Author Topic: Building a New Lathe  (Read 86090 times)

Offline DavidA

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Re: Building a New Lathe
« Reply #50 on: March 14, 2015, 11:41:29 AM »
The series by Dan Gelbart is very impressive.  But do we need that precision ?

I watched the series and after that the 0.0005" run out on my red lathe's spindle seemed horrific.
And his lab/workshop must have a crew dedicated to keeping it clean.

Guess I'll just have to tighten the headstock split taper bearing up a little more and hope for the best.

Dave. :(

Offline vtsteam

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Re: Building a New Lathe
« Reply #51 on: March 14, 2015, 12:05:59 PM »
I do admire it though -- a great series and very cool lathe. Appropriate for some (though probably not all) of the prototype work he does. I know personally I wouldn't want to worry about temperature differentials (or I guess even dust particles) to the extent necessary to hold tolerances at the micron level. Especially not on something like a Pipe and Bolt engine. Or listen to air bearings and my painfully loud compressor every time I had to turn anything. Well, I'm sure his compressor is better than my thumper!  :)

Anyway, back to this dog's ladder......turned out I didn't own a 1/2" -13 tap yesterday -- too late to drive to town. Couldn't believe I didn't so spent at least an hour searching multiple locations, but nope, I guess not. So nothing to show. I played with the Ebay DC Motor and controller instead. Picked up a tap in town this morning, so on with the show.
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 #52 on: March 15, 2015, 09:56:00 PM »
Milling:



« Last Edit: July 11, 2017, 04:19:52 PM by vtsteam »
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 #53 on: March 15, 2015, 09:57:29 PM »
Scraping:

« Last Edit: July 11, 2017, 04:20:26 PM by vtsteam »
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline Brass_Machine

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Re: Building a New Lathe
« Reply #54 on: March 15, 2015, 10:28:27 PM »
Nice! I need to learn to scrape...
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline vtsteam

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Re: Building a New Lathe
« Reply #55 on: March 15, 2015, 10:44:23 PM »
Heh, Eric here it is in a nutshell:

1.) Grab old tube of spot blue (or artist's Prussian blue oil paint).
2.) Squeeze tube to apply to rag. Tube cracks to allow getting all over hands, workbench, clothing, and eventually, face.
3.) Apply either to work (some people) or to flat surface (others) and rub work against flat surface to remove paint (some people) or add paint (other people).
4.) Scrape off spots with scraper. Either homemade or store bought. (Sharpen square).
5.) Squeeze more paint on rag if needed and apply to hands and face. Also work or flat surface
6.) Rub together. Scrape off spots
7.) Continue steps above for eternity. Or untll surface is as even as your aching back burning eyes, cramped fingers and paint covered safety glasses will allow. However, if you quit before 3 days and nights are up yer a wimp!
8.) Done
 :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:

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

Offline Brass_Machine

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Re: Building a New Lathe
« Reply #56 on: March 15, 2015, 10:49:43 PM »
Thanks Steve!

When I start building the new CNC mill I plan on getting it as accurate and as square as I can. Which means it will be a trapazoid and leaning!  :lol: :lol: :lol: :lol: :lol: :lol: :lol:

Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline vtsteam

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Re: Building a New Lathe
« Reply #57 on: March 15, 2015, 10:53:14 PM »
These guys didn't make it past step 2....you don't use a hammer! Big project though..... :)

<a href="http://www.youtube.com/watch?v=k95pB0jr5Cc" target="_blank">http://www.youtube.com/watch?v=k95pB0jr5Cc</a>
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline RussellT

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Re: Building a New Lathe
« Reply #58 on: March 16, 2015, 04:54:37 AM »
Hi Steve

It's a bit late now but I was looking at those square sections and visualising them turned through 45 degrees.  I thought that might make the sides more rigid as it would make the vertical footprint of the tubes higher - and it would mean that swarf would sit on them so easily.  Of course it would make them less effective as a ladder.

Of course that might be completely irrelevant as you may have something else to go on top.

Russell


Offline vtsteam

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Re: Building a New Lathe
« Reply #59 on: March 16, 2015, 09:01:06 AM »
Hi Russell, yes there are ways to be added to the bed. I'm waiting for the steel to arrive. Making cross members larger or more numerous also works to increase stiffness at few dollars difference, but I judge things are what I want this way.
I pulled one out actually after trying.  :beer:
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline RobWilson

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Re: Building a New Lathe
« Reply #60 on: March 16, 2015, 11:00:49 AM »
Go on Steve , nowt like a good lathe build  :thumbup:   



Rob  :wave:

Offline Will_D

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Re: Building a New Lathe
« Reply #61 on: March 16, 2015, 05:08:39 PM »
Always confuses me:

When you scrape do you scrape the white bits or the blue bits.

Re. blue going everywhere:

My old tube of blue was manky, 30 years old and more holes than a sieve.
So, in next tooling order popped on a tube of blue. New tube, clean fingers!  :beer:

WRONG WRONG WRONG.
They squeezed the order into a too small box and guess what suffered?

Not the expensive steels tools in their plastic boxes!

Oh No! It was the tube of blue on top of said hard robust plastic steel bits.

It managed to unravel the tripel fold at the end of the tube :Doh:

So now I haqve a BIG MANKY tube of blue!

Note to newbies: Buy the blue in the tin not the tube.
The tube may be bigger but you will be 300 years old when it runs out
Engineer and Chemist to the NHC.ie
http://www.nationalhomebrewclub.ie/forum/

Offline vtsteam

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Re: Building a New Lathe
« Reply #62 on: March 16, 2015, 05:18:11 PM »
Well it kinda depends Will. If your part is blued, then you scrape the lighter bits. If the reference surface is blued you sort of scrape the blue bits, but it depends because it can also get into hollows behind the high spots so that way is cruder, and you have to think -- but if working down a general area early on, it's okay.

First way is more definite. But I ran into the problem of the blue not rubbing off at all because my reference straight edge was so slick and the pressure so light it didnt remove the high spot blue on the part.

So to start I went the other way, but switched back when I hauled my cast iron surface plate into the tiny shop heaved  it onto the bench. Then I could get enough pressure and the plate was just a little bit rougher. All around better than the straight edge. So, am bluing the part, as normal -- or normal for me........

Second day of scraping.....
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline awemawson

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Re: Building a New Lathe
« Reply #63 on: March 16, 2015, 06:03:43 PM »
Steve, after the welding have you normalised the assembly, heat cycle or whatever. If not is it not going to carry on moving for weeks?
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Building a New Lathe
« Reply #64 on: March 16, 2015, 09:26:18 PM »
Andrew, it is a bolted structure, not a full welded structure. the few small welds are there to prevent crossmember shifting and they were laid down in a careful sequence, with cooling betwween each, and were peened. I don't guarantee it won't move, but I think it won't (within the tolerances that are acceptable to me). If it does, I'll have more scraping to do down the road. I chose hot rolled instead of cold rolled to further minimize warpage from milling and scraping.
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 #65 on: March 16, 2015, 09:33:39 PM »
Rob!  :beer: :beer: :beer: :beer:
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 #66 on: March 17, 2015, 11:39:51 PM »
Still scraping. I did take a look at some Youtube scraping videos this evening to keep inspired. Things have changed since I built the Gingery lathe! There were no instructions on scraping at all on the internet in 2002, and I just followed Dave Gingery's book. Now there are a great variety of videos and many different tools illustrated, techniques, etc. That's helped quite a bit tonight actually, though I'm still not done with the bed after 3 days. Anyway, my instructions above were largely tongue in cheek, but if anyone really wants to know how to do it, there's a lot of good video instruction online and a variety of methods to choose from :beer:
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline Fergus OMore

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Re: Building a New Lathe
« Reply #67 on: March 18, 2015, 04:18:07 AM »
With increasing old age and infirmary(?), I gave up and for 250 ( I think) I got the bed of a Myford Super7B slideways ground and the very worn saddle built up with Turcite. It still leaves a fair amount to do. However, several points about my earlier efforts might be pertinent.

The first-after machining, is a map of the job. The second is a scraping cycle. Probably third is to watch the obvious high spots- ruthlessly removing anything blued ( regardless of great accidents of excess blue). In other words, you should have blue   areas ALL along the job. You might have several cycles  to get there. Imagine little islands showing -when the tide goes out and as the tide recedes( ie scrapings) more islands pop up. With that done, it is time to break the islands into smaller pieces by knocking the tops of the mountains off. You are then getting this dots per square inch thing. The next cycle will expose a new island amonst the ones that you had seen earlier. Again, it is progressively time to work done the job all the way.

I think that it worth a couple of mentions. The first is the constant re-honing of scrapers using diamond paste and the other is to lighly stone the work to remove the burrs from the scraper's cutting action.

Anyway, that was my experience- for what it is worth.                                                                                                                                                                                                                         As a postscript( memory returning), I have a pair of rubber rollers which probably came from an artist's stencil set up. Two diffrent sizes and to use an ink pad. Whether or not, it helps is not known.

Again, it is not mandatory to use 'blue' I have a tube of oil based Burnt Sienns artists paint as well as the 'Engineer's Blue' This might help those who don't quite pass the Ishihara colour test!

Norman                                                                                                                   
« Last Edit: March 18, 2015, 07:45:39 AM by Fergus OMore »

Offline vtsteam

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Re: Building a New Lathe
« Reply #68 on: March 18, 2015, 10:58:10 AM »
Fergus, I've been stoning between passes, and the engineers or "spot" blue I have (from 12 years ago) is running out. It has the mandatory crack in the side of the tube in order to squirt blue out onto the hand that feeds it! Well I'm smart enough by now to wear gloves for this. I have a brayer (rubber roller) -- was once an artist, and used to oil paints and inks (though they have better tubes -- usually tin, not aluminum). I have Prussiaan Blue oil paint if I run out-- though it isn't as strongly pigmentd as the "real" stuff. But usable. I don't have a carbide scraper, -- HSS. But for the amount of scraping I will do in a lifetime, the purchase isn't warranted. For the scraper I sharpen frequently with a Japanese water stone. This puts a very fine edge on it.

The hard part is scraping a 3/4" wide by 26" surface and getting clean edge entry and end, and getting enough elbow room and foot space in a tiny shop for a position to do a proper cross hatch. I'm not ambidexterous. This is forcing me to be sometimes. But we're getting there. I predict it will be finished tonight.

This is not the bearing surface, btw. The ways will be added on top of this. And that will be scraped, too. I just want it to have a good start.  :beer:
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline Fergus OMore

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Re: Building a New Lathe
« Reply #69 on: March 18, 2015, 12:04:06 PM »

A 'Brayer'- well, I never! I'd got to things like 'Picker Buffers' from a very old firm that I had an association- for the spinning and weaving industry.
My carbide scraper is no more than a big piece of scrap  carbide insert tooling which is clamped to a traditional long ms shank. Happily, I have a decent diamond or two on a 100 T&C grinder and an undrilled faceplate on the lathe with diamond pastes( ex Vertex BSO dividing head)
Nothing more exotic.

So I'm following your your exploits with interest- and see an old man in a brown lab coat with completely black sleeves from iron dust and peering through a pair of Newcastle Brown Ale bottom specs and sweeping all the dustings away with both arms. :ddb:

I'm sort of dreading scraping the green mould off my villa in Spain- I feel for your pain!

Regards

Norman


Offline vtsteam

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Re: Building a New Lathe
« Reply #70 on: March 18, 2015, 10:54:21 PM »
Green mold off a villa...... sounds good! Nothing green here yet, except envy of Spanish villas.

I didn't make my prediction tonght, still more scraping to do, almost there. Tomorrow morning for sure..... knock on wood. Boy this makes me want to work in wood. I think patternmaking is going to be the immediately following prescribed relief from this.

I probably could have cut 2 days out by really scraping with a vengance at first instead of fiddling with high spots after the first cut. I forgot what it was like a dozen years ago. You don't need to baby it, and hitting spots is only for the endgame. Now I remember again -- I used to get pretty rough with it, once I learned the hard way that you can either spend a week, or a day on a carriage slide, depending on your uhhhhh panache.

Tomorrow for sure....... :whip:
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline awemawson

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Re: Building a New Lathe
« Reply #71 on: March 19, 2015, 03:27:20 AM »
Steve, how does steel scrape? I'd imagine it's quite a different proposition to cast iron.
Andrew Mawson
East Sussex

Online dawesy

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Re: Building a New Lathe
« Reply #72 on: March 19, 2015, 04:53:14 AM »
I envy you (sort of) the bed of the Churchill needs doing really but I'm not sure where I'd find a 6' straight edge to do it. Also how would one go about the 'V' sections?
Think a reground might be better in my case
Good work on yours though. I guess it's one of those jobs you don't rush.
Lee.
wishing my workshop was larger :(

Offline vtsteam

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Re: Building a New Lathe
« Reply #73 on: March 19, 2015, 08:42:43 AM »
Andrew, I plead ignorance -- I've only ever scraped steel and aluminum. All the ways and slides on the Gingery are steel.

In my imagination cast iron scrapes as nicely as it machines -- happily if grey, and past the skin. But I dunno for real.

Cast aluminum needs a low angle and can take longer than you expect, even though soft. It can chatter and dig.

Dawesy, I don't know how they scrape long beds and prismatic ways (I think that's what they're called) but there's probably a video or web page devoted to it somewhere now. I have the opposite problem -- a 4 foot straight edge in a 6 foot by 8 foot shop, and a 2 foot lathe. :)

Actually, I've switched to a 2 foot cast iron surface plate which is better all around, for this bed -- it does 2 rails at a time, and shows twist without checking with machinist level, etc. I just hope the plate is true -- I bought it at auction and it looks venerable in age. Ive tried switching the bed around to different orientations, and the marking seems consistent. But that isn't an absolute guarantee. I thought of testing the straightedge and plate against eachother, but things are too cramped to be able to do that now.

A 6 foot straightedge must be quite a massive object..... how did they do 10 foot lathes? 20 ft lathes? There must be a way, with shorter reference surfaces.

ps.....didn't someone here cut down a straight edge awhile back? And scrape a whole kit of reference tools......that cut would take a lot of courage.....
I love it when a Plan B comes together!
Steve
www.sredmond.com

Online dawesy

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Re: Building a New Lathe
« Reply #74 on: March 19, 2015, 09:29:33 AM »
The bed weighs about 200-300kg so a surface plate is out
I suppose there must be a way but my be has wear in the centre so I'd imagine id need to do the whole thing to get it flat and accurate. Prismatic ways sounds better than 'pointy edges '
Lee.
wishing my workshop was larger :(