Author Topic: Building a New Lathe  (Read 163765 times)

Offline vtsteam

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Re: Building a New Lathe
« Reply #150 on: April 03, 2015, 06:10:19 PM »
I tried the tailstock on it.

« Last Edit: July 11, 2017, 04:00:02 PM by vtsteam »
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Offline NormanV

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Re: Building a New Lathe
« Reply #151 on: April 03, 2015, 06:14:26 PM »
Will it be the same tomorrow? I only ask from the frustration I have experienced from earlier scraping jobs.

Offline vtsteam

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Re: Building a New Lathe
« Reply #152 on: April 03, 2015, 07:15:45 PM »
i don't know Norman, I can't predict the future! I certainly hope so. It was the same ths morning as it was last night......

Anyway, this evening I measured the thickness of the ways all around, inside and out along 5 stations and I wasn't able to measure a thickness variation -- my calipers are good to .001', so I can't tell any better than that. But i don't think I will need to do much if any scraping on the bottom of the ways. I'll know better when fitting the carriage. Maybe there will be a tight spot that needs a little work.

The closeness all over surprised me, because i knew i had taken more off in some areas than others. So I measured two cutoff pieces of the way stock -- They also measured the same all over. So it's pretty obvious that scraping really takes off a minute amount of material each pass. I probably did 20 passes and rubs and stonings over the last 2 days, thinking i did a lot. But not even a thousandth of an inch was removed.

Earlier today, I bought a 3/8" thick by 1-1/2" bar of hot rolled steel from Lester to make a narrow straightedge in case the underside needed scraping. A special straightedge would be the only way to check in there.

i also checked the widths of the ways gap and outside dimensions. The sides of the ways wll need some scraping as the tailstock is a tight fit at the ends. I knew the way stock was bowed very slightly when gluing up. It looks like about .004", worst case. That would be slow scraping on the top side, but should be faster on edge. I'll need to make the straightedge to start a reference edge on the ways.

« Last Edit: July 11, 2017, 04:00:43 PM by vtsteam »
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RobWilson

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Re: Building a New Lathe
« Reply #153 on: April 04, 2015, 04:26:04 AM »
 :bugeye: Now that lathe bed looks the mutts nuts Steve   :thumbup: , you must have the patience of a saint mate  :bow: :bow: :bow:



Rob

Offline Will_D

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Re: Building a New Lathe
« Reply #154 on: April 04, 2015, 05:33:06 AM »
Also some pre-rub orange stuff that he called "orange". No idea what those were, but it would be great to try an alternative to the Dykem Hi Spot and artist Prussian artist colors. I think they could be improved upon -- and probably are.
I also watched that video and was wonering about the orange pre-rub?
Anyone any ideas?

I use Stuarts Micrometer Engineers Marking blue
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Offline awemawson

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Re: Building a New Lathe
« Reply #155 on: April 04, 2015, 05:42:00 AM »
Looking excellent Steve.  :bow:

Have you contracted 'Scrapers Elbow' yet  :ddb:
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Offline bertie_bassett

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Re: Building a New Lathe
« Reply #156 on: April 04, 2015, 11:34:29 AM »
blimey you've put some hours into that, looks great for it though!
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Offline Manxmodder

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Re: Building a New Lathe
« Reply #157 on: April 04, 2015, 12:04:37 PM »
:bugeye: Now that lathe bed looks the mutts nuts Steve   :thumbup: , you must have the patience of a saint mate  :bow: :bow: :bow:



Rob

He's just showing off with that scraping caper,what's wrong with using a block of wood and a bit of coarse sandpaper  :) :)...OZ.
Helixes aren't always downward spirals,sometimes they're screwed up

RobWilson

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Re: Building a New Lathe
« Reply #158 on: April 04, 2015, 12:15:50 PM »
:bugeye: Now that lathe bed looks the mutts nuts Steve   :thumbup: , you must have the patience of a saint mate  :bow: :bow: :bow:



Rob

He's just showing off with that scraping caper,what's wrong with using a block of wood and a bit of coarse sandpaper  :) :)...OZ.


I would reach for the angle grinder OZ   :lol: :lol:     , Pete. sent me two carbide scrapers he had made himself , wow do they cut  :dremel:


Rob

Offline Fergus OMore

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Re: Building a New Lathe
« Reply #159 on: April 04, 2015, 12:48:28 PM »
Also some pre-rub orange stuff that he called "orange". No idea what those were, but it would be great to try an alternative to the Dykem Hi Spot and artist Prussian artist colors. I think they could be improved upon -- and probably are.
I also watched that video and was wonering about the orange pre-rub?
Anyone any ideas?



I suspect that this is something called 'Burnt Sienna' which is an artist's colour and is a mixture of bauxite and iron oxides.

I've still the remains of a tube somewhere along with cobalt blue. I couldn't get the normal 'red lead' locally and settled for going to an artist's shop. At some car boot sale, I came back with the equivalent of rubber pickabuffer rollers( ex the spinning industry) and then made here at Gateshead.

Originally, there was family 'interest' in machine tools locally. Both went 'bust' then I began to look for places where there was the 'remains' of tooling and finally just gave up.

Then I found a very abused Super 7B and was going to send the bed to Myfords in Nottingham for grinding. Then someone suggested 'Blue Diamond' in Shildon who had a slideways grinder. They dropped the price to compete with the Myford one( who went into liquidation) and Blue Diamond slideways ground the bed and Turcited the saddle back to height.

The cost- apart from my transport to and fro- was a mere 250. I did the easy bits and gear cut the new gears.

Then the snows and wind came. Whipped the roof off the workshop. Then I got real problems with my wife's medical problems.

Nice to read about something pleasant. Thanks, Steve.

Norman

Offline Manxmodder

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Re: Building a New Lathe
« Reply #160 on: April 04, 2015, 01:05:29 PM »
 Steve,you do realise that this machine could one day end up in be in a machinery museum collection somewhere.

So,maybe we need to give it a name now so those looking at it in future know some of it's history.

How does 'The Fletcher VT ladder lathe' sound ?  :)  Perhaps it should have a brass name plate attached with a Fletcher paw print included in the design.
Helixes aren't always downward spirals,sometimes they're screwed up

Offline vtsteam

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Re: Building a New Lathe
« Reply #161 on: April 04, 2015, 05:46:48 PM »
Holy cow, that's a lot of replies! Thanks boys, one and all!!! :beer:

I don't have scrapers elbow, but I do have the scraper's blues  :)

Angle grinder  :Doh: why didn't I think of that!!!!! (although, I do have to say that Bodger John's shaft finisher was pretty impressive.....)

Bertie, the time just flies when yer having fun! Some people go to the gym, I just lift a small lathe ways back and forth from the plate to the bench, and the bench to the plate, scraping a microscopic amount of metal off each time. A couple days of that, and shoveling snow seems like a nice break!

Norman, thanks buddy. I hope it does add something pleasant to read. Though it might get laughable yet because I haven't made the big screw up that is par for the course. My sig isn't there for nothing.

I don't know if it's raw sienna -- it looks kind of like a sort of wax in a tin, that "orange" -- pretty transparent for artists colors -- very pale orange. And it goes on before the rub -- I'll have to find that video and post a link so you can see it.

Sandpaper, Oz, well I'll tell ya........there's nothing wrong with filing during this stuff, even if you're scraping, as evidenced today.

Okay, so that brings me to today.  Remember I said I bought a piece of 3/8" x 1-1/2" x 27" hot rolled steel from Lester yesterday? Well today I painted some muriatic acid on it outside to take off the mill scale, but it was too cold work well, and it just did a partial job. I didn't have a container big enough to submerge it in either. So after a half hour of repainting it with the stuff and a large part of the scale gone, I rinsed it off and took it down to the big shop to mill one edge more or less flat, and brought it back to the tiny shop to scrape.

The idea was to make a small straightedge that I could use on the sides and bottoms of the ways to check and/or scrape them. I have a big 4' straightedge, but it's way too big!

So things were going swimmingly well -- it was nice to work with something light in weight, and that could be clamped in the vise. And sinc the edge was so narrow, it was really fast to scrape. But after getting ridof the initial hump in the middle and about 10 scrapes I wasn't making much progress. I tried scraping harder, but the blue just wouldn't move.

That's when I broke out the big heavy rasp and laid the scraper down. Ysee I finally remembered that 2 days work didn't even remove a thousandth of an inch (at least for me and my HSS scraper), so if there was 2 thousandths to remove........well I could do the math.

So, bottom line, don't feel committed to the scraper in moments like this, there's nothing wrong with filing the high part down if your blue isn't moving after some determined scrapes and trials.

I find that with a nice big file, no handle, laid flat on the work I can actually feel the high areas becaus the file has more bight there -- it sticks.

And a few minutes with the file really did the job. There was still scraping left to do. But not 4 days worth. I finished the straightedge this evening. It isn't pretty (yet).....but it's straight. It instantly let me find that the bend in the ways was really  mainly in one of the pieces, not both. So I started on the worst edge to turn it into a reference for the others. That way I can measure the variation and know where to scrape them to.

Again, I got only so far and then it slowed, so I broke out the file and went at it, removing several scraping days worth of material in a few minutes. By the end of the day I had my edge.

So that's the lesson fo the day. There's no shame in filing on a scrape job.

And also, don't put it off. Because if you go 10 scrapes and then file, you might as well have just done 1 scrape and then filed -- you're at the same point in the process either way. One might be a day quicker than the other!


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Steve
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Offline Fergus OMore

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Re: Building a New Lathe
« Reply #162 on: April 05, 2015, 03:44:13 AM »
Always difficult to do 'long distance learning'. My experience WAS that hss scrapers were too poor and time consuming.
I bought one from Greenwood Tools in the UK which had detachable solid carbide blades( a couple). One was honed to do as you are doing- flat work whilst the other was ground on a green grit into a hook and again, finished on a diamond wheel. Actually, the wheel came from a commercial spectacle frame supplier and was for shaping lens blanks. It had become worn and I got it cheaply. It's still o my Stent grinder.

Not content, I salvaged a hollow leg from a pair of long pruning cutters to hold a piece of scrap carbide insert.
Most carbides are too blunt in small lathes but the advent of 'diamond' pastes and cheap so called diamond wheels came in. There was a lot of ballyhoo about carbon( diamond) and steel but I have never had problems.

What there was/ and perhaps is, is a write up in the Home Shop Machinist and Machinist Workshhop  for General and my date is 22/11/2005. There are 3 pages, I still have 2! In the body of the comment is reference to Projects Book 4- which I haven't got. Quelle surprise-stand by your ropes and fenders- I've found FIVE pages- then it all got light headed.

Probably, there is the opportunity to make up aluminium disks to take the various grades of paste.

---------------------------------------------------------------------------------------------------------------------------

My odd thoughts are unhappy about the safety aspect of Connelly's advice on making up pigments.
Heaven knows what the Health and Safety People would make of it today. I recommended buying a couple of artists tubes but making it-Hell, No!
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Again, 'Bob' one of my old mentors used to use 'soda water' or so he said when he scraped. I'll leave it at that

----------------------------------------------------------------------------------------------------------------------------

Have to wipe up the snots at the perhaps end of a bout of nasty 'flu'
Waiting to take tests now


Norman


Offline vtsteam

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Re: Building a New Lathe
« Reply #163 on: April 05, 2015, 07:24:29 AM »
Well, Norman, I do appreciate that there are carbide and diamond for tools, but they hadn't yet descended upon the tiny shop from above, and a file, and old fashioned scraper and a bench stone were near to hand!

I remember once long ago in tidewater Virginia, we hopeful boatbuilder youngsters had a visit from an old master builder for a talk and instruction. One guy somewhat in awe, asked him what the best wood to use for framing was, in his opinion. "Why, white oak," he said. " Oh," said the apprentice, looking terribly unhappy, "I have a thousand board feet of oak I just bought. But it's red oak!"

"Well son, then that's the best wood to use for framing," said the old guy.



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

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Re: Building a New Lathe
« Reply #164 on: April 17, 2015, 11:12:24 PM »
A bit of a side excursion while I experimented with ideas for the electronic change gears, and I think I have enough of a proof of concept at this point. So I'm moving discussion here in this thread. It originally appeared in the "How Do I" forum under Elecronic Leadscrew thread.

As it stands now I have a FORTH program running on an Arduino board that will divide spindle encoder pulses and produce stepper movements to drive a leadscrew. And the ratios have been worked out to suit my intended leadscrew pitch, the encoder, and the stepper motor at inch thread pitches. I do need to test it at speed with the ordered encoder, but otherwise it seems do-able and everything works when breadboarded.

So back to the mechanical work on the lathe.
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Offline vtsteam

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Re: Building a New Lathe
« Reply #165 on: April 18, 2015, 06:55:08 PM »
I attached the new 600 line encoder to the toy motor and ran 375 rpm. The FORTH code handled the data rate fine all the way through 6TPI pitch - the coarsest I plan on. And likely requiring lower spindle speeds anyway, as it's usually found on larger diameter work.

However the stepper motor started to miss step at that spindle speed. Finer pitches worked fine.

It's a 20 year old used stepper. Not the motor that will go in the lathe. And I was only running 12 volts. I can run 24 v  and that will allow higher step rates.

So it does look like the high resolution encoder won't outrun the board. And the electronic leadscrew has a good chance of working out.
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Offline vtsteam

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Re: Building a New Lathe
« Reply #166 on: April 20, 2015, 05:00:42 PM »
Spent part of today scraping the edges of the bed ways . I finished the back outer edge and am using it now as a reference to scrape the front edge. After that is done, I'll work on the two inner edges.

Some things I learned long ago in woodworking are very useful while scraping an edge parallel with another. To correct a tapered board with a joiner, you drop the narrow end down onto the bed just past the cutter head, so a bit of uncut edge rests on the stationary table. This cuts progressively deeper at the wide end of the board. When parallel, you then take a full pass to remove the slight bump.

While scraping I realized that to bring an edge parallel to another edge you want to concentrate your scraping at the high spots closer to the wide end (if the high spots haven't fully reached either end). And leave the unscraped high area near the narrow end to support the straightedge. (Just like the stationary table on a joiner) .

Which seems anti-intuitive. The tendency is to want to scrape all the high spots off full length. The edge will then end up straight, but it will not be parallel, and you will eventually have to scrape to bring it in.

Instead, take off metal only near the wide end, and leave high spots near the narrow end untouched even though the narrow end hasn't been reached with marks. This will force the marking progressively down the wide end. Once the scraped portion is parallel by measurement, you can then continue to scrape evenly. all the high spots at both ends to bring the edge flat.

Hard to explain, but it does work. Anyway, thought I'd pass that on....
« Last Edit: April 20, 2015, 05:29:13 PM by vtsteam »
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Offline rowbare

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Re: Building a New Lathe
« Reply #167 on: April 21, 2015, 11:51:34 AM »
In one of the scraping DVDs I have (I think it is Richard King's) he describes scraping by zones to get rid of a taper. For example if you know that you usually remove about a tenth per pass and you are 1 thou high, divide the length into 10 zones. Starting from the high end, scrape the first zone. For the next pass scrape the first and second zones, for the third pass scrape the first, second and third zones and so on. Then once you have your alignment you finish scrape for flatness and bearing.

bob

Offline vtsteam

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Re: Building a New Lathe
« Reply #168 on: April 21, 2015, 12:25:30 PM »
I think I might have seen that video years ago, Bob. Did it have a segment at the end showing the casting of straightedges?

Anyway, that method would work, too. I do kinda like mine -- it only takes occasional measuring, and no special marking. They both finish up the same way once parallel is reached.

I also want to reiterate from the scraping yesterday (with my tools) that on narrow work, one filing is worth ten scrapings, and if anything is more than a thousandth off I can cut down hours of work by grabbing a handle-less coarse file, laying it flat and going at the high spots until I reach a thousandth or so rough tolerance. Nothing wrong with files!
I love it when a Plan B comes together!
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Offline vtsteam

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Re: Building a New Lathe
« Reply #169 on: April 22, 2015, 09:32:19 PM »
I've finished scraping 3 of the 4 way edges today and the fourth is about half way done. Just a progress update. It will be nice to switch to pattern making and casting shortly.
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Offline PekkaNF

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Re: Building a New Lathe
« Reply #170 on: April 23, 2015, 03:01:13 AM »
This is a thread I follw with great interest.

Any informative pictures on color transfer and scraped marks?

Pekka

Offline Joe d

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Re: Building a New Lathe
« Reply #171 on: April 23, 2015, 07:58:14 AM »
Sounds like you're making good progress Steve.

Looking forward to the first turning on the Model 1 Mark 1 Fletcher Ladder Lathe :clap:

Joe

Offline vtsteam

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Re: Building a New Lathe
« Reply #172 on: April 23, 2015, 09:25:02 AM »
Thanks Pekka, Joe.  :beer: I keep thinking photos of scraping must be as boring to people as scraping itself. But I can see that maybe a couple pictures of the blue part might be useful, so I'll take them.

One point I want to make about files. They are NEVER flat in my experience. If you realize that you can use it to your advantage (and if you don't, they will mess up your work).

So, flip your files over when filing and get a feel for which side is cutting in the center and which side is cutting at the ends. imagine how that is cutting the work. And then use the appropriate side for what you want to do and apply pressure in the area you want to cut, as well as keeping the stroke length right not to cut into areas you don't want.

With a file laid flat, you will be able to feel resistance in it along its length, and know where it is cutting.

On this level of flattening things, filing involves a lot of visualization and feel, you cannot rely on just the idea that a file is flat and rub it over a surface, because, guaranteed you work will suffer. Is the file following a curve, or cutting the ends like a double-ended scraper, or rocking at the center. You must feel and imagine what the action is.

And of course frequent checking to make sure you really are cutting where you want. This is especially important if you are new to this. As you get more familiar, knowing what file face you are using for a particular high spot becomes second nature.
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Offline Brass_Machine

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Re: Building a New Lathe
« Reply #173 on: April 23, 2015, 12:06:32 PM »
Thanks Pekka, Joe.  :beer: I keep thinking photos of scraping must be as boring to people as scraping itself. But I can see that maybe a couple pictures of the blue part might be useful, so I'll take them.

Nah, not boring at all. I find it interesting and it helps some of us.

Keep up the good work!
Science is fun.

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Offline vtsteam

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Re: Building a New Lathe
« Reply #174 on: April 24, 2015, 08:43:16 PM »
Okay, so here's the 4th edge blued up. It's been filed and scraped some already. the blue has begun to move on the left from a small spot to start with. the high area on the right is getting larger, too.

If the edge was also tapered and the right side was the wide side, I would  scrape everything blued except a small patch on the far left, which I would leave. When the straightedge was placed for a rub next go-round, it would ride up on the high spot on the left and mark high spots mostly toward the rght, which would force stock removal along a new straight line, angled inward more on the right.

Scraping those would have the effect of reducing the taper, yet maintaining a straight line. I'd repeat this process until the width of the scraped areas all along the ways measured the same -- in other words, parallel with the reference edge. Then I would continue scraping the whole ways, including the part left earlier to bring the whole surface into truth, and now parallel, too.

« Last Edit: July 11, 2017, 04:01:49 PM by vtsteam »
I love it when a Plan B comes together!
Steve
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