A Homemade Expanding Anchor

[rgsparber]

My local hardware store has a modest selection of expanding anchors. If I am free to drill the required hole, these anchors work great. But there are times when the hole exists and I just need to be able to thread in a bolt. That is where it is nice to be able to make my own anchor. The design presented here is not as strong as the store-bought variety.

If you are interested, please see

https://rick.sparber.org/anchor.pdf

Your comments are welcome. All of us are smarter than any one of us.

Thanks,

Rick

[mklotz]

This type of anchor works well to fix things to the outboard end of the bore of the lathe spindle. Examples of "things" might be a dividing disk or a hand crank for threading up to a shoulder.

Done with square-section stock one can make fences that lock into the T-slots on a machine. For example...

Miniature milling table accessories

[rgsparber]

I suspect the genesis of this anchor was from seeing an attachment to a lathe. It might have been in the Bedside Reader series.

A spreading anchor for a T slot sounds very useful. Do have to be careful not to force the top of the slot since it could chip out.

An adjustable parallel is a close cousin.

Thanks Marv!

Rick

[jdurand]

I suspect the genesis of this anchor was from seeing an attachment to a lathe. It might have been in the Bedside Reader series.

A spreading anchor for a T slot sounds very useful. Do have to be careful not to force the top of the slot since it could chip out.

An adjustable parallel is a close cousin.

Thanks Marv!

Rick

I made my lathe attachment based on bicycle handlebars.

Here's the handwheel attachment for the lathe.

[Lee Bell]

It has worked just fine in millions of bicycles over the years all over the world to hold the handlebars tight too.

[Crusty]

Hey Marv,

The best way to thread up to a shoulder is to run the chuck and lead screw in reverse with the threading tool mounted on center but upside down in the toolpost. You start threading at the shoulder and feed outwards to the end of the part and so don't have to worry about crashes.

If the chuck and the lead screw rotate the same direction it will be a right hand thread - if opposite directions then it will be a left hand thread.

[mklotz]

Hey Marv,

The best way to thread up to a shoulder is to run the chuck and lead screw in reverse with the threading tool mounted on center but upside down in the toolpost. You start threading at the shoulder and feed outwards to the end of the part and so don't have to worry about crashes.

If the chuck and the lead screw rotate the same direction it will be a right hand thread - if opposite directions then it will be a left hand thread.

As far as I am concerned, a thread to a shoulder is just an indication of a bad design. In years of building stuff, I've never had occasion to need to do it. It's almost always possible to arrange things so conventional fasteners can be used.

Besides, my lathe has a screw-on chuck so cuts while it's running in reverse aren't the best idea.

[Tuomas]

Great tip.
That works nicely if you want to make telescopic builds and need a solution to lock parts to desired position / lenght.

Thanks!

[Gadgeteer]

I repurposed a handlebar anchor to secure 3/4" poly pipe inside the bullet point puller for my ride-on yard irrigation trencher. It just happened to fit its second purpose, perfectly.