Author Topic: Taper attachment build  (Read 694 times)

Offline WeldingRod

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Taper attachment build
« on: August 12, 2018, 11:18:57 PM »
As I've mentioned before, I have an exotic Hardinge: a TL10.  As you might expect, Hardinge taper attachments are pretty rare and pricey.  The one that fits the TL10 well, I think I've seen one...
The reason this project exists at all is that Ken (shaylocomotives-at the domain of-charter.net)  has castings for the way and the slide ($50) to match the Hardinge design (which is available on the Hardinge Lathe group).  The base casting is much more complicated and runs $125.
True to form, I started with measurements and 3D models (since I wasn't totally sure where all the bits were really supposed to be).  And, of course, I might have put a non-stock digital read out on the top edge of the mounting surface for the taper attachment https://madmodder.net/Smileys/default/doh-45.gif  It took a few tries to get the dimensions right, but it resulted in a functional taper.  Not very precise, of course...

Offline WeldingRod

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Re: Taper attachment build
« Reply #1 on: August 12, 2018, 11:22:42 PM »
Initial fit up of the plasma cut parts!  You might note the notch on the center plate to line it up.
Second photo is the mounting surface for the taper slide.
Then, copious welding!

Offline WeldingRod

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Re: Taper attachment build
« Reply #2 on: August 12, 2018, 11:25:41 PM »
Aaand, a comparison with the Sketchup model; looks good!

Off to the mill!  I flatted the whole bottom (with a bit not cleaned up) to make subsequent work easier.

Flip and cut more.  Carbide end mills rock!  Oh, and if you don't have a ring lite on your mill, you really need one!

Offline WeldingRod

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Re: Taper attachment build
« Reply #3 on: August 12, 2018, 11:29:48 PM »
My Rockwell isn't super big, so I had to turn it around and indicate it in.  I used the end mill to clean the edges while it was in the first setup so I had a reference.

I had to do some rather fiddly measurement to get the end of the end mill to cut the top edge of the key I needed.

One side of the key done!

Offline WeldingRod

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Re: Taper attachment build
« Reply #4 on: August 12, 2018, 11:33:59 PM »
I relieved the center to make fit up a bit easier.

Installed on the lathe with the plastic bits on top.

Crud.  A little higher than planned.  At least those parts aren't made yet...

Offline WeldingRod

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Re: Taper attachment build
« Reply #5 on: August 12, 2018, 11:36:27 PM »
And, its time for cast iron!

And a fit test with the plastic slider.

Offline WeldingRod

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Re: Taper attachment build
« Reply #6 on: August 12, 2018, 11:39:44 PM »
I set it up so that it had three positions for one end of the way; shallow taper, and +- a steeper taper.

Offline WeldingRod

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Re: Taper attachment build
« Reply #7 on: August 12, 2018, 11:45:36 PM »
Getting a way to clamp and adjust the way was quite a trick.  I used a long nut plate to engage the two shoulder bolts; you can take one out and not have the nut plate fall down while you swap holes.

A super long 1/4-20 SHCS adjusts it side to side, working in a round brass nut.  That was the first product of the steady rest!

Offline WeldingRod

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Re: Taper attachment build
« Reply #8 on: August 12, 2018, 11:50:03 PM »
Sorry, no in-progress shots of the slider!

I did manage a photo of fitting the gib key, though.

And off to the first assembly!

The funny stuff on the back of the carriage is my lubrication system.  If there's interest, I have pictures of that too...  If you ever wanted to know what hides inside a Hardinge carriage.

Offline WeldingRod

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Re: Taper attachment build
« Reply #9 on: August 12, 2018, 11:57:17 PM »
Adding the maker slot for the indicator; mini-hacksaw to the rescue!

I did some careful CAD layout and quite a few tries to get the engraver to get it all right.  Yes, I was sneaky and put three scales on, one for each of the pivot positions.

Precision installation of the indicator after I set the system to zero taper.

Offline WeldingRod

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Re: Taper attachment build
« Reply #10 on: August 12, 2018, 11:58:35 PM »
And after all that, who can resist a proper builder's plate!

Offline S. Heslop

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Re: Taper attachment build
« Reply #11 on: August 13, 2018, 12:20:01 AM »
Nice work. The scale and plate are a really nice touch.

It's also interesting to see a rapid prototyper being used for rapid prototyping!

Offline vtsteam

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Re: Taper attachment build
« Reply #12 on: August 14, 2018, 08:24:24 AM »
Wow, what a great project! Nice work  :clap: :clap:


What will you use it for first? Any ideas?
I love it when a Plan B comes together!
Steve
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Offline WeldingRod

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Re: Taper attachment build
« Reply #13 on: August 14, 2018, 10:50:41 AM »
I still haven't cut anything yet...  project #1 is either cutting some 1" drills down to MT2 or making a hardinge nose taper for a balancing jig.

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Offline PekkaNF

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Re: Taper attachment build
« Reply #14 on: August 14, 2018, 01:10:49 PM »
Very nice! Did you got any play?

Where did that descrepancy crep in with the cross slide and taper attachment deck height?

I relieved the center to make fit up a bit easier.

Installed on the lathe with the plastic bits on top.

Crud.  A little higher than planned.  At least those parts aren't made yet...

My speciality is to add a part thickness with wrong sign....latest was to add 20 mm instead of subsract it and even put the part in wrong way, because it did not look right - and then welded it solid. :D

Pekka

Offline WeldingRod

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Re: Taper attachment build
« Reply #15 on: August 14, 2018, 02:37:32 PM »
Pekka,
The slide is adjustable to get close to zero play using a gib; it runs smoothly.  The way its set up, it is free to move up and down if the way isn't lined up with the lathe bed (though mine seems to be very well aligned with those keys).
I think my final height issue was due to the relatively low precision fit of the plastic parts, or a thickness mistake on a plastic part.  I really didn't bother working out where I messed up, just fixed it.

Offline Joules

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Re: Taper attachment build
« Reply #16 on: August 14, 2018, 03:22:08 PM »
Good use of the 3D printing.   Was it strong enough to try making a part ?
Just get doing and make swarf, you can decide what its going to be later.   :thumbup:

Offline PekkaNF

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Re: Taper attachment build
« Reply #17 on: August 14, 2018, 04:07:37 PM »
Pekka,
The slide is adjustable to get close to zero play using a gib; it runs smoothly.  The way its set up, it is free to move up and down if the way isn't lined up with the lathe bed (though mine seems to be very well aligned with those keys).
I think my final height issue was due to the relatively low precision fit of the plastic parts, or a thickness mistake on a plastic part.  I really didn't bother working out where I messed up, just fixed it.

Thank you, Ok. the gib is back of the guide. Looks all very nice.

I like your 3D printed proof of consept plastic parts. That is tempting consept.

Pekka

Offline WeldingRod

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Re: Taper attachment build
« Reply #18 on: August 14, 2018, 05:18:08 PM »
I didn't even try to run the lathe with the plastic parts!
I have, however, cut threads using 3D printed custom change gears!

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Offline ddmckee54

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Re: Taper attachment build
« Reply #19 on: August 15, 2018, 11:16:16 AM »
WeldingRod:

I've given up on trying to get 3D prints with an accurate height.  I saw a video where the math was explained, but what I got out of it was that unless your layer thickness exactly matches with the gearing and resolution of your steppers, there is no way that you can get an accurate height.  This is because the software always has to play games with the numbers.  You throw in micro-stepping the stepper motors and it gets even worse.  Mostly just my opinion, YMMV.

Don
Too many irons, not enough fire.

Offline rowbare

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Re: Taper attachment build
« Reply #20 on: August 15, 2018, 11:28:54 AM »
Nice job! How did you do the pivot? Is it a tapered pivot like the Hardinge?

bob

Offline WeldingRod

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Re: Taper attachment build
« Reply #21 on: August 15, 2018, 11:27:04 PM »
No, it's a shoulder bolt in a matching reamed hole.

On the subject of 3D printing heights, I've been happy with the results when I measured it.  Quantization errors shouldn't be cumulative (unless somebody blew it on the coding/math). Microstepping doesn't change the fundamental mm/turn, just electrically divides it.  Surface finish on the top layer adds uncertainty.
I could run out some test pieces...  knowing I run my printer on freakishly thick layers. ;-)

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Offline ddmckee54

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Re: Taper attachment build
« Reply #22 on: August 16, 2018, 12:46:03 PM »
WeldingRod:

I don't see how the slicing software can get a part height that will be consistently accurate.  It's going to get really close, but I don't see how the part height couldn't help but vary by up to +/- one half the layer thickness.  I guess it would depend on the slicing software you're using.  I have a Prusa I3 clone so I'm using Slic3r that's been optimized for the Prusa machines, I don't print enough to be able to justify shelling out a couple of hundred bucks for slicing software. 

Don
Too many irons, not enough fire.

Offline WeldingRod

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Re: Taper attachment build
« Reply #23 on: August 16, 2018, 09:32:29 PM »
Ah, right!  Unless your slicer is able to do partial height layers, you are going to get an integral number of them.  I haven't heard of partial height layers as an option anyway.  When your later height is small fraction as of a mm, it's not an issue relative to the xy accuracy.  When you do like me and use 0.6mm layers, you've got to be a bit more tolerant.
I'll see about some z axis tests tonight.

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