Author Topic: Building a New Lathe (Read 509639 times)

vtsteam · « **Reply #175 on:** April 24, 2015, 08:51:13 PM »

Scraped in one direction:

vtsteam · « **Reply #176 on:** April 24, 2015, 08:56:05 PM »

Scraped back 90 degrees, before stoning off the burrs:

vtsteam · « **Reply #177 on:** April 24, 2015, 09:02:13 PM »

After quite a few more passes, progress. Most of the edge is getting blued. Only the far right is a bit shallow, and likely the next pass will show blue there,too:

S. Heslop · « **Reply #178 on:** April 24, 2015, 09:14:02 PM »

Hope I didn't miss something, but how are you measuring the taper? And how are you keeping it square to the top surface?

vtsteam · « **Reply #179 on:** April 24, 2015, 09:28:33 PM »

I measured the width of the way piece in this case, since the other edge is the reference and I want them to be parallel.

As far as keeping it square, I did that by hand and eye.

Of course there's a bit of a hedge in doing this. I removed a total of .004" in all of that scraping. The liklihood that I would be off by that much -- the max possible -- all to one side of a .375" width is nil.

Oh, also, the edge picked awhile back for the reference edge was the edge which, by measurement, was the most out of true. That one was trued up first, and then the others measured from that.

vtsteam · « **Reply #180 on:** April 29, 2015, 09:25:02 PM »

It's been tough to work indoors now that warmer weather has started -- so much to do around the yard and house. But I have been taking a little time each day to do at least some small job on the lathe.

Here is a pattern I just finished for the carriage casting:

Brass_Machine · « **Reply #181 on:** April 29, 2015, 10:48:44 PM »

Looks nice Steve. I am anxious to see you finish this guy...

vtsteam · « **Reply #182 on:** April 30, 2015, 09:24:22 PM »

Thanks Eric!

Might take awhile. It threatened to rain today, but I took a chance and did manage to get the part cast late in the afternoon. It's a somewhat tricky pattern with a parting line up a short way, and needing to be coped down in the center section, so I had to bed it in a false cope first.

Plus there's a greensand core that luckily held together. And it just barely fit in my larger flask. I had only a half inch to the edge at the riser. I was worried it would break through. The whole thing worked out first shot, so I'm happy. And it didn't rain! A few drops now in the evening. The raw casting....about 7 lbs:

Brass_Machine · « **Reply #183 on:** April 30, 2015, 09:41:01 PM »

That's it, I am going to VT this summer so I can see some casting done in person.

Looks nice!

vtsteam · « **Reply #184 on:** April 30, 2015, 10:13:20 PM »

Sure Eric! But I don't have much interesting high tech stuff.

That pattern was made of white pine scraps left over from building the bench. The casting was molded in plain sand mixed with fireclay (not even bentonite) -- ten years old, too. And melted in a plaster of Paris lined furnace, with a simple homemade half inch EMT tubing propane burner. And no blower. All this stuff detailed elsewhere on this forum in various places, so there's not going to be a whole lot new to show you!

Brass_Machine · « **Reply #185 on:** April 30, 2015, 10:46:53 PM »

As much as I like to learn... I always do best with seeing it in action. Still exciting to me.

awemawson · « **Reply #186 on:** May 01, 2015, 01:50:54 AM »

Very nice Steve, that's come out a treat

Meldonmech · « **Reply #187 on:** May 01, 2015, 03:15:36 AM »

Hi Steve
Nice sharp casting, looks great.

Cheers David

vtsteam · « **Reply #188 on:** May 01, 2015, 04:54:33 PM »

Thanks Eric, Andrew, David!

Machined the slides and cleaned up the top some to get ready for adding the carriage way:

RobWilson · « **Reply #189 on:** May 02, 2015, 04:08:18 AM »

Nice going Steve

Cracking looking casting , the lathe is starting to look like a lathe

Rob

awemawson · « **Reply #190 on:** May 02, 2015, 10:20:36 AM »

No, Steve told us early on in the project, "It's a ladder for the dog"

vtsteam · « **Reply #191 on:** May 02, 2015, 11:16:46 AM »

Oh, right....forgot! Poor Fletcher, I got carried away with the decorations. I'm just calling it a lathe -- because it sort of looks like one, not committing to anything. Just kinda putting pieces together to see if it might work that way, in case I do build a lathe some day.

Course, with all these geegaws on it now, I'm wondering how will I ever train him to climb up and paint the house?

Thank you kindly Rob! Might cast a decoration today sortof in the shape of an apron.

If I don't get roped into tilling the garden. Been hiding out in various locations until the family goes to town.....

Manxmodder · « **Reply #192 on:** May 02, 2015, 01:02:57 PM »

Great job, Steve,it's looking really good

. Fletcher won't be too down hearted just yet,with the carriage and lead screw installed he probably thinks you've gone the extra mile and built him a mechanical dog lift rather than a basic ladder. I get the feeling he's gonna feel cheated and disappointing at a later stage though.....OZ.

tom osselton · « **Reply #193 on:** May 02, 2015, 02:46:04 PM »

Looking good Steve!

vtsteam · « **Reply #194 on:** May 02, 2015, 03:04:47 PM »

Thanks Oz, Tom!

I got the apron cast, this time in aluminum since it doesn't have any sliding surfaces. I timed the melt -- it took 17 minutes from charging the furnace until i was pouring. Next time I'd like to weigh the propane tank before and after. I wonder how much propane I'm using? I don't think it's a lot through that small burner. and I'm running 7 psi at partial throttle.

PekkaNF · « **Reply #195 on:** May 02, 2015, 03:17:43 PM »

This might be noob-question, but Why is there so litlle meat on cross slide casting on front shear? Looks awfully little surface area on this picture?

Pekka

vtsteam · « **Reply #196 on:** May 02, 2015, 03:36:14 PM »

Pekka it's quite a bit of support in reality (pics don't show it as well) the shears are 9" long and made of zamak ZA-2, which is stronger than CI. There will be 1/4" 1" x 9" steel underneath. We're talking 9" x 7/8" total thickness along the way for the front shear.

Also under the 3" wide center section, you're looking at about an inch of upper section thickness bearing on the way.

By contrast the Gingery has 2-1/4" wide center section, and no support wings, and is cast in aluminum. So, 2-1/4" of support along the ways.

I just judged it was sufficient. And a heck of a lot more support that the Gingery, on what is basically the same size lathe. The rear shear was made thicker because it lacks width, but the front shear section is pretty wide so I didn't think it needed more support. Also I wanted to be able to tap and bolt nto the reaar shear -- that was already do-able in the front, past the sliding edge. There is 7 pounds of material in that casting, and I didn't want to pour more than I felt necessary with the crucible topped up as it was.

In other news.....here's the back of the apron in case anybody is interested. the points are from vents pushed up in the sand, and as you can see there isn't any shrink cavity, so should machine easily.

vtsteam · « **Reply #197 on:** May 02, 2015, 05:59:07 PM »

Here's how the steel retainer piece (foreground) goes on. I've clamped it temporarily to bottom of the carriage. It gets screwed in place. Likewise the cross slide (sitting in place behind) is a slab of cold rolled steel and will be screwed down when the time comes.

vtsteam · « **Reply #198 on:** May 06, 2015, 01:37:29 PM »

I've fit the slides under the carriage, the apron, the gib, the gib tightening screws, and the cross slide ways. The completed carriage now slides freely along the scraped ways without play in any direction.

philf · « **Reply #199 on:** May 06, 2015, 01:54:36 PM »

Steve,

Looking very nice I like the 'retro style' feet.

Has there been mention of the headstock? Is it to have plain bearings or ......?

Phil.

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Author Topic: Building a New Lathe (Read 509639 times)

RobWilson