Sometimes that's what it takes.

***I generally prefer a spun cup to a CNC cup***

I prefer a "spun" cup maker!

I much prefer spun cups (copper my favourite metal): Sherwood, RNT2, Riser.....they are all excellent!
Buy all of them....but don't tell your wife...

For that certain indefinable feel, "spun" trumps CNC in my book....... and yet there is something so aesthetically and visually pleasing about a set of CNC cups, like Auke's stainless steel cups for example.

Truth is, there are so many variables when it comes to cups. If you want a particular set primarily as a collectible, the feel of the cups is obviously less important than if you're going to be handling them/performimg with them regularly.

Cup size is a big factor when you're looking for a set to perform with (size relative to the size of your hands)....... size again relative to the type of loads you want to produce.......size yet again depending on whether you'll be doing close-up for a few, or performing on stage for many more to see.

When all is said and done, though, there are no rules other than picking cups that works best for YOU, based on what YOU want them for.

Fortasse

A lot of people think that CNC is better because the work is easier on the operator. That's not completely true. It takes less time to machine a single cup than to turn it, but the polishing stage is still done by hand.

CNC is also a rather wasteful process. Generally, you start with a solid block of metal, and the machine cuts away all that you don't need. This is one reason you don't see many sets of sterling silver CNC cups.

Depends on what you are cutting on the CNC machine. Copper has to be done very very slowly on CNC and is a dangerous process as you manually have to make sure the fall out copper is removed completely as the milling bits cut. Delrin is the same way. Last quote I saw for 110 machinable copper 1 linear foot was 792.00, the waste factor in most cases does not go below 79% of the stock material.

There are a lot of additional costs for making CNC cups vs. handspun. Just to name a few are custom jaws, milling bits and collets, all of which can be job specific and very expensive. All this adds to the cost of the final product.

The current machine shop rate ranges from 75-125 per hour shop time plus materials. This is one reason we won't make anymore Delrin cups or CNC cups period.

There are other CNC methods, spinning, vertical punch even hydroforming, again all high cost factors. The one nice thing about hydroforming, no tooling marks to polish out

...and I have no regrets about all those purchases, none whatsoever. Variety is the spice my magic needs.

G

That makes those copper Johnson cups a much better bargain!

Bill, indeed it does, I can't imagine what the blocks cost for those cups today. Not to mention the the time to make them. The outside milling is a breeze, it's the boring of the interior. I'm still somewhat amazed at what Johnson can offer thier brass cups for in relation to the size of the cup vs. the amount of machinable brass they need.

The Copper JPs are treasures in my collection. A lot of dedicated machining went into those and the price on those too at the time of sale were a steal.

If we don't get a handle on inflation soon, $300 sets of cups will be a thing of the past.

***the waste factor in most cases does not go below 79% of the stock material.***

It breaks my heart to see all that waste when turning wood cups so seeing 79% of expensive metal hitting the floor might do me in!

Out of curiousity, what will a Johnson cup take as a final load. A billiard ball? A lacrosse ball?

Lacrosse ball.

Yes it will by the skin of its teeth.

Be very careful when sizing lacrosse balls for Johnson cups, if they are just a smidge too big then they can get lodged inside the cup and won't come out easily or worse get stuck tight inside.

When I looked up the regulation size of a lacrosse ball, I was surprised at the large acceptable range. Maybe it's not that different to other sports (I've never looked up other sizes of balls)??

--
Lyn

It's possible to cut down on the waste significantly when CNC'ing any part. They do they by creating a casting of the part that is close to the final size and then use CNC to machine it to the desired size and finish. This is how all of the parts in your car's engine are made. They're cast and then machined only where needed.

I don't know if Johnson is actually doing this or not. I don't know the costs involved and maybe it would cost more to do the castings in limited quantity than the money that is lost in the extra machining time and material waste. And the waste isn't totally wasted but can be sold as scrap.

-Brian