Jig Borer - I reveal my Ignorance and Stupidity

[Bill Gruby]

Yes Bill they do, but it is not recommended practice. You won't throw it off as in the spindle off the machine but you will throw the accuracy off if you push too hard. That's why they call it a Jig Bore and not a Jig Mill or Universal Mill. LOL

"Billy G"

 

[Billh50]

True. it is only for very light milling. Never did push em when milling.
For hole locations they are great. Ran a jig grinder also for locating and sizing holes after heat treating.

 

[Nick Hacking]

So when I want to make a hole (or series of holes) at a precise location (or series of precise locations) I should load up the jig borer with either a drill bit or an end mill and use it for making accurate vertical holes, using the x,y and z indices and my rotary table as required.

Once I start doing any milling operation where there's sideways force on the tool, I should stop and think if this isn't an operation better done in the Bridgeport?

Is that a fair synopsis?

It can hold tooling up to about 12 mm diameter, and of course, using devices such as fly cutters, it could handle bigger holes than that. But always where there's little or no sideways cutting: just straight up-and-down?

It is a fairly small machine, especially in comparison to the mill.

 

[Billh50]

You got it. Only milling that should ever be done on a jig bore is only a couple thousand removal. Just a finish cut. Any more and it can throw things off.

 

[Nick Hacking]

So when I want to make a hole (or series of holes) at a precise location (or series of precise locations) I should load up the jig borer with either a drill bit or an end mill and use it for making accurate vertical holes, using the x,y and z indices and my rotary table as required.

Once I start doing any milling operation where there's sideways force on the tool, I should stop and think if this isn't an operation better done in the Bridgeport?

Is that a fair synopsis?

It can hold tooling up to about 12 mm diameter, and of course, using devices such as fly cutters, it could handle bigger holes than that. But always where there's little or no sideways cutting: just straight up-and-down?

It is a fairly small machine, especially in comparison to the mill.

This is it.

To show the scale I've put a 14 mm spanner (wrench) on the table.

It's very simple: the spindle is fed from the motor via an idle wheel. Different combinations of drive and driven pulley wheels can be selected to alter the speed, in the usual way. The head can be tilted in the coronal plane (but not saggital). The knobs on the top move the spindle in the Z-axis. The two on the side facing the camera move the table in the X-axis and rotate the table. The knob on the front of the machine moves the table in the Y-axis - and that's all there is to it: a sort of elegant simplicity.

Thanks again for all of the advice,

Nick

 

[Billh50]

That's a cute little thing !

 

[Bill Gruby]

It looks like a Watchmakers Jig Bore. Mucho Precision.

"Billy G"

 

[rzbill]

Went to Moore years ago during a project. For me, it was like going to the 'church of precision'. I felt like kneeling and chanting "I am not worthy".

Nice machine you have there although may not be applicable to the needs of most hobbyists.

 

[benmychree]

I had a Pratt & Whitney #3 jig borer in my shop and used it for anything but jig boring; it was large capacity and had all geared speeds with a 4 speed motor; we used it as a big milling machine. Sadly, after I sold the business, it was scrapped.

 

[Nick Hacking]

Thanks for the kind comments, all.
I hope you can see, now, why I want to use it but definitely don't want to abuse it.

The jig borer was about half the price of my old Bridgeport. If I had bought the Bridgeport first, I'd never have spent the money on it but I'm really glad that things turned out as they did because it's not the kind of thing that I'll ever voluntarily part with. I suppose that's the great advantage of being a hobby machinist: I can afford to allow sentiment and emotion into my decision-making. I'm not doing this for a living (if I did, I'd be a lot thinner than I am right now).

If I come up with a project that can use the jig borer's capabilities sensibly, I'll post it up on this forum.

I really appreciate the advice and encouragement that I've had on here. Thanks again to all of you.

Kind wishes,

Nick