Author Topic: Simple Dividing Head  (Read 19561 times)

Offline swilliams

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Re: Simple Dividing Head
« Reply #30 on: November 07, 2013, 01:23:17 PM »
Ok here's some shots which show what's going on with my leadscrew



above is the gearbox! the vacant hole is what the leadscrew goes through and the offending face can be seen. The one surface is shared with the mating gear meaning the outside diameter of the gear can touch the face around the point it mates with the other gear.



so this is the face of the gear. There's the odd bur and nastiness on the face of the gear teeth that goes against the gearbox casting. That's the source of my problems. I'll mount the gear in the lathe, cut the diameter that is contact with the face down smaller and reface it. More on that later.



These are the locknuts that hold that gear on the leadscrew. They have the odd dag as well, which can't help. I've cleaned them up with a file and deburring tool.

Anyways I pulled the apron off while I had the leadscrew out



I've had this lathe for 26 years and never pulled the apron off, so was expecting alot of crap to be in there. It wasn't so bad.



Anyway I cleaned the apron up. It's all good on that front now.

Then finally another detour



while I've got things apart I decided I should machine the back of the saddle so that I can use this taper attachment that I've got.

That's it for now

Steve

Offline Don1966

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Re: Simple Dividing Head
« Reply #31 on: November 07, 2013, 11:17:15 PM »
Ah! That's what I wanted to see. Doesn't look to bad Steve.


Don

Offline swilliams

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Re: Simple Dividing Head
« Reply #32 on: November 07, 2013, 11:31:33 PM »
Hi Don

Yep, I'm hopeful that it will come good without hassle

Steve

Online steamer

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Re: Simple Dividing Head
« Reply #33 on: November 08, 2013, 12:33:20 AM »
Did you get the rebuild kit Steve?

Dave
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Offline swilliams

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Re: Simple Dividing Head
« Reply #34 on: November 08, 2013, 05:50:58 AM »
Na no rebuild kit Dave. Now that you mention it I should buy one to have for next time, so thanks for making me think of that. The pin from the key in the worm has been peened over and I'll have to file it out to get that apart. Overall things were pretty good, so I'm happy to put it back together.

Steve

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Re: Simple Dividing Head
« Reply #35 on: November 08, 2013, 09:56:53 AM »
That pin came out with the key on mine.

Get the rebuild kit with the book...it's worth it!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline swilliams

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Re: Simple Dividing Head
« Reply #36 on: November 09, 2013, 12:13:43 AM »
Yep mine is the same Dave. It's just the pin is mushroomed over a little on the outside, so it doesn't want to come out. Anyway I'm happy with how the apron is.

Got the book, I just need to get the rebuild kit. I'll get onto it.

Steve

Offline swilliams

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Re: Simple Dividing Head
« Reply #37 on: November 09, 2013, 12:29:35 AM »
Once in a blue moon it actually pays to have a horizontal milling machine and there appears to be a blue moon.





My saddle is sitting on the mill table on a couple of bits of 1/2" round.



There is a slot milled for a key that aligns the taper attachment and a couple of holes drilled and tapped.



So the saddle is all finished off. Now to fix the thrust face and put it all back together. That is the task I've set myself for today.

Steve

Offline Don1966

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Re: Simple Dividing Head
« Reply #38 on: November 09, 2013, 01:24:13 AM »
Cool Steve, I like your taper attachment. Your bed ways look like that have just been scraped. Have you had it resurfaced lately?

Don

Offline swilliams

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Re: Simple Dividing Head
« Reply #39 on: November 09, 2013, 01:33:35 AM »
Hi Don

The bed was scraped by the guy I bought it off. He was an old retired machine tool reconditioner. I guess things wear pretty slow when you keep it oiled and don't have abrasive grit on the bed. Either that or I just haven't used it enough  :Lol:

Steve
« Last Edit: November 09, 2013, 06:50:19 AM by swilliams »

Offline swilliams

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Re: Simple Dividing Head
« Reply #40 on: November 09, 2013, 10:45:58 PM »
Got my lathe back together. Gonna do a test today and see if I can fix up an adapter I made to screw chucks onto my rotary table. Will report back later

Steve

Offline swilliams

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Re: Simple Dividing Head
« Reply #41 on: November 11, 2013, 11:35:45 AM »
Well I did my test and things are certainly a lot better. Could still be improved. I think I made the thrust on the leadscrew a bit too tight. Anyway I'll leave it for the time being, it may loosen up a little.

Back onto the dividing head



This plate will bolt onto the main body of the dividing head and hold the indexing plunger. I've screwcut a 5/8" x 24TPI thread to screw the plunger into. Next I'll attempt to make the plunger.

Cheers
Steve

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Re: Simple Dividing Head
« Reply #42 on: November 11, 2013, 11:39:28 AM »
Glad you got it all back together!....setting the clearance on those lead-screw bearings is really tough.  I still wonder if I set mine right!

Dave
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Damned ijjit!

Offline swilliams

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Re: Simple Dividing Head
« Reply #43 on: November 11, 2013, 11:51:31 AM »
Thanks Dave

Yes it's a PITA. I think you want it to turn nice and free. If it's a little tight and is tighter in one spot then there will be a periodic stress which equals an error. Lot of gears and shafts for a small fluctuation in torque to lead to a small error; kinda like dragging a block over a surface with varying friction using a piece of elastic. If you drag the elastic at constant speed, the block won't move at constant speed. At least that's how I'm thinking.

Cheers
Steve

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Re: Simple Dividing Head
« Reply #44 on: November 11, 2013, 11:58:02 AM »
I hear ya.

Connolly states the free motion of that thrust bearing is supposed to be .0003"....except I don't think this design is remotely capable of that level of adjustment....so ....you do the best you can....considering there are MILLIONS of these lathes out in the wild....I guess it works right?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!