Group Project: Dividing Head - The Build

[ErichKeane]

The answer is 40.

Maybe I should have went for 42, but no such luck. There are 40.

Ah, great! In my head the answer was '60', so I'm glad I asked!

 

[extropic]

The answer is 40.

Maybe I should have went for 42, but no such luck. There are 40.

Just curious. Since the conventional ratio for an indexer is 40:1, why would you want 42?

Or, was that dry humor?

 

[Shotgun]

Just curious. Since the conventional ratio for an indexer is 40:1, why would you want 42?

Or, was that dry humor?

Because, it is the answer to Life, the Universe and Everything.

Ever read "Hitchhiker's Guide to the Galaxy"? If not, do yourself a favor. . .

 

[extropic]

 

[Shotgun]

Busy, busy, busy this evening.

Good news: I got all the feature for the bottom of the first main base done.




Everything edge is properly broken and deburred. All the holes tapped. All told it took about 4 hours starting with the center hole drilled out. I did drill the lightening hole in the wrong place. Whups! I read the plans wrong. The others will be correct, because I made a drawing of what the DRO will read at the start of each metal removal operation. This one will be mine.

The next step will be to drill and tap the holes for the Auxiliary Base, and then bolt up a blank so that I can drill them together. This will be the setup for that operation.



I removed the compound slide, and sat the piece directly on the cross slide. I'll need to drill and tap that round puck that the compound slide attaches to. Then a bolt through a single bar from my clamp kit will be sufficient to hold it in place.

Now, @Flyinfool the measurement for the trunnion center is 3.486" up from the bottom. With this setup, it will come out at 3.595". I could slide a 100 thou something under the piece, but that seems like a way to introduce errors. If the trunnion moved up that much, would anyone ever know?


The bad news: I think I may have burned out the DC motor controller on my mill.

I was on the final pass of facing the bottom of the second base when she shut down on me. She quit earlier because the motor overheated. These treadmill motors have a thermal protection switch. Some people bypass them, but this is why I didn't. The switch cuts the AC going to the controller and shuts everything down. I put an ice pack on the motor to cool it and after a few minutes kept going, hoping to finish the operation.

The second time she quit, she sort of slowed down and then just stopped. The controller looked to be working. The signal generator that sets the speed, and the mill light that pulls power from the controller were still working. I'm thinking the MOSFETS overheated. With some luck, they'll work in the morning. If not, I'm going to be delayed while I tear down this other treadmill I've got in the shop.

(I was THIS close.)

 

[Ianagos]

I’d like to try to knock out these trunions this weekend. What diameter do I need to turn the bosses to?

I can probably hit it within half a thou. Better if the material isn’t too bad. What number should I be looking to hit?

 

[rwm]

Shotgun- great work! Sorry to hears about the controller demise. Hey, should we consider skipping the lightening hole to save time and tooling? I little heavier is not a big issue. Should we try to find someone on the forum to surface grind all the bases (bottoms)? That would be slick.
I have been working on the shift clamps. I will post pics.
Robert

 

[rwm]

The only issue is lots of tool changes. The part cannot be easily indexed if removed from the vice.



One more clamp to go.
I don't want to make any more shifter shafts until I see how this all goes together.

Robert

 

[Shotgun]

Shotgun- great work! Sorry to hears about the controller demise. Hey, should we consider skipping the lightening hole to save time and tooling? I little heavier is not a big issue. Should we try to find someone on the forum to surface grind all the bases (bottoms)? That would be slick.
I have been working on the shift clamps. I will post pics.
Robert

Good news. It wasn't the controller. Just the motor. I can either spend a few hours making an adapter using the one I have on the shelf (it's 1.75Hp, instead of 1.5Hp), or I can dig the one out of the mill I have taking up floor space. Either way, I'm not going to be down for long.

@Ianagos I'm aiming for the 2.7500 called out in the plans. With the hole saw cutting slightly undersize, and then finishing with the boring bar, I should be able to hit it repeatedly. Once I get the boring bar set, I won't be moving it, so every piece should be exactly the same.

@rwm, I bought a carbide hole saw for the lightening hole. It should go faster now. I think the hole is necessary for clearance of the spindle. If that is wrong, then I'm REAL good at NOT doing things.

I'd like to have mine ground. It could be pressed into service as an angle plate then. I made a narrow angle plate out of this material, grinding it on my mill. That was painful, and not nice to my mill.

BTW. . . tool changes? You should see the array that I used to get the bottom complete.

 

[ErichKeane]

Good news. It wasn't the controller. Just the motor. I can either spend a few hours making an adapter using the one I have on the shelf (it's 1.75Hp, instead of 1.5Hp), or I can dig the one out of the mill I have taking up floor space. Either way, I'm not going to be down for long.

@Ianagos I'm aiming for the 2.7500 called out in the plans. With the hole saw cutting slightly undersize, and then finishing with the boring bar, I should be able to hit it repeatedly. Once I get the boring bar set, I won't be moving it, so every piece should be exactly the same.

@rwm, I bought a carbide hole saw for the lightening hole. It should go faster now. I think the hole is necessary for clearance of the spindle. If that is wrong, then I'm REAL good at NOT doing things.

I'd like to have mine ground. It could be pressed into service as an angle plate then. I made a narrow angle plate out of this material, grinding it on my mill. That was painful, and not nice to my mill.

BTW. . . tool changes? You should see the array that I used to get the bottom complete.

I'm other side of the country, but I have an 6"x18" surface grinder if you wanted it ground. Shipping might be a bear though. Additionally/alternatively, I can do a shaper-finish I haven't got that down as well as ABOM, but I've got pretty good results so far.