Starting Mini-Lathe Mods

[cfellows]

Nearly finished with my toolpost compound. I decided to make a toolholder which takes a standard carbide insert. I still have to make the clamp and screw to hold the insert down and I have to make or buy a more suitable handwheel. Finally, I need to add the height adjustment stud and nut. It looks like I'll also have to mill some off the bottom of my tool post since the insert needs a little more vertical adjustment room.

The overall travel is 1.25". Think this will be perfect for cutting valve faces and other angular turnings.

Chuck

 

[zeeprogrammer]

Watching with interest Chuck.
That looks nice. With my limited experienced I've had decent luck with carbide inserts.

 

[alcostich]

Chuck,

Any chance you could give some dimensions for the jig for the tangential tool bit jig?
Thanks.

Alan

Here are some pictures of the jig I made for grinding tool bits for the tangential holder. It's made from a hunk of aluminum to help conduct heat away from the tool bit. I use the jig with my 2" x 48" vertical belt sander. Cuts fast and relatively cool.

 

[Blogwitch]

Chuck,

All this lot is great work on your part, very professional looking. But I would like to transport you back a few posts to your leadscrew.

Have no worries about it, it is very easy to adjust to getting it to run true to your saddle and bed.

Start at the tailstock end, engage the half nuts, insert screws and tighten up the leadscrew block. Release half nuts, go as far as you can towards the headstock, slacken off the bolts holding the gear train to machine, engage the half nuts, tighten up the loosened screws.

Repeat once more at both ends, and you should find the leadscrew will be centralised as good as you are ever going to get it. You might need to shim up the blocks if it pulls towards the casting, but the way it is made, there is plenty of adjustment built into these machines to get you out of trouble.

With a little work, these machines can be turned into very accurate and robust machines for very little extra outlay, and if ever I had the requirement for one, I would have no qualms about buying one and giving it a good dose of looking at, just as you are doing.

John

 

[cfellows]

Here's a drawing of my tangential tool sharpening jig. The only critical dimension is the 60 degree angle.

Chuck

 

[RollaJohn]

Chuck

I am interested in your Wilton keyless chuck with the Morse Taper arbor. How is it working out for you?

I just looked at your eBay seller's listing and it is still available. It has come down in price to $29.99 with free shipping but I see that you evidently are the only person who has purchased the item. At least the seller claims to have sold only one.

So it is up to you to let us know: Is this a good item or should we save our money for something better? You have the power!!

 

[cfellows]

Well, the Wilton chuck hasn't seen a lot of use, but it seems very well made. The action is tight but smooth and easy. I thought it was a good buy at $60+. At $29 it seems like a screamin' deal!

Chuck

 

[Omnimill]

Thx, Tin. The apron gear cover is on the list of things to do.

Thx, Bob. This minilathe is almost like a candy store with the number of mods and improvements that are shared on the WEB. I might spend the rest of my machining career tricking out this minilathe! :big:

Thx, TWMaster. Appreciate the comments.

Here are some pictures of the jig I made for grinding tool bits for the tangential holder. It's made from a hunk of aluminum to help conduct heat away from the tool bit. I use the jig with my 2" x 48" vertical belt sander. Cuts fast and relatively cool.

Chuck

Chuck, what angle have you used for your grinding jig?

Vic.

Update, Oops sorry just seen the plan!

 

[cfellows]

Well, I think I'm now an official hoarder of projects. I ordered a 14" mini-lathe bed conversion kit from LMS and it arrived via UPS a few days ago. Tonight I tore down the 10" version and will now reassemble with the new bed. I was pleased to discover that the saddle fit the ways on the new bed perfectly with no adjustment to the gibs. How lucky was that! On the other hand, the long vertical slots for the motor mounting studs are completely missing. May have to look at an alternative motor mount. Might consider putting in an intermediate jackshaft for more high / low control. We'll see.

Has anyone else completed this conversion?

Chuck

 

[winklmj]

On the other hand, the long vertical slots for the motor mounting studs are completely missing.

If you dont' go the jack-shaft route, there's some info on the web about using a heavy-duty gate-hinge for a pivoting motor mount.

 

[cfellows]

I followed up on the gate hinge idea and determined how the original motor mount is supposed to work. So I spent an hour or two coming up with my own version using a door hinge:

After finishing it up I decided to go ahead and mount the rack. I opened up the big plastic bag that came with the lathe bed conversion kit and, guess what, they had included a motor mount that goes with the 14" bed! And here it is, affixed to the motor.

So a couple of wasted hours, but problem solved in a much more elegant manner. Guess I should have checked the contents of the kit more closely before starting, but what fun would that be!

Chuck

 

[Blogwitch]

I've done my fair share of trash can diving after inadvertently throwing away supplied bits.

But I still do it, rip the packaging apart before first getting out and reading the destructions.

This looks like it is really going to improve your little mini lathe.


John

 

[cfellows]

Thx for dropping in, Bogs. I'm not really sure why I'm fussing with this mini lathe. I have an 11" Logan which is in good shape and will do pretty much anything I ask of it. However, I have already found that having a second lathe set up can come in handy when you don't want to disturb the set up on the other lathe for some reason. Also, if I have to downsize my shop even more as I get older, I would like a decent smaller lathe. I've ordered the metal high / low gear and the tapered roller bearing set for the spindle. After I get those installed I think it will be in pretty good shape, except for some other add-ons like a carriage lock, carriage stop, etc.

Chuck

 

[Blogwitch]

Chuck,

After I had finished Darren's lathe, I couldn't, in all honesty, believe how good it ended up, and I am sure yours will end up just as good, if not better.

If I hadn't have just picked up the Pultra to refurbish, I was considering buying a smaller lathe, purely because of the reasons you mentioned, and it would have been a mini lathe. With a bit of care, they can turn out to be an outstanding bit of kit.


John

 

[kc5ezc]

Chuck: I bought a HF mini-lathe 6 years ago. Found it to be a little short in the bed area, so ordered the 12 inch mod from LMS. The 14 inch did not exist or I would have got it. Then bought a 13x40 from Wholesale tools. The mini-lathe is a work in progress; always something that I can do to improve it a little bit. The WT lathe hasn't had to have any mods to it. I really enjoy having the two lathes. The mini-lathe is great for the small stuff and the larger one takes care of the big, tough stuff. Big to me anyway. Thanks for the tapered gibs write-up. That is next.
John Burchett
in Byng OK

 

[rcmadness]

I started with the 7 x 10 myself about 10 yrs ago. It has served me well. I bought the 10 x 22 over the summer and bigger is nicer but I still have my 7x10 setting next to it. I use it mostly for quick cuts and polishing. The variable speed is what draws me to it, when I want to buff something out I have a buffing wheel that chucks up and a plastic bed cover that makes it a great too to spin up the buffing wheel. I doubt I will do any more mods to it, I am now tinkering with the big lathe.

Your gib makeover is great and I actually thought about trying it on mine. That is the one thing that bugs me about Chinese equipment is the fact I cannot keep things tight on anything Chinese I own. Lathes, mill, drill presses etc, everything tends to loosen up quickly.

I headed down to ace hardware tomorrow to find some american made 6 mm set screws to replace all the set screws in my Chinese tool holders. I stripped another one out tonight.

 

[cfellows]

Thanks for the comments guys. I've had a bunch of projects underway lately and haven't felt like any of them will ever get finished. However, today I am nearly finished with the list of outstanding mods to the mini lathe. I am (mostly) finished with the 14" bed conversion. I still have to drill and tap a few screws that hold guards and covers on. I also have to drill and tap the hole for the change gear banjo, but there's no hurry on that since I doubt I'll be doing threading any time soon.

I also replaced the plastic speed change gear on the spindle with a metal one. I left the intermediate plastic speed change gear installed so the lathe would run quieter, and, if something is going to fail, I'd rather it was the intermediate gear and not the spindle gear.

Finally, I replaced the spindle ball bearings with tapered roller bearings. After getting it all back together, I found a plastic spacer lying on the workbench that belongs on the spindle inside the headstock. That's it sitting on top of the headstock casting. Its purpose is to keep the spindle speed change gear positioned properly. Oh, well, tomorrow I'll get the spacer put back in its proper place, then the new spindle bearing job will be completely finished. The spindle rotation is very smooth and the total inidicated run out eight inches out from the chuck is about .001". At this point, I'm very happy with the outcome of all these changes.

Unfortunately, I didn't photogaph any of the process, but will answer questions for anyone thinking about the same conversion.

Chuck

 

[cfellows]

This is a crank I made for the leadscrew on my 7 x 14. I didn't want to modify the leadscrew, so I mounted the crank on the left side of the leadscrew. I made the crank from 1/4" thick aluminum and attached it to a 42 tooth browning timing pulley.

At some point, I will lash up a DC gear motor connected with a removable timing belt so I can also have a variable speed carriage feed. I don't expect, at this point to use the change gears very often, although I can easily remove the crank and revert to the change gears if need be.

In this picture, you can see a steel ring which was heat shrunk on to the hub of the gear. This will be engraved with graduations and numbers for a fine feed measurement.

Chuck

 

[Maryak]

Neat Idea Chuck :bow: :bow:

Best Regards
Bob

 

[cfellows]

Added another tool holder to my mini lathe QCTP. This one holds 3/8" shank boring bars.

Chuck