# Scraping a mini lathe?



## Sdmf5150

Probably a silly question, but I was wondering if anyone has scraped in one of the Chinese mini lathes.
I want to learn more about scraping and thought it might be a good project to see how smooth and accurate they could be made.


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## Asm109

Sure. Why not.  You get practice on a practical item and your downside if things go pear shaped is modest.  
At a minimum you will learn how to measure and see how accurate your lathe is to start.

Lastly, if everything goes south all you have to do is edit the title of this thread to Scrapping a mini lathe.


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## tertiaryjim

Scraping in my 13-36 crappy lathe made a world of difference.
Many complain about the mini lathes but I'm certain they can be much improved.
Study it and gather your surface plate and measuring tools first.
Then, you can check to see if it needs scraping before purchasing or making scraping tools.
This will also assure you know how to properly check the component alignments and give you time to 
make any jigs or tooling needed.
Don't forget that the surfaces will need to be flaked as well.
Those dovetails are a killer to flake by hand and most of mine look like a steel clawed chicken was grubbing for worms.
On the other hand they retain oil and move smoothly on the mill/drill I'm completing. 
The lathe is scraped in but I will need to tear it back down to flake it.
I did the lathe one component at a time so had to tear it down several times.
This was a pain but it worked out as I found just properly spreading the blue and using the surface plate
requires learning. Each time I tore the lathe down I re-checked the compleated components and found they needed 
more work as my skills had improved so I was better able to expose and see the flaws I had left.
Gibbs can be a real pain to make, they warp badly during machining, but it's fine to shim the old gibbs if they 
were properly made at the factory.  Many/Most weren't.
Many cheaper machines were so poorly built that even a crappy scraping job will make a incredible improvement.


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## royesses

There is a post somewhere on this forum where one of the machinists scraped in a mini lathe for his young son. Try searching mini lathe modifications

Roy


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## fitterman1

I've scraped my G0602 headstock, crosslide and compound and it made a huge difference to smoothness and accuracy. Haven't touched anything else yet. I know my tailstock is high because I lowered my headstock by about 006". Good thing about doing this is you can control to the nth degree all the geometrical tolerances of your machine, and you know where you stand in that regard. Working out the sequence of how your going to go about it can save you future rework. I suggest if your going to scrape your cross and compound slides and you decide to flake them, flake them a little sparser towards the extremities so those small depressions don't collect the fine particles that will eventually become a grinding paste.
Some serious measuring gear won't go astray either.
cheers


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## Sdmf5150

Where is a good place to get straight edges? I have seen the ones Richard King sells but I think they ar too big


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## fitterman1

Dunno, I live in Australia and they're rarer than rocking horse sh_t here. They have to be selfmade here I reckon.
 cheers


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## machPete99

I "scraped" in the saddle and tailstock of my minilathe using needle files.
Also replaced the standard spindle ball bearings with tapered roller bearings (intended for auto wheel bearing use), which ran much smoother.
Shimmed headstock and tailstock so inline with bed and each other.
Its fairly accurate but still very wimpy in terms of size of stock and DOC that it can comfortably handle.
Bought a Clausing and now do most of my work on that.
The minilathe did make the bushings needed to get newer bearings to fit the Clausing, Its also good for small work.


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## homebrewed

Home Shop Machinist published a series of 10 articles about scraping small items, including a mini lathe.  The first one with the mini lathe info appeared in the September/October 2012 issue and the last one was in the November-December 2012 issue.  They do sell reprints.  There was enough there to make a book on the subject but that doesn't seem to have happened.  The earlier issues include info on how to make your own scrapers and a diamond-charged grinder to shape and sharpen carbide scrapers.

Mark


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## addertooth

homebrewed said:


> Home Shop Machinist published a series of 10 articles about scraping small items, including a mini lathe.  The first one with the mini lathe info appeared in the September/October 2012 issue and the last one was in the November-December 2012 issue.  They do sell reprints.  There was enough there to make a book on the subject but that doesn't seem to have happened.  The earlier issues include info on how to make your own scrapers and a diamond-charged grinder to shape and sharpen carbide scrapers.
> 
> Mark


Bummer, I just checked, and some of the issues in the ten part series are no longer available.  However, they incorporated the topic of scraping mini-lathes in a separate book for the mini-lathe.  The book is about 29 bucks.


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## Aaron_W

addertooth said:


> Bummer, I just checked, and some of the issues in the ten part series are no longer available.  However, they incorporated the topic of scraping mini-lathes in a separate book for the mini-lathe.  The book is about 29 bucks.



Richard King sells a DVD on how to scrape. It is going on my Christmas list this year.


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## homebrewed

addertooth said:


> Bummer, I just checked, and some of the issues in the ten part series are no longer available.  However, they incorporated the topic of scraping mini-lathes in a separate book for the mini-lathe.  The book is about 29 bucks.


I wasn't aware of the separate book, good to know!


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## addertooth

addertooth said:


> Bummer, I just checked, and some of the issues in the ten part series are no longer available.  However, they incorporated the topic of scraping mini-lathes in a separate book for the mini-lathe.  The book is about 29 bucks.


For the record, I just bought the book minutes ago.  It will probably take a couple of weeks to show up. 
Here is the link to the book:
The Complete mini-lathe workshop


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## homebrewed

I'd be interested to know if the scraping section was written by Michael Ward, the author of the 10-part series.  It looks like the scraping topic is just 3 or 4 pages long so there can't be a whole lot of in-depth discussion on the subject.


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## Richard King 2

I have smaller straight-edges.   Before scraping it, you may want to check how bad it is first.  Then have it ground or planed and then scrape it for oil pockets.  The bed is the hard part.  Fitting the other parts are easy scraping.  You could bring some of the part to a class where I would teach you to scrape.  I have a class in 10 day in Minnesota.  If you can't make it, but the Edward Connelly book.  Machine Tool Reconditioning.  I sell them on ebay and will give you a 10% discount by private messaging me.   We had plans on a class in Springfield VT but we had to cancel it because of Covid and some Canadians could make it..


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## MrCrankyface

I scraped my minilathe when I had it, it was pretty much a must since the uneven thickness caused binding at certain places.
After scraping I could run the gibs tighter and still have a smoother travel.
Start with measuring with a micrometer along the ways to get an idea of how uneven it is.
Another fairly big upgrade is bolting it to a thick and solid plate of steel, it will make the bed a fair amount stiffer.


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## matthewsx

This is one of those things where you have to ask, just because you can does that mean you should? It'll certainly make it better than when you started but the big question is would your time be better spent on another project? Only you can answer that question.

John


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## macardoso

I'd say go for it.

I have made a little foray into scraping and here's my thoughts:


Financially speaking, it doesn't make sense for the machines we work with. Takes too long and if your time is worth money, you're better off getting it ground at a good shop for a few hundred bucks.
Physically it is quite tiring, especially hand scraping. I'm 27 and my arms/hands would be pretty beat by the end of a session.
The tooling and instruments (scraper, surface plate, indicator, straightedges, etc.) to do the job are expensive and you'll likely need to machine and scrape your straightedges before using them. Estimate $1-2k if you have nothing to start with.
Understanding geometric errors and knowing how to correct them is much harder than scraping a surface flat.
Scraping is a great way to improve what you have, especially if you don't want to spend the money on higher end machines and you have time.
When complete, the results feel worth the effort.
Scraping the top and bottom of my milling vise bed flat and parallel (2 surfaces, approximately 4 x 14") took me 45 hours. They were out quite a bit, but so is most import stuff. This was my first practice/learning project and I likely took the finish further than was necessary. In the end I took the wedge and bow out of the bed (0.0035") and got the surfaces flat and parallel within 0.0002" all over. If I had access to a 6x18 surface grinder, I probably could have completed the job in 2 hours with similar results. Obviously less practical on a full machine.


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## Richard King 2

A friend of mine and student who has taken 5 of my classes has a good You tube show on scraping a Myford lathe.  It has flat ways.  He has several others on rebuilding and scraping.  I also sell a DVD and HSB stick on scraping to get you started. I sell it on ebay or direct.  Message me.


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## pigpen

matthewsx said:


> This is one of those things where you have to ask, just because you can does that mean you should? It'll certainly make it better than when you started but the big question is would your time be better spent on another project? Only you can answer that question.
> 
> John


I scraped in a mini lathe. It was worth it because learning the skill was fun. What i didn't know before starting was how much of a skill it actually is. I thought the actual act of scraping metal was the hard part. I learned quickly that the physical act of scraping was the easy part. Measuring, and understanding the how and why of measuring took a ton of research and learning. The payoff is that all of that knowledge you learn can then be applied to all other aspects of machining. The scraped in mini lathe is just a side bonus. Connelly's Machine Tool Reconditioning (as Richard often suggests) should be the starting point if you really want to understand the fundamentals of measuring, aligning, and scraping.


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## Richard King 2

It's a coincidence but I have a student from Road Island next week who has a mini lathe he wants to scrape.  I thought he was the poster, but no it wasn't.  I invited him to join our forum so he can learn from everyone.   He signed up for my next week scraping class.  He said he might bring the bed in his suitcase.....lol    Anyway, hopefully he will join and as he scrapes his machine he can add some pictures....


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