BUILDING THE HEMINGWAY SPHERICAL TURNING TOOL

[Don1966]

I had some time off today and decided to start the Spherical turning tool, that I had promised to do. So guys and gals we have a start on it. I started out by mading the arm, washer, and boss as these were just basic turning. However I did take some photos of the body and side arm being made since these are the most complicated parts to make. Enough of my chatter and on to the thread. 
I first started by draw filing the square body and then drilling the mounting holes for the side arm and the countersinks for the cap screws heads after squaring the two sided.
 
Next came the body which I mounted into the lathe with the four jaw chuck after faced it off on both sides then finished by draw filing all sides. While in the chuck I center drilled both ends just enough to be able to mount the body between centers. I then mounted the side arm into a quick change tool holder and squared it off to the body between centers. After which I clamps them together and removed from the lathe.

I then used my transfer punch to make out the holes. Mounted the body on the mill and used the wiggler to find the first punch mark. I drill all three holes to tapping size.

After drilling I mounted the body on to the Pillar Tool for tapping out the mounting holes and secured the side arm to it.

Ok! with that done it was back to the lathe and mounted to the quick change tool post to be bored between centers. It is important the these operation be done between centers for the tool to work properly. I started the first hole with a 17/64 drill bit and being careful to pull the drill in and out to remove the swarf, but even with all my efforts the bit broke inside the body.    So I flipped the body around and drill it with a bigger bit till it hit the broken bit. Dulled my bit of coarse, I then removed it and knocked the broken bit out with a punch.    After taking a deep breathe. 

I then progressed with bigger bits using the tail stock for support.

To get the final dimenision of .75 I used the boring bar.

The parts completed thus far. Oh! I also press the body bushing in also.

And the parts assembled and mounted to the tool post.

That is all for now and if I can sneek some more time in I will have more progress to report.
Thanks for looking.

Don

[Tennessee Whiskey]

Well, at least while you were fluffing off on the clock you got something done . Nice job Bro. I really like that pillar tool, you just keep tempting me with it. Now we have to have a brass ball for the handle on this one. Keep at it old pal.

Whiskey

[Jim K 324]

                Nice piece of work buddy this thread seems like I seen it before , I guess the

               bushings pressed in ok, now that the body that the bit broke in is finshed you can
               sleep well tonight.             
               
           

[steamer]

Looking good my Brother!

Dave

[cfellows]

Nice work, Don.  Looks similar to a design I built a number of years ago.  Still use it whenever the need comes up for spherical shape.

Chuck

[vcutajar]

You are going to have it finished in no time.

Vince

[Stuart]

Don

I have made one of these , but being me I altered the design a bit,

Instead of just putting a tongue on for locating in the tool holder I made a holder to fit the tool post but thin and bolted that on the body thus reducing overhang.

A point is that in a moment of madness I purchased a comersial one from Chronos call a Repton what a piece of junk chatter lots of metal sticking out from the chuck. The Hemmmingway one is 100% better
Stuart

[sco]

Don,

I've built one of these a while back and remember what a headache it was drilling the hole in the body.  Don't get why its so important its done in the lathe?

Anyway nice work,

Simon.

[awJCKDup]

Nice work Don. I also noticed that green tapping stand, any chance you have some pictures of it?

John

[Don1966]

Thanks Eric, Dave, Jim, Chuck, Stuart and Vince for looking and you kind comments.

Don

I've built one of these a while back and remember what a headache it was drilling the hole in the body.  Don't get why its so important its done in the lathe?

Anyway nice work,

Simon.

Simon not really sure but from reading what G.H.T. Said about it that in order for it to cut a round sphere the unit had to be built keeping it at center line. Thanks for looking.
Don

Nice work Don. I also noticed that green tapping stand, any chance you have some pictures of it?

John

John you can check out my thread here  http://www.modelenginemaker.com/index.php/topic,2004.15.html

Thanks Don

[krv3000]

well dun

[Don1966]

Thanks for looking KVR3000.

Today the wife had some where to go so it was off to the shop and get some work done, at least so I thought. I didn't get as much done as I wanted and things just started going wrong from the start. I started working on the head. These following photos will explain what happen.
I first started by squaring off the ends and trimming to length. Then drilling out the center .25 hole and the .25 hole and .5 counter sink  hole for the nut.

I followed that up with spotting the side holes that will secure the dovetail pieces.

All the holes were then drilled to tapping size and all went well.

Then I started tapping the hole on the Pillar Tool being careful using cutting oil, rocking the tap back a forth and at mid tap of the hole, I pulled the tap out and cleaned it. On the last hole the tap just snapped at about 3/4 into the hole. I didn't apply much pressure to it, it just snapped. I take it as a fractured tape.

This is a fuzzy photo of the broken tape, it's the top hole.


I really don't know what to do with it other then remake the part. I thought about drilling a hole next to it and try to knock it out, then drill a bigger hole and put a plug.
At that point I just called it a day as I was disgusted.
Thanks for looking and I have to think about it for a while before I resume work on it.

Don

[steamer]

Don,

That looks like aluminum....if it is, you could try the old Alum trick to dissolve the tap.

If it's steel, you could try using s carbide PC drill ( very stubby) or short flute endmill and try cutting it out.

Nothing to lose.

Dave

[Maryak]

Hi Don,

Another way with steel is to heat the whole thing to bright red (ambient light) and then bury it in lime, (part size + 1" all round), for 12 hours. This anneals the HSS tap and then it can be drilled out with normal HSS drills.

Good luck with the removal.

Best Regards
Bob

[krv3000]

hi don well their  is several ways to get the tap out one is to use a masonry drill bit you can by tap removing tools but i think in your case as the hole is drilled all the way threw just brake the tap up by hitting it with a dowel pin or Wat ever you can to brake it in to lil peaces and remove it that way