Cheapest lathe on ebay- An adventure

[YEMX]

...Or a mental case.  You decide!  This will be an ongoing post, until I finish this "build".

Months (or years?) ago, I bought the cheapest lathe on ebay, which at the time was $360 or $380 with free shipping to a residential address.  The intent was to use the majority of the parts and turn the 7x12 mini lathe into a 7x16.  This post isn't so much a review as it is a cautionary tale for anyone considering a 7x lathe.  I'm also bored and have no other projects to write about at the moment.  I also have been wanting to do a write up for a while.  This is going to be written as a stream of consciousness, so bear with me.  I'll sum this post up at the end, so if you'd like to just fast forward to that, feel free.  I can ramble on without end, so I won't hold it against you if you do.  Anyhoo, onto the post...

My main upgrades include:

16" bed kit
Taper roller bearings for headstock
Metal gears (ebay- these need work!! They're a bit rough)
4" chuck
Steel quick change tool post (QCTP) (ebay)

Recently bought (or soon to be) upgrades:

4" spindle (no need for an adapter plate, allows for less expensive chucks to be bought)
4" 3-jaw (larger through bore)
Conversion to Treadmill motor with new speed controller

With the cost of the lathe plus all the "Main" upgrades, I was into this project for less than half the cost of a 7x16 lathe, and have metal gears.  Which is why I went this route.  I discovered that this isn't exactly the case.  Though I'm still well under the cost of a 7x16, there's some... issues I ran into along the way...

Now, some of you undoubtedly will have other routes you'd take to solve the same issues.  Most of you probably wouldn't even waste your time with a 7x lathe.  For me however, this is the route that I took, and the 7x is enough lathe for any projects I have currently, or will have in the foreseeable future.  I do plan on upgrading to a larger lathe, but that will be much further into the future, when I can move my shop into the garage.  Because of both space and ease of setting up the machines.
 Anyhoo- onto my findings.

The 7x12 lathe I ended up getting is a "single speed" lathe- meaning I don't have a high/low range selector.  All of the one's I've seen whether on the web or Youtube, my type of lathe has a blue and white paint scheme. 

The Lathe I bought:


Anyhoo- that was the first difference between my lathe and say, a Harbor Freight (HF) lathe.  Another difference being that 99% of the 7x lathe's headstock casting has 3 holes to secure it to the bed, whereas mine has 4. 

Original bed:


New 16" bed:


But of course, the holes in my headstock don't line up to the holes on the 16" bed...  I could have modified the 16" bed holes, but I chose to buy "the correct" headstock casting from Little Machine Shop (LMS).  In fact nearly all my parts are from LMS, so unless I specify where I got the part from, assume that I got it from LMS.  So that was the second difference I found-  The single speed headstock casting doesn't properly fit the 16" bed.  The last thing so far that I've found, is that the lead screw mount on the right side (non-headstock side) isn't the same.  So I had to order a new one of those as well... 

Right side of old lead screw:


Right side of new lead screw:


Most parts are cheap enough- though the new headstock casting I cringed a bit, since it was $50...  I couldn't source one used.  Another issue I found (kinda- a Youtube vid tipped me off on it actually) was that the drive gear on the motor isn't the same pitch as the corresponding drive gear on the spindle.  Even if you do nothing else, get a new gear from ebay.  It's a 5mm pitch gear.  I ended up getting a 15 tooth gear.  You'll have to drill out the bore to fit the motor shaft.  My shaft is 8mm.  Which is a moot point now, since I'm upgrading to a treadmill motor, but I felt that I should mention it.  There's also a much better belt to use than the factory one.  Kinda pricey at $14, but it's absolutely worth it.  The belt is a Bestorq 425-5M-9.  I'll post a link below.  The description on the website is a little wrong, but having ordered it, it IS the correct belt. 

Are all my purchases necessary?  No.  The metal gears are loud, and rough when you first get them.  They'll take a little work.  The noise level won't change.  If you change these out, I'd wait until you break a plastic one.  Or, just change out the headstock gears.  Do you NEED to change out the original spindle for a 4" one?  Nope.  I did just because I can.  Also, the arguments of "surface contact is better" and "you get a little bit of space back" were compelling enough for me to get one.  Also, as I've stated, the chucks are cheaper, due to not needing an adapter plate- $131 at LMS vs $67 on ebay for a comparable 4" 3-jaw chuck.  Sure the cheaper chuck will need work, but what chinese part doesn't?  You could go either way with the QCTP- the cheaper aluminium one or the steel one I bought.  The steel one is more rigid, but for some, the aluminium one is rigid enough.  The only things I would absolutely recommend are the new taper roller bearings, and the new drive gear and belt.  Everything else can wait or simply not be done...  Bear in mind, the gear issue may only be specific to the lathe I bought-  Again, mine being "single speed" vs. a HF lathe having a high/low selector.  You can get a gear reduction kit w/a new belt on ebay which will have matching gears.  That kit won't work for me, since I have the single speed...  My belt connects directly to the spindle, where as the HF ones have a belt from the motor to a drive gear that then connects to the gear selector box... 

In conclusion, would I do it again?  Yes- but I would start with a HF one.  The parts are more universal and you'll save yourself some hassle if and when you upgrade to a 16" bed.  Also, you can inspect what you're buying before you get it home.  My lathe came with a broken carriage handle and a broken emergency stop button.  The safety switch connected to the spindle cover was terrible as well.  Later I found out that my tailstock handle was cracked as well.  You can avoid all that by buying one from HF.  I love to tinker, and with work these lathes aren't bad.  For me, these small lathes are good projects.  Many of you don't think so, and that's fine.  For me, my space available and projects, a 7x is perfect. 

In summary:

-  Headstock casting is different between my lathe and the "typical" 7x lathes.  Uses 4 bolts instead of 3 to mount to bed, and the holes are not in the same position as "typical" lathes.  It's a single speed, no high/low selector and associated parts.  Either modify bed (not advised, due to hole spacing) or buy a new/used HF type headstock casting.  Or don't buy the same lathe as I did from the start 

-  Right side of lead screw differs between old and new- a new right side lead screw mount is needed if upgrading to a 16" bed.  This only matters if you buy the same lathe as I did.  If you're starting with a HF or Grizzly, you're good.

-  Drive gear on motor isn't correct pitch.  Causes premature wear on belt.  New one is needed.  A 17 tooth, 5mm pitch will replace the factory gear.  I bought a 15 tooth gear to gain a touch of torque (though really, I'm not sure how much more torque I picked up, if any).  Upgrade the drive belt as well, factory belt is of low quality.  I suggest not going with the same ebay seller for the gear, it took over a month to receive them.  It was within the shipping window, so I can't complain- but over a month for 2 gears?  C'mon...   

Ebay link for gear:
https://www.ebay.com/itm/1Pcs-XL15T-Timing-Belt-Drive-Pulley-4mm-Bore-1-5-Pitch-For-10mm-Width-Belt/162282221784?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Link for upgraded belt:
https://3bgsupply.com/transmission-belts/synchronous-belts/425-5m-9-bestorq

[YEMX]

I got some of my parts in, the new right side lead screw mount fits beautifully, as does the new headstock casting.  The bearing cap from the original headstock did NOT fit, however.      No worries, I sanded down the O.D. a bit until it did...  When comparing the two bearing caps, the original one is JUST slightly too big.   

Still waiting on my new 4" spindle... 

The belt drive cover from the original machine fits, luckily!     I'll take what I can get at this point.     I may have to modify it depending on how I go about the Treadmill motor upgrade.  I'm still trying to figure out what pulleys to use and where to get them...  If anyone has suggestions, I'm all ears!

[YEMX]

I guess I forgot to update.    I got my 4" spindle a little while ago.  I'm waiting to get a 4" 3 jaw (I'll order it on the 1st) before I do any assembly.  There's also an upgrade I'd like to do to the tailstock, but I'm going to wait on that for a little bit.  I have a 4" 4 jaw independent, but I don't particularly want to mess with that just yet.  I'd have to take off the adapter plate, and I don't even have the motor yet, so I'm not in a rush.  I also received my new motor controller, and I'll also order a treadmill motor on the 1st.  Still have to figure out how I'm going to connect the two.  I know I'll be using a belt, but what pulleys, where to get them etc.  I also have to figure out how I'm going to mount the treadmill motor.  I'll probably just come up with a simple way to mount it to the workbench directly with a simple sliding mechanism to adjust belt tension. 

I want to make a new tailstock base plate and locking plate...  I'm still kicking around if I'm actually going to do it or not.  I WANT to do it...  I'll probably end up doing it in the end.  Or I'll curse myself later for not doing it    This is what I want to do:



Anyhoo, that's where I'm at now.  I'll update when I make more progress.

[Motorhead]

LOL ... just wait until you buy CHEAP tooling and figure out bottom rung is throwing your dollars away and buying better quality while it hurts up front is far and away the better choice.
And folks wonder why custom machined parts are often quite expensive beyond how simply a part may be ? ....  Time and tooling 

[YEMX]

LOL ... just wait until you buy CHEAP tooling and figure out bottom rung is throwing your dollars away...

Oh, I absolutely know what I'm getting myself into with cheap tooling.  For me, tooling costs depend on the project and material I'm using.  If it's hardwood, a resin cast piece, certain plastics or small bits of aluminum on a not-so-important project, I'm completely fine with cheap tooling.  If it's a more important part and a harder material, then I'll get tooling that's appropriate.  I'm not THAT silly!    Crazy and hard-headed for sure, but SILLY?  Naaahhhhh   

Heck, I kinda knew what I was getting into w/this chinese lathe project.  I didn't think some issues would pop up (headstock casting and such), but I'm still enjoying the project for the most part.  I'm also still well under the cost of an "actual" 7x16 lathe.  As far as I know, Micro Mark is the only place that sells a 7x16 (even though my bed is red, which is typically HF/Sieg- yet I've never seen a HF 7x16??), and that lathe is over $1500 with shipping.  I'm still below half that cost even with everything I've bought.  Plus digging into the lathe is fun for me.  Frustrating at times for sure, but still fun.

[YEMX]

4" three jaw came in a little while ago.  Still wrestling with how to do the treadmill motor.  I need to use the spindle bore for barrels, so attaching a larger pulley to the end of a shaft and having the shaft attach to the lathe via friction inside the spindle bore (SOP with many people who do the treadmill motor conversion) is a no-go.  I have a plan- I just need to get the motor first, and see what's what before buying some pulleys to test.

I'm going to start modifying the original control box as well, I want to configure it the way I'd like it set up for future use.  I'm also going to start getting some other small electrical items so I can start laying out the control box as I'd like it.  Nothing new or crazy, the main layout is going to be very similar to this:



Anyhoo, I'll update when I have something more interesting to show/talk about

[YEMX]

Nothing much to update, gotta wait until the 1st to get the treadmill motor.  Then I can start making more accurate plans.  I've been wracking my brain on trying to figure out a way to drive the lathe via the treadmill motor, without having to use the spindle bore...  I think I'm just going to have to use an intermediate shaft-  It'll ride on two pillow blocks...  I'm thinking one end will have a pulley that goes to the lathe, which is the just the "factory" type pulley- 15T 5mm pitch.  The other end of the intermediate shaft would have a larger pulley that connects to the treadmill motor, and that way, I'll get my 3:1 gear reduction...  I'm still trying to figure out how exactly it'll all mount, attach and be adjusted.  But for now, I think having an intermediate shaft will be the easiest route to take.  The only other way I could possibly think to go would be to have an extension made that would thread onto the end of the spindle, taking up the spot of one of the spindle nuts.  I don't know...  Eh- it's another option...  So what do y'all think?  Which way should I go:

Intermediate shaft?
Spindle extension?

I've started to modify my original control box as well.  Baby steps people, baby steps!    I'm considering adding a few options to the box.  Not sure yet.

[MJP]

How about Powerlock coupling on the spindle shaft, leaves the spindle bore free?

That way you can couple any belt pulley on the shaft.
Or have I misunderstood something?

Marko

[YEMX]

How about Powerlock coupling on the spindle shaft, leaves the spindle bore free?

That way you can couple any belt pulley on the shaft.
Or have I misunderstood something?

Marko

Let me check this out...  Many thanks!

The only issue that needs be overcome, is that I have to set the pulley that would be on the spindle away from the gear-train.  That's the only reason I can't attach a larger pulley directly to the spindle.

[YEMX]

Idea on motor mounting- not mine.  Saw it in a FB hobby machining page I belong to.  There's a guy that uses the intermediate shaft idea that I had, along with pillow blocks...  But he mounted the treadmill motor and intermediate shaft under the table top (upside down), and ran the belt through the benchtop to connect to the lathe...  Very clean set up!  He also set everything up on some t-slot aluminium extrusions so that everything is pretty much in-line, and adjustable!  I'm probably going to go this route- maybe not the underside mounting, but I'll probably end up using those aluminium extrusions to mount everything! 

[nced]

LOL ... just wait until you buy CHEAP tooling and figure out bottom rung is throwing your dollars away and buying better quality while it hurts up front is far and away the better choice.
And folks wonder why custom machined parts are often quite expensive beyond how simply a part may be ? ....  Time and tooling 

LOL....so true! After I bought my cheap 7x10 Harbor Freight "box of outta spec lathe parts assembled by orangutans" for $295 (decades ago), replacing the 10" bed with a 14" bed, adding a quick change tool post and holders, buying tool bits and other gadgets, buying a larger chuck, so on and so forth the "lathe ended up costing a bit over $800, plus I still had to spend a lot of time modifying the tail stock adjustment method for easier/better/more accurate adjustment. The motor would get bogged down with even lite cuts in steel and the fuse would blow. Then after quite a "fuse blows" over time the circuit board blew protecting the fuse leaving me with only max spindle speed! LOL, after pricing a replacement circuit board and finding that it cost about 1/2 what I originally paid for the 8x10 lathe I scrapped the lathe and replaced it with another Chinese bench top lathe that used stepped pulleys and a belt to change speeds. The replacement really wasn't as large as I would have liked (only a 3/4" spindle bore) I've been using the 8x14 LatheMaster for over 15 years now and it still does the job.
The 7x10 HF minilathe with 14" bed and a few other accessories.........


My current "still too small" 8x14 LatheMaster (no longer available)......


HF calls it an 8x12 but it is actually an 8x14. The Lathemaster CQ6120X320 is the same lathe, made in the same factory. (HF version about $900 now)..........
https://www.harborfreight.com/8-inch-x-12-inch-precision-benchtop-lathe-44859.html

 

[YEMX]

Oh yeah, totally understandable about getting something better from the get-go.  But as you already know, the 8x lathes still only have a .75" spindle bore.  The 9x lathe's aren't much better.  The 10x lathe's are a bit better at a hair under 1". 

The main problem now is that my workshop has to be in the basement, and I have no help/space to put larger machines in.  I'm not that old, but I'm old enough that I don't even want to attempt wrestling with machines that are over 1,000 lbs down stairs and with no way to easily lift said heavy parts onto machine stands.  But in the future, when I can move the shop out into one of the garage bays, I'll absolutely upgrade to larger machines.  When I upgrade, it'll be to a 12x36... Spindle bore is 1.4", and it will be more than long enough for any job I'll ever have. 

Right now, cost is also a factor.  Even with all the money I've spent so far in parts, I'm still only in for under half the cost of a Micromark 7x16 (and the Micromark doesn't come with metal gears, 4" spindle, chuck, or a steel QCTP).  I don't know of anyone else selling a 7x16, so Micromark's pricing is what I'm basing everything off of.  At the end of it, I'll have had a fun (and frustrating  ) journey with this mini lathe build, and it meets all my current AIRGUN needs. 

As soon as I can "move the shop" into one of the garage bays...  Oh man, it's ON!!!  6x26 mill, 12x36 lathe, sub panel with 220W for various machines... Plus everything will be relatively easy to move in since it's a straight shot for the delivery truck.  I'll also have room to use an engine hoist and such to help move everything around.  No stairs to deal with.  Oh yeah...  Much better!   

[YEMX]

Was FINALLY able to order my treadmill motor today- found a good used 2.9 HP motor...  1.75 HP continuous duty...  That should be more than enough for this build! 

The adventure continues...  I'll update when it comes in.

[YEMX]

I haven't forgotten about this project!  But I ran into some issues.  Basically, I need a lathe to finish the 7x lathe.  There's parts I need to modify and make to do final assembly of the 7x.  Also, with this new lathe inbound, I have to re-think where I'm going to put this lathe...  Not getting rid of it, though.  Anyhoo- I ended up getting a 8x16 with a 1.5" spindle bore.  Once I get the new lathe, clean it and set it up, I can get to figuring out how to proceed with the 7x.  Just wanted to update the thread a bit.

P.S. That treadmill motor did come in.  Now I just have to figure out how I want to mount it and such.  I have everything I need for the conversion, except the pulleys and belt(s). 

[Thatvan]

Out of curiosity where did you get the 16” bed? I have seen some on AliExpress for just shy of $300 shipped but that seems steep for a lather I picked up used at $100. 

[YEMX]

Out of curiosity where did you get the 16” bed? I have seen some on AliExpress for just shy of $300 shipped but that seems steep for a lather I picked up used at $100.

Used to be available at LMS.  With stuff going on w/china, not sure how availability is.

[Cloud 9]

I appreciate all the work you put into this, but I enjoy making parts not modifying, working on and troubleshooting my lathe.  I bought what I needed and could afford, and then started using it.  Nice writeup.

[YEMX]

I appreciate all the work you put into this, but I enjoy making parts not modifying, working on and troubleshooting my lathe.  I bought what I needed and could afford, and then started using it.  Nice writeup.

Weird flex, but okay...

[Thatvan]

I found one off Aliexpress. $120 shipped. Need to finish some wood projects in the garage before I switch back to the micro machine shop and try it out.

[YEMX]

I found one off Aliexpress. $120 shipped. Need to finish some wood projects in the garage before I switch back to the micro machine shop and try it out.

You found a 7x lathe for $120??