drilling and tapping a new hole in the banjo

[Mark Corkern]

I have a old Canadian General lathe, the person that I bought it from had the 4" riser block put on and had 2 banjos one with a 4" riser and one for the full height without the extension.I use the short one without the extension on the outboard headstock end which has a shelf mounted to a carving vise which comes in very handy, the full height one is a little to tall. So my problem is the banjo that is full height has the bolt that holds the tool rest on the left side, the other one is on the right side, so I was wondering if I could drill and tap a hole on the right side? On both banjos, there is an extra bit is metal where the hole is, what are your thoughts? Thanks

 

[Odie]

I have a old Canadian General lathe, the person that I bought it from had the 4" riser block put on and had 2 banjos one with a 4" riser and one for the full height without the extension.I use the short one without the extension on the outboard headstock end which has a shelf mounted to a carving vise which comes in very handy, the full height one is a little to tall. So my problem is the banjo that is full height has the bolt that holds the tool rest on the left side, the other one is on the right side, so I was wondering if I could drill and tap a hole on the right side? On both banjos, there is an extra bit is metal where the hole is, what are your thoughts? Thanks

Sure, you could drill and tap a hole in the banjo for securing the tool rest......no problem at all, if you have the tap and die set.

Another thought is to get a new banjo with a better clamping mechanism. My Woodfast lathe had the simple screw to bear against the tool rest post originally, and this isn't nearly as good as the Robust banjo I replaced it with. Night and day difference here on how secure the tool rest is.......

-----odie-----

 

[Bill Boehme]

Drill the hole so that it is sized for installing a Heli-Coil tangless threaded insert of the desired size. Because it would be a through hole, the tangless type insert would be needed. This would give the hole much greater strength than just tapping a hole for the screw directly in the cast iron.

You might possibly need a counterbored hole so that the insert will stop at the bottom of the larger hole.

 

[Mark Corkern]

I was thinking about attaching a 1/2" nut to the outside with epoxy or JB Weld, since cast iron doesn't weld very good, then tapping the banjo. Odie so far I am satisfied with the performance of the banjo design, much better the my old Craftsman.

 

[john lucas]

It should be cast and will be very easy to drill and tap as long as you use the correct size drill. Ive.done it a lot.

 

[Mike Johnson]

Drilling and tapping as Bill mentioned above is your best option, using epoxy or JB weld may not be able to provide the forces necessary to secure the nut to the banjo. The set screw will apply a fair amount of force against the chemical bonds of the epoxy on the banjo surface slowly peeling it away from the surface. You also only have the depth of the nut threads to apply the forces to the tool post. You would need to totally encapsulate the nut with epoxy and then apply large amounts of epoxy on a large amount of surface area of the banjo to withstand the forces of the set screw.

Attach a piece of 90 angle to your drill press, secure the banjo to the angle iron using the clamp assembly in the banjo base, this will provide the proper geometry for the hole into the banjo. Drill a smaller pilot hole into the banjo and then drill the proper sized hole for the Heli-coil insert, tap the hole with the proper sized thread pitch tap for the outer thread of the Heli-coil. Install the Heli-coil into the threaded hole. Your biggest expense will be the threading tap and Heli-coil.

 

[Larry Copas]

I have a 260-20 General. I hated the banjo so I modified it.

The tool post tightening handle is a 1/2"-13 thread. I drilled out the existing holes and re-taped to 9/16"-18. The finer thread allows me to clamp the tool post tighter with the same amount of effort. The existing kip clamp handle also stuck out way to far and interfered when I dropped the tool handle to shear cut or scrap. I fabricated my own kip handle which remedied that problem.

The next problem was the tool post hole in the banjo. Sometimes it was hard to slide the tool post up and down. I bored out the hole on my Bridgeport to an egg shape. Not my idea, I copied Oneway.

The final problem was clamping the banjo to the bed. The rod is to small in diameter and springs. I made a few changes but its not quite equal to the Oneway design.

Shown is the OEM kip handle on the left and my kip handle on the right.

 

[Mark Corkern]

Drilling and tapping as Bill mentioned above is your best option, using epoxy or JB weld may not be able to provide the forces necessary to secure the nut to the banjo. The set screw will apply a fair amount of force against the chemical bonds of the epoxy on the banjo surface slowly peeling it away from the surface. You also only have the depth of the nut threads to apply the forces to the tool post. You would need to totally encapsulate the nut with epoxy and then apply large amounts of epoxy on a large amount of surface area of the banjo to withstand the forces of the set screw.

Attach a piece of 90 angle to your drill press, secure the banjo to the angle iron using the clamp assembly in the banjo base, this will provide the proper geometry for the hole into the banjo. Drill a smaller pilot hole into the banjo and then drill the proper sized hole for the Heli-coil insert, tap the hole with the proper sized thread pitch tap for the outer thread of the Heli-coil. Install the Heli-coil into the threaded hole. Your biggest expense will be the threading tap and Heli-coil.

I addition to the nut I was going to drill and tap the banjo that way it was threaded thru the nut and banjo, I thought that would negate any extra pressure.

 

[Mark Corkern]

I have a 260-20 General. I hated the banjo so I modified it.

The tool post tightening handle is a 1/2"-13 thread. I drilled out the existing holes and re-taped to 9/16"-18. The finer thread allows me to clamp the tool post tighter with the same amount of effort. The existing kip clamp handle also stuck out way to far and interfered when I dropped the tool handle to shear cut or scrap. I fabricated my own kip handle which remedied that problem.

The next problem was the tool post hole in the banjo. Sometimes it was hard to slide the tool post up and down. I bored out the hole on my Bridgeport to an egg shape. Not my idea, I copied Oneway.

The final problem was clamping the banjo to the bed. The rod is to small in diameter and springs. I made a few changes but its not quite equal to the Oneway design.

Shown is the OEM kip handle on the left and my kip handle on the right.

View attachment 31543

Larry my banjo has only has the built out place where the threads are on one side that is why I was thinking about putting a nut on the outside. The thickness of the housing is about 3/8" thick, it might be thick enough but was going to beef it up a little.

 

[Bill Boehme]

I fully agree with Mike Johnson. I doubt that the JB Weld epoxy will hold for very long. If there is ⅜" wall thickness, then that should be sufficient especially if it is reinforced with a Heli-Coil.