 6:35 pm

wiredone wrote:are you saying that this part is No Longer Available?
http://www.shopsmith.com/ownersite/catalog/add_to_cart_d.htm?item1=514632

So far as I know no one said this part is no longer available. Did you read that here?

Ed

wiredone · Post by **wiredone** » Sun Mar 25, 2012 7:29 pm

Maybe I was misunderstanding the point of the thread.
This was the quote from reible;
"On another recent thread there is some discussion on adapting the speed increaser 1/2" chuck to use a 1/4" bit. At this point the normal means of doing that, a shopsmith purchase, is not available."

SDSSmith · Post by **SDSSmith** » Sun Mar 25, 2012 9:10 pm

wiredone wrote:Maybe I was misunderstanding the point of the thread.
This was the quote from reible]"On another recent thread there is some discussion on adapting the speed increaser 1/2" chuck to use a 1/4" bit. At this point the normal means of doing that, a shopsmith purchase, is not available."[/B]

I believe this is the part that is not currently available according to one of the members.

wiredone · Post by **wiredone** » Sun Mar 25, 2012 9:55 pm

SDSSmith wrote:I believe this is the part that is not currently available according to one of the members.

Thanks for clearing that up. Think it's post deletion time.