ShopShoe's Mini-Lathe Upgrades

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As you may know, I've been more busy outside the shop than inside it because of
family adventures and illnesses.

I've been working on several projects for quite a while now, and it's probably time to turn some bits and pieces into threads. I also bit the bullet and started paying into Photobucket so I hope you can see my photos.

One of the decisions I made a few years back was to continue using the 7x MiniLathe and to work to make it better, despite my desire to find another lathe.

As it stands now, it looks a little strange with some of the modifications in place, but it is definitely better in operation.



For others with one of these, I'll include some history of my choices.

Before starting, the bed was "bellied" due to a poor casting, and the controls were getting erratic. The 3-jaw chuck was badly eccentric with worn jaws, but I really liked having it installed most of the time..

Since I'm in the USA, I took advantage of LittleMachineShop for some, but not all, of the parts. I have to be honest to report that I started before COVID, so supply was good and prices had not risen. (And I have to add the disclaimer that I am not related to LMS other than as a satisfied customer.)

I started with the 16-inch bed extension, which was supplied with not only the bed, but leadscrew, gear rack, and other parts.

The bed arrived in red, but a cross-reference chart for colors to match the other brands is supplied. I used a Ford color to match my "Cummins" paint scheme. Before painting, I masked the ways with layers of duct tape and knocked as much scale and roughness off the rest of the casting and sanded non-critical surfaces as well as I could. After sanding, I removed that tape, cleaned everything with solvent and remasked with masking tape for painting. The goal of all that was to provide fewer places for chips and dirt to stick or hide. I waited several days after painting before assembling.

I also ordered the parts to convert all the leadscrews and dials to solve the mini-lathe's unusual calibration and convert to a standard .001 inch-per-increment. I debated using the metric parts instead of the US ones, but I decided to stay with inches.



I replaced the headstock bearings with tapered roller bearings. If you contemplate this, there is a bushing that needs to be replaced or modified as the bearings are axially larger than stock. I ordered the bushing. On reassembly, I replaced the main drive gears with metal gears, but I decided to keep the plastic change gears to save money. This was pre-COVID, so one could buy quite a few replacement gears for the money the metal ones cost. I did buy a few replacement gears, and I also bought a 21-tooth gear that they sell to make better combinations for metric threading, which I do from time to time.

In a previous upgrade, I had scraped the saddle, so I made sure that that was still OK. I added tapered gibs this time, and it was an improvement over the shims I had used previously.





I also added way wipers this time, making the covers for them from aluminum sheet and using pieces of the felt that can be salvaged from old inkjet printers.





In mounting the way wipers, I found the casting for the saddle to have some hard spots and voids where I wanted to put threaded holes, so screws don't quite line up. I decided to live with it, but I came close to buying a new casting.

My lathe has always suffered with an inconsistent engagement of the half-nuts, so I scraped the dovetails where the bracket rides and tried to improve the small gib it uses. I also made a better retainer and retapped the screw holes and used new screws on reassembly.

I had previously lapped the dovetails and gibs on the compound and cross slides, but I worked on it again, and checked the alignments of everything very carefully.

I had earlier rebuilt the mechanism used for the tailstock advance and installed a new handwheel. This time I replaced the main saddle handwheel with a similar one. It so nice to have a handwheel run true and a larger handle to turn it.





I have the lathe mounted to its stand, so before putting it back in place I releveled the stand and checked everything carefully. It is mostly just held in place, not tightened down. This is because I don't like chasing machines around on a tabletop.

To complete this round of changes, I bought a Bison precision 3-jaw chuck. It was over $350.00, but it was worth it. Centered up on the spindle with a test bar and dial indicator, it is below 0.001.





I'll close this post here, and come back with some accessories I have added and some further upgrades I may do:

--ShopShoe
 
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Accessories:

Some things I have done that are not direct modifications, but useful:

QCTP: OXA size. I have made extra and special toolholders and plan to make more.



Drive accessories for between-centers turning and use with faceplate.

Hand crank for spindle. I used a stock 6-inch machine handwheel.



Ball-turning attachment: A perennial project on these forums.



ER-25 collet holder and collets: It was a sale special a few years back, and works very well. As a test, I was able to turn pieces from plastic ball-point pen fillers. The disadvantage of this particular collet holder is that it does not allow stock to go through the headstock.



I also have MT-3 collets for holding a test bar for alignment testing. The fewest number of parts in the setup should make the tests more accurate.

--

What Else?

At this point, there are still some things to consider:

Additional screws on the compound and cross-slide gibs. Maybe pin the gibs. I bought the screws, but did not do this yet.

Purchase all the metal gears.

Convert the tailstock to lever-lock from the stock version. I am "on the fence" with this because I sometimes find the wrench-tightened adjustment sliding down the ways and I wonder whether the lever-lock would hold as tight as the nut.

Build a better steady rest. The stock one is very clumsy to install and remove. I think I want one that can be installed without undoing the tailstock center and that has a better securing means than the existing nut and stud.

Motor Upgrade. Probably only if the existing motor fails.

--

I'll have some further thoughts in a post to follow:

--ShopShoe
 
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Closing Thoughts:

When I bought this lathe several years ago the cost of these machines was around $400.00 and this one was on sale for about $350.00. I spent extra cash back then on a 4-jaw chuck and a milling attachment. I worked without a mill for about a year and was successful that way. In inflated COVID prices, the current version is priced from from $950 to over $1000.00.

The other machines I was considering at that time were the 9X19 lathes and TAIG and Sherline. The 8.5 inch lathe with powered cross-feed was not yet available. The 9X19 could not do left-hand threads and had some other issues I did not like and I wanted screw-cutting ability and more capacity than TAIG and Sherline offered. I chose the 7x because I thought it had a comprehensive list of features I could use to learn things I wanted to learn. There are also enough of these lathes out there to have a support base.

I have got what I needed from this lathe and I have definitely learned a lot about fine-tuning lathes in general (As has been said, "Consider Them a Kit" )

By continuing to adapt and modify this lathe I feel that it is now brought up to my abilities and it is still small enough to move if I move and also large enough and featured enough to do a lot of the projects that I want to do. Parts are available and not unduly expensive. Nonetheless, I have invested lots of money and time in this lathe.

I do want another lathe or two to fit all the things I want to do now, but the little 7x can still fill a few needs as I work in those directions.

Could I use another 7x? Maybe? I have considered getting another one and making it metric (I know that may be crazy in the USA, but I live happily in metric in a lot of cases and it might be fun.) I have also considered adding the 8.5-inch lathe, or the 9X19 and adding one of those to my complement of machines. My true desire is something 12x36 or larger with quick-change gearbox and D1-xx chuck mount. Unfortunately, I don't have the shop space or the electrical capacity for something in that range.

Whatever I add to my machine collection, I'll post it.

Thank You for Reading.





--ShopShoe
 
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Shop shoe: It's too bad you don't have the room. After many years of adapting to my old SB Heavy 10's faults and wear I finally bit the bullet, re-arranged my workspace and got a generic 12x36 in Mar 2021. Mine is a King but identical to Grizzly. Had a Q.C. box on the old S.B but the gearhead and D1 headstock and 2H.P. metric thread capability plus unworn ways make this a treat to use. Well worth the price and the work to dismantle then re-assemble in my basement shop. When I'm gone and the house is sold the lathe goes with it!
Colin
 

howard002

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As you may know, I've been more busy outside the shop than inside it because of
family adventures and illnesses.

I've been working on several projects for quite a while now, and it's probably time to turn some bits and pieces into threads. I also bit the bullet and started paying into Photobucket so I hope you can see my photos.

One of the decisions I made a few years back was to continue using the 7x MiniLathe and to work to make it better, despite my desire to find another lathe.

As it stands now, it looks a little strange with some of the modifications in place, but it is definitely better in operation.



For others with one of these, I'll include some history of my choices.

Before starting, the bed was "bellied" due to a poor casting, and the controls were getting erratic. The 3-jaw chuck was badly eccentric with worn jaws, but I really liked having it installed most of the time..

Since I'm in the USA, I took advantage of LittleMachineShop for some, but not all, of the parts. I have to be honest to report that I started before COVID, so supply was good and prices had not risen. (And I have to add the disclaimer that I am not related to LMS other than as a satisfied customer.)

I started with the 16-inch bed extension, which was supplied with not only the bed, but leadscrew, gear rack, and other parts.

The bed arrived in red, but a cross-reference chart for colors to match the other brands is supplied. I used a Ford color to match my "Cummins" paint scheme. Before painting, I masked the ways with layers of duct tape and knocked as much scale and roughness off the rest of the casting and sanded non-critical surfaces as well as I could. After sanding, I removed that tape, cleaned everything with solvent and remasked with masking tape for painting. The goal of all that was to provide fewer places for chips and dirt to stick or hide. I waited several days after painting before assembling.

I also ordered the parts to convert all the leadscrews and dials to solve the mini-lathe's unusual calibration and convert to a standard .001 inch-per-increment. I debated using the metric parts instead of the US ones, but I decided to stay with inches.



I replaced the headstock bearings with tapered roller bearings. If you contemplate this, there is a bushing that needs to be replaced or modified as the bearings are axially larger than stock. I ordered the bushing. On reassembly, I replaced the main drive gears with metal gears, but I decided to keep the plastic change gears to save money. This was pre-COVID, so one could buy quite a few replacement gears for the money the metal ones cost. I did buy a few replacement gears, and I also bought a 21-tooth gear that they sell to make better combinations for metric threading, which I do from time to time.

In a previous upgrade, I had scraped the saddle, so I made sure that that was still OK. I added tapered gibs this time, and it was an improvement over the shims I had used previously.





I also added way wipers this time, making the covers for them from aluminum sheet and using pieces of the felt that can be salvaged from old inkjet printers.





In mounting the way wipers, I found the casting for the saddle to have some hard spots and voids where I wanted to put threaded holes, so screws don't quite line up. I decided to live with it, but I came close to buying a new casting.

My lathe has always suffered with an inconsistent engagement of the half-nuts, so I scraped the dovetails where the bracket rides and tried to improve the small gib it uses. I also made a better retainer and retapped the screw holes and used new screws on reassembly.

I had previously lapped the dovetails and gibs on the compound and cross slides, but I worked on it again, and checked the alignments of everything very carefully.

I had earlier rebuilt the mechanism used for the tailstock advance and installed a new handwheel. This time I replaced the main saddle handwheel with a similar one. It so nice to have a handwheel run true and a larger handle to turn it.





I have the lathe mounted to its stand, so before putting it back in place I releveled the stand and checked everything carefully. It is mostly just held in place, not tightened down. This is because I don't like chasing machines around on a tabletop.

To complete this round of changes, I bought a Bison precision 3-jaw chuck. It was over $350.00, but it was worth it. Centered up on the spindle with a test bar and dial indicator, it is below 0.001.





I'll close this post here, and come back with some accessories I have added and some further upgrades I may do:

--ShopShoe
 

howard002

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I bought one of the pretty red Chinese lathes. Talk about the dunbass thing to do. It came out of the box very crude and some things really needed to be fixed in a machine shop and under warranty. Well the half ass person who sold me the lathe fix it myself or pay someone else to fix it for me but he was not going to honor any warranty on the new machine, and this guy sells machine for a reputable manufacturer, so be careful when getting ready to make a purchase of a new machine. I have a few upgrades to add to my lathe once I get it ready to put back together. Bed ways and other places are very rough and are nowhere close to accurate. Now that Xmas is over I might be able to get it back together and start turning things.
This is just food for thought, many many so called sellers out their are nothing but scammers, you must be very careful and question absolutely everything and if you have any doubts, move on to a different seller.
Cheers and Happy New Year to all,
H
 

howard002

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Here is a question I have that maybe someone out their might be able to help me with.
I have a 7X14 Chinese lathe, it came without a RPM meter, so I bought a RPM kit, but my concern is no diagram as to hookup
the wires so as not to short out the meter. I have the speed adjustment "POT" to adjust the speed but no meter to tell you what speed is
the chuck moving.
All help very much appreciated,
H
 

Richard Hed

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I bought one of the pretty red Chinese lathes. Talk about the dunbass thing to do. It came out of the box very crude and some things really needed to be fixed in a machine shop and under warranty. Well the half ass person who sold me the lathe fix it myself or pay someone else to fix it for me but he was not going to honor any warranty on the new machine, and this guy sells machine for a reputable manufacturer, so be careful when getting ready to make a purchase of a new machine. I have a few upgrades to add to my lathe once I get it ready to put back together. Bed ways and other places are very rough and are nowhere close to accurate. Now that Xmas is over I might be able to get it back together and start turning things.
This is just food for thought, many many so called sellers out their are nothing but scammers, you must be very careful and question absolutely everything and if you have any doubts, move on to a different seller.
Cheers and Happy New Year to all,
H
Tell us who it was who did this. As long as you can prove it to be true, it is not anything you can be sued for telling us., Libel? Did you take photos?
 

cl350rr

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Thank you for sharing your modifications. I bought a HF 7X10 a few years back and find it to be a fairly useful machine. If you don't mind I have a few suggestions based on your pictures above. The first thing I did was to change out the screws holding on the cross slide and compound rest handles, every time I turned them I took a layer of skin off my knuckle.

Second, when I first started learning machining I was shown that every movable part on the lathe had an oil cup and all of them are there for a reason. I was told to oil them before each work session if I wanted the machine to last. So I found some small spring-ball oil cups online and bought a 100 or so, drilled and installed them all over the lathe.

Please excuse the chips in the picture
 

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Makerphil

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I made the following modifications to my minilathe:-

1. Carriage clamp to stop the carriage moving when facing off.
2. Compound slide clamp to improve rigidity when parting off.
3. Plastic shield for the carriage gears to stop swarf jamming up the carriage movement.
5. Removed all the screws from the rear splash guard and replaced them with two thumb screws to enable easy removal for cleaning and servicing.
6. Hand crank which expands into the headstock to ease threading using dies and tool thread cutting - lowers personal stress! Remember to remove the power plug before using and the crank before putting power back on.

Some etails of these modifications can be found on YouTube.

i subsequently sold my minilathe and purchased a larger lathe but i learned a lot using it and managed to make a Stuart S50 mill engine.
 
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Thank You everyone for taking the time to add to this old thread.

Things are still as they were when I finished the original post. I am still happily using this lathe until something else takes over.

--

Howard002,

I am sorry that your experience was so bad. One thing that one learns from machines built and sold by some of these overseas manufacturers is not only is quality poor a lot of the time, but it is also extremely variable from example to example. I might also suspect that things have deteriorated quite a bit all over the world during the pandemic and associated events. Some things may be being made from from parts pulled from the scrap bins just to get anything put out on the market.
--
I was not aware that there was a tachometer kit available for the 7x lathes. Can you post a link?

--ShopShoe
 

Lloyd-ss

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Seeing mods that others have done is always helpful. I like the larger handwheels and the oil-cups. I might try both of those.

Regarding quality issues on machines and parts, yes, it is annoying. I always try and figure out ahead of time: am I buying at the top or middle or bottom of the price range? If at the bottom, I am prepared for problems and usually end up fixing things myself. For me, its not worth the fight of returning and not knowing if the result will be any better. I remember when I bought my first lathe, it was in-person at the Grizzly store in PA. I was talking to the salesman, a low-key retired machinist who seemed pretty honest and not pushy. I asked him about taking the lathe apart and working on it to fix or improve minor issues. Is that OK??? His reply was, "Well, if you don't like doing that sort of thing, you probably shouldn't be buying a lathe at all." How true.
The take-away was: once you buy it, its yours.
Lloyd
 

hanermo3

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Lathes have always been the king of machine tools.
Any lathe can be made better --
and any lathe is less than perfect.

The more or less best small lathes in the world were the original Schaublins from switzerland.
About 9x in size, with a 200 kg cast iron bed/cabinet.
They cost about 60.000 € these days.
Schaublin went bankrupt at least twice.

And the monarch 10EE lathes, about 105.000 $.
Still made to order.
Monarch went bankrupt or was sold.

German lathes are still available that surpass the schaublin and monarch.
Weiler is one brand.
It´s available from rebuilders in germany that deliver 1 micron HS and TS accuracy and 1 micron TS linearity.
Videos on youtube.
About 40k+.

When I get the next disposable money to spend 50k€ on a toy I will buy a weiler or similar.
And then re-fit it with the best cnc kit in the world.
Not because I need to, but because I want to.

Just like I want an NSK Nakanishi spindle for a router and engraving.
It´s just unbelievably good.
6k.

Perfect just means you are not measuring close enough.
E. My 2400 kg vmc built in steel flexes when I hang from the center span.
A machine builders square shows the flex quite clearly, and it repeats very well.

E:
A Mori Seiki DCG VMC can cut an interpolated hole in steel to 0.0007 mm, 0.7 microns, in roundness.
Videos on youtube.

E:
Amateurs routinely lap telescope mirrors to better than 0.1 microns in roundess and flatness, by hand work.
Measured via optical flats and helium-neon lights.

E:
A couple of very smart pros in the uk with no experience hand-lapped an south bend old lathe to submicron accuracy, and then used it to make parts to create the first ruling engine.
This was a grating engraved with a diamond tip, to several thousand lines / mm iirc.
So it refracted light waves.
There was an article on scientific american that was later paywalled.
Copies axist.
It took them 17 years, more or less, iirc.

E:
It took me more than 10 years and more than 70.000 work hours to make a decent VMC from scratch.
And I´m still working on parts of it, distracted multiple times by other work.
And I did it 5 times, always improving on stiffness.

E:
Like our sauna, now almost complete.
Needs maybe 2-6 more work days for finishing.
After about 1 year, and lots of work hours and money - mostly because I broke both my knee ligaments and was hors de combat for months.

My point is:
YOU can make anything excellent, surpassing common commercial offerings, if You actually really really want to.
Most stuff costs peanuts in tools, a few hundred will get one doing world-class work.
 
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Talking about minilathes and excellence in precision don't forget the all-American Levin lathes 9 1/2 " between centers, available from about $ 20.000,-upwards. Their 1938 book 'Practical Benchwork for Horologists' for watchmakers, instrumentmakers and machinists has something of a cult status over here.
 

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