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The 4H4 model that's infinitely adjustable from 1/4" to 1/2" would seem to be the Perfect Widget for cutting tenons. Set the diameter on the widget, set length/depth of travel on the tailstock (or however you guys do it), spin things up to 500 or so, and give it a shove.

If it was that slick & easy, though, pipemakers would already be using it, and they're not.

Chris? OKRed? What am I missing?


http://www.jtsmach.com/jtswebshop/MillingTools/M033.asp

I would be curious to see what Red has to say. It would be $200 well spent if it worked.

I think the time spent keeping the blades sharp would offset the functionality ... I've heard Barbi had something like that but cost doesn't offset production in my case.. And if your using delrin it's a complete waste of money

I think James covered it there. Keeping the blades sharp and set properly would be a tricky task and ebonite is quite abrasive so to get the mirror perfect cut would require regular resharpening. Factories use something very similar if not identical but whats the one thing we always notice on factory stems? Bad tenons and facing from dull tools.

Maintaining sharpness would be a problem with carbide-tipped blades? (presumably TC) Especially when individual output is a couple hundred pipes a year vs. factory levels of hundreds per day?

Presuming it does a good job consistency and finish-wise, it would be easy to estimate the time and material savings that a specialized tenon widget would have.

It may work well for a wood lathe.

With a metal lathe there is no need. $2.00 HSS cutting blank will do a better job.

Presuming it does a good job consistency and finish-wise, it would be easy to estimate the time and material savings that a specialized tenon widget would have.

I am familiar with hollow mills but I have no personal experience with them. George brings up a point in finish. Is the cutter blade geometry good for the materials we are working with? May be wonderful for various metals but not worth a flip for hard rubber or acrylic. Changing the geometry if needed would be difficult without the equipment the factory used.
"Adjustment by precision graduated dial". How precision? Are there click stops? If so, what does each click equate to in the diameter change? Half thou, five thou?
The price point seems about right for an American made tool of this type. All of the above questions could most likely be answered with a phone call. The big question is the finish left behind. I'm a bit skeptical on multi-blade cutters like this leaving the quality of finish we are looking for. All it takes is one blade to screw it all up.
So, anybody want to shell out and try one?

It seems to me that the thing would leave a smoother finish if two of the blades were removed. I assume it needs four to cut the metals it's designed for, but vulcanite & acrylic should pose no problems. Indeed, the cutter I use now only has one blade, and it works great.

I doubt the indexing has clicks/detents, or is even calibrated well. It's probably relative. Meaning measuring test cuts would be the only way to know exactly what a mark means. Once you've measured it, though, you're good to go.

I think Premal is right that such a widget is unnecessary for metal lathe users, but I can see it being the best thing since sliced bread (if it works well) for the wood lathe crowd who don't have the money, space, or etc. for a second stem-only lathe. Especially since Tim West's tenon turner is no longer available.

Carbide would hold it's edge better but still need sharpening eventually and carbide blanks of that size would be very pricey and even more difficult to sharpen effectively and accurately. Best way would be carbide inserts but as far as I am aware the only system to use carbide inserts that is sized correctly, you already use lol.

In my book delrin still wins the day

caskwith wrote: In my book delrin still wins the day

No stomach for making REAL tenons, I see.

PS -- Different subject. I heard Paul Hubbart messed up his hand and is no longer making pipes. Is that true?

I can still make a real tenon, been doing quite a few recently actually.
I still prefer delrin though.

Regarding Paul, he hurt his hand quite badly last year and it put him out of the shop for several months. Just as it was healing he was offered a very good full time job at a local gun factory, in the area where he lives coming across full time work just minutes from your house is almost unheard of so he jumped at the opportunity. He is still making pipes but it has gone back to being a hobby time kind of deal. Saw him in april when James G came to visit and I am hoping to see him soon for an update and maybe a stich and bitch lol.

For anyone that cares to further explore this subject I would suggest you check the world of screw machine tooling.
For example:
http://www.brown-sharpe.com/4849.php
http://www.brown-sharpe.com/5253.php
At issue here is shank size (.625). A Erickson tailstock collet holder would be needed unless you have a huge lathe. Smaller shanks might be available in other brands. This type of tooling falls into the realm of what the old French production machines used.
I would not try to spin these tools in a drill press unless you have one of those 20 ton behemoths like George has (he had to reinforce his living room floor). Screw machine tools generally remain stationary in the turret and the work is spinning.
The hollow mills that started this thread are normally used to create bosses in castings. Another brand of these is Genesee. Here is a pretty good illustration of how these work (at least this brand): http://www.geneseemfg.com/products/holl ... -large.jpg

oklahoma red wrote:For anyone that cares to further explore this subject I would suggest you check the world of screw machine tooling.
For example:
http://www.brown-sharpe.com/4849.php
http://www.brown-sharpe.com/5253.php
At issue here is shank size (.625). A Erickson tailstock collet holder would be needed unless you have a huge lathe. Smaller shanks might be available in other brands. This type of tooling falls into the realm of what the old French production machines used.
I would not try to spin these tools in a drill press unless you have one of those 20 ton behemoths like George has (he had to reinforce his living room floor). Screw machine tools generally remain stationary in the turret and the work is spinning.
The hollow mills that started this thread are normally used to create bosses in castings. Another brand of these is Genesee. Here is a pretty good illustration of how these work (at least this brand): http://www.geneseemfg.com/products/holl ... -large.jpg

To elaborate on what Red sed: Actually, doing anything pipemaking-related on a drill press beyond Dunhill dot holes isn't recommended except with a large frame machine. The reason is because the "C"-shaped design of drill presses is inherently weak, and---contrary to what most people would guess---all steel/iron is equally rigid (+/- approximately 5% ). It sounds wrong, but it's true---the hardness, purity, and type of steel/iron used to make the frame of machine tools counts for almost nothing when it comes to flexibility. Only MASS matters. The only way to make a steel or iron-framed machine tool stiffer (and therefore more potentially precise) is to simply make it bigger.

To add insult to injury, the net result in marketing terms is to not bother even making small machines with tight tolerances, since the flex makes the additional work pointless. Meaning you get dicked both coming and going with a Home Depot or Lowe's $700 drill press. They are both flexible and loose.

All the above is true of any machine tool, including lathes btw, it's just that the design of drill presses magnifies the problem so is most easily seen there.

Just get a milling machine.

The Smoking Yeti wrote:Just get a milling machine.

Hell yes! But, I don't think George could get a Bridgeport thru his front door and into the living room. More braces.

The Smoking Yeti wrote:Just get a milling machine.

Believe it or not, they won't do everything needed in pipe repair work. Not anything under piano-sized and 10K lbs, anyway. There are too many clearance and space limitations.

The size milling machine needed to get a stem plus turning tools etc under the head would be pretty expensive. I would hazard that Georges DP is a better option for speed and for flexibility you should just get a lathe since a lathe is designed for long skinny objects as opposed to fat short objects for a milling machine.

George is also right about mass being a key component though to some extent design is important too, look at the casting on a cheap drill press/lathe and you will see very little in the way of struts and bracing.

For curiosity's sake, what would happen if someone were to grind the point off a Forstner bit, then try to drill it down the center to whatever size tenon you want? Would that work, or would there be problems with the bit wandering, or what?

You would find it almost impossible to do that, the forstner will be very hard and require a carbide drill to make the hole and carbide drills require the correct speed and an absolutely solid work setup. If the drill bit was allowed to wobble or the cutting surface was uneven then you wold just break the carbide drill, they are incredibly brittle.