Author Topic: Building a New Lathe  (Read 178261 times)

Offline vtsteam

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Re: Building a New Lathe
« Reply #750 on: August 06, 2018, 10:52:27 PM »
I went through a repeat of the lathe threading routine on the Craftsman -- a lot easier with the lathe already set up, and the earlier experience under my belt. I was able to use the old tap, as well to do the final thread sizing. Since the tap is made of the same screw material I will be using, the clearance is very close, with almost no backlash.

It was also at about this time that I figured out that the slightly eccentric and relatively close relief bore was probably the cause of my earlier problems.

Of course since this insert wasn't in the ram, the tap couldn't jam. And the threading was easily accomplished.

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #751 on: August 06, 2018, 10:57:22 PM »
And finally a trial fit -- it does seem to be a slight interference fit. I didn't drive it home, because I want to clear out the relief bore -- no sense having the jack screw binding. I guess I'll have to make up a longer boring bar to do it. Might take a while because of springing, but at least this part of the process will be finished.

I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Building a New Lathe
« Reply #752 on: August 07, 2018, 02:00:57 AM »
Persistence pays off, well done Steve  :thumbup:

Andrew Mawson
East Sussex

Offline PekkaNF

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Re: Building a New Lathe
« Reply #753 on: August 07, 2018, 02:57:18 AM »
Good Job. Pretty confident that the insert works out better than the original plan!

Pekka

Offline Neubert1975

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Re: Building a New Lathe
« Reply #754 on: August 07, 2018, 07:34:36 AM »
Nice work, as always ;-)
Good to see that you managed to make it work  :thumbup: :beer:

And now i will go out i my HOT workshop and continue with project mill power feeder.

Offline vtsteam

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Re: Building a New Lathe
« Reply #755 on: August 08, 2018, 09:27:13 PM »
Thanks Andrew, Pekka, Neubert!  :beer: :beer: :beer:

I bored the recess wider, and it was definitely slow going with such a thin long bar, but it did cut, and after a trial fit with a piece of acme all-thread, there was enough clearance to press the insert home.

Next step was to start on the jack screw. I cut off a 6" length of Acme rod, chucked it in the 3 jaw, and began turning the threads off of a 2-1/2" section. That will be the part that passes trough the tailstock end cap, and will accept the handwheel.

I had the tailstock itself apart, so couldn't use it as a support center for turning off the threads. So I had to take light cuits.

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #756 on: August 08, 2018, 09:32:08 PM »
But I got there eventually, and it was nice to have the three tailstock ram pieces together and functional.



I still need to make up thrust bearings for the jack screw, and mill a groove along the ram to complete these components. But not today. :beer:
I love it when a Plan B comes together!
Steve
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Offline Neubert1975

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Re: Building a New Lathe
« Reply #757 on: November 05, 2018, 01:16:17 PM »
any progress on this nice project ?  :beer:

Offline nel2lar

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Re: Building a New Lathe
« Reply #758 on: November 24, 2018, 09:05:05 PM »
Steve
Checked in on your lathe build and as usual I am not let down. You have done an amazing job and you will enjoy it for years. I love all your documentation and it shows the true craftsman you are. Beautiful build.
Nelson

Offline vtsteam

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Re: Building a New Lathe
« Reply #759 on: November 01, 2020, 04:22:43 PM »
The tiny shop has languished for a long time while I worked on many other projects and chores over the last couple years. But longing once again to build engines, I've cleaned shop and moved the new lathe to where I can work on it again and got ready to finish the tailstock ram. It needs a slot, clamping cam pieces, thrust bearing, and handwheel. Slot was next on the agenda.

Things were eventually reasonable again after much mischief from mice, condensation and time. Unnecessary stored items were moved out, the floor swept. I oiled cleaned and lubricated the lathe ways, removed some surface rust from the 3 jaw chuck. Then I hooked up the lathe's DC motor controller, removing the XL timing belt from the headstock, and gave it a spin. Unfortunately the controller, a Cycletrol 150 (manual attached) had suffered, and though it spun the DC treadmill motor and responded to the potentiometer to increase speed, it didn't act right. I couldn't slow the motor very much -- minimum speed was too high, and it ran inconsistently, sending odd momentary pulsed jerks to the motor while running

I thought maybe the problem might be that the potentiometer had become noisy. I rewired with new wire, and soldered connections (I had used alligator clip jumpers for testing in the past) and tested the pot with an ohmeter. But it seemed okay, and nothing I did made a difference. BTW it always seemed odd that the only pot that worked was a 1 megohm resistance, when the manual called for 50K ohms, but that's the only way it worked in the past.

There are also three trim pots on the controller's circuit board one for min speed one for max speed, and one for max current. Adjustments to these three still did not solve the problems.

Since I was pretty much at the limit of my circuit solving capabilities here, the tailstock ram slotting has been put on hold.
I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #760 on: November 02, 2020, 10:27:50 PM »
I sent for a temporary AC to DC speed controller a few days ago when the Cycletrol 150 first started acting up. Temporary because it only handles a max of 4 amps at 90v DC output while the Cycletrol was spec'd at 10A. Nevertheless I figured I could get light use out of the smaller controller, while deciding what to do for a permanent replacement. The Ebay 4 amp "Samgold" controller was only $30 delivered from a US supplier. There were suitable larger controllers available for $60, but from China which might take a month or two to get here.

I got the Samgold controller this afternoon, hooked it up and was pleased to see it ran the lathe with the heavy faceplate and 5 inch chuck combo without cutting out. I haven't tried turning anything yet, but I did apply some hand pressure to the edge of the slow turning 8" faceplate, and didn't cause a cut out. The spindle does have a 5 to 1 reduction from the DC motor. I could probably double that ratio with a jackshaft, since the high speed range seems more than needed. Maybe the temporary controller is adequate with this treadmill motor.



I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline vtsteam

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Re: Building a New Lathe
« Reply #761 on: November 03, 2020, 04:30:49 PM »
I thought about slotting the tailstock ram on the lathe, but since it's round and needs to be milled end to end, set-up would have required making too many fixture pieces, etc. at this stage in the lathe's completion. It could have been done, but I decided the best and easiest way would be to use the old round column mill in the other shed. So I cleared that machine off, cleaned it up, and set the tailstock ram on Vee blocks. I chucked up (colleted?)a 2" x .125" 48 tooth disk mill in a slitting saw arbor to cut the slot.

I actually wanted a .150" finished slot so I did it in two passes. The Craftsman tailstock that I'm using normally uses .150 for some reason. I thought about just going .125" but decided in the end to make the ram parts interchangeable.

So .150" it was. Cutting the slot:

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #762 on: November 03, 2020, 04:33:19 PM »
And the finished ram:

I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline vintageandclassicrepairs

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Re: Building a New Lathe
« Reply #763 on: November 03, 2020, 05:37:46 PM »
Hi Steve,
Great to see you back at the lathe project  :clap:

John

Offline tom osselton

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Re: Building a New Lathe
« Reply #764 on: November 03, 2020, 06:15:39 PM »
I picked up the same controller for a project coming up.

Offline vtsteam

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Re: Building a New Lathe
« Reply #765 on: November 04, 2020, 09:13:40 AM »
Hi John, glad to get back to work on it here, too! I hope to do a lot more machine work and casting this winter, with several projects in mind.  :beer:

Hi Tom, I'm surprised at how well it works so far and how compact it is. My main question is, is it rated at 4 amps or 400 watts (various sellers) and is that a max permissible draw, or a continuous deliverable? And if it is 400 watts is that at full output only or at low speeds as well?

What will you use yours for?  :wave:
I love it when a Plan B comes together!
Steve
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Offline tom osselton

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Re: Building a New Lathe
« Reply #766 on: November 04, 2020, 05:43:01 PM »
I want to build a 2x72 belt sander and have a spare 90v motor from my Craftex 601 milling machine. I belive I read that with these controllers it is recommended that the speed knob is turned down for starting to reduce the strain on it.

Offline vtsteam

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Re: Building a New Lathe
« Reply #767 on: November 04, 2020, 10:53:08 PM »
Hi Tom, looking forward to seeing that project when you start.

 :proj:


My experience with this controller is, yes, with a high inertia load like my 8" steel faceplate plus 5" 3 jaw chuck you need to start with the speed dial all the way down, then hit the power switch, and slowly speed the motor up.

I did want to see what would happen otherwise, so I intentionally flipped the power switch ON with the dial already rotated to about 1/4 speed. As expected, the controller automatically cut off as a result of the momentary power surge. But surprisingly, a second later it again started the motor slowly, and then ramped up to the 1./4 speed setting. This happened automatically.
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline vtsteam

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Re: Building a New Lathe
« Reply #768 on: November 05, 2020, 11:51:57 AM »
I decided to cast a copy of my Craftsman Lathe's handwheel for the new lathe's tailstock. The original is a wheel and handle construction with the handle press fitted into the wheel. The wheel is diecast zinc alloy, and so is properly drafted all around for sand casting a copy.

I managed to remove the handle -- the press fit was light enough. To use these pieces as patterns, I closed all holes on the wheel with circles of packing tape, and I cut a long length of  plastic tubing to cover the short stub-end of the handle. This will add a machining allowance and extra stock length to grip in the lathe when turning down the stub diameter before parting off.

The modified handwheel patterns:

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #769 on: November 05, 2020, 05:31:30 PM »
A lot of prep for sand, furnace, tools, crucible etc. after 2 years of disuse in an open shed roof area, but I got it done before evening: dried out the furnace walls with gentle bake, added a fire clay and sand liner to my cast iron crucible, and baked it hard, along with the furnace walls. I conditioned the greensand with water and a lot of cutting. Finally started in molding.

I am definitely rusty on that subject, so I went slowly!  :scratch: This hand wheel required  both coping down and a false cope.

Here is what that looked like:

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #770 on: November 05, 2020, 05:40:53 PM »
Then I rammed up the drag, rolled the flask, and separated them. I pressed the handle in, added sprue and riser, Shook out the first cope, set it on the drag again, and rammed it full of sand. Then I pulled the sprue and riser pins, separated the flask again, rapped and pulled the patterns and added pouring basin and gates.

Here's the drag finished:

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #771 on: November 05, 2020, 05:46:18 PM »
I had a little tearout at the wheel hub in the cope -- no draft on the hub since it was machined and I noticed afterwards a small burr there. I'll have to clean the casting up by hand if everything else is okay.

Here's the second cope, finished:

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #772 on: November 05, 2020, 05:58:06 PM »
Took about 25 minutes to melt 3 pounds of brass, and by the time it was ready to pour it was almost dark. I piled some firebricks on top of the flask to weight it down, gave the pot a skim and poured. Spilled a little, maneuvering around the bricks, and the riser didn't fill completely, but there should be enough hot metal to (I hope) prevent shrink cavities. We'll see, later on this evening.....

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Building a New Lathe
« Reply #773 on: November 05, 2020, 06:38:14 PM »
Cold short. I can think of a bunch of reasons -- metal not hot enough, die-cast-style spokes are too thin, forgot to vent. I could also move the riser opposite the sprue, though the hub might then have problems.

I may just pad out those spokes, pour hotter, and vent. The finger handle is usable. We'll see. Tomorrow is another day.

I love it when a Plan B comes together!
Steve
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Offline tom osselton

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Re: Building a New Lathe
« Reply #774 on: November 05, 2020, 06:54:00 PM »
Maybe extend the sprue using a tin can to increase the pressure like myfordboy does and poke the vent holes Id think that would work.