Mini-mill in my future?

[DavidR8]

Ok folks here's my lathe.
Overall it looks pretty good. It's very smooth and quiet when running. Power feed works well, Half nuts engage and disengage positively.
In the crate there was a loose allen bolt 1/2" long. No idea where it's from at this point.




Is this typical for the crossslide crank to not have a zero ring? (I have no idea what it's actually called but the ring that rotates to mark zero so you can tell how much you're advancing the slide)

I noticed an oil port on the chuck which seems a good idea.


There a casting flaw on the bed but I don't think it will affect anything. Overall the machining on the ways is quite good. Tailstock slides very smoothly. Gibs on the crossslide and compound need some attention.

The detent for the forward/reverse is slightly off such that when in neutral, the top plastic gear makes slight contact with the spindle gear. Actually the contact is intermittent so I think the spindle gear is actually not quite round. Hmmm....

The only other thing I noticed when running it is that the arm at the bottom of the gear box is misaligned causing the gears to run slightly askew. I think the nut at the bottom is too thick.

 

[DavidR8]

I pulled off the gear cover tonight to look at the misaligned change gears.
The change gear plate is flat.


I think the problem is that the pivot for the change gear adjustment plate is not perpendicular to the plate so when the adjustment nut is snugged down it skews the plate.


The location of the pivot on the base is not machined flat, it's just rough cast iron. If the pivot isn't tightened down the plate is flat. My hand is holding the plate up so the gears mesh.


I think I can hit the base with a grinder and get the spot where the pivot sits closer to flat. Barring that I might have to shim it out. Shimming it perpendicular seems a bit cheesy so happy to hear other views on how to improve.

 

[Aaron_W]

Congratulations on the new addiction machine.


These 7x14 lathes are somewhat notorious for needing a little massaging to get them running well, but they seem to do a good job once that is done. There are tons of youtube videos on recommended tweaks, as well as groups based around them. Replacement gears seem to be a popular upgrade. There was a 7x14 Yahoo group with a lot of information, but Yahoo groups will disappear forever in a few hours.

There is a mini-machine Sherline, Taig, Sieg etc section under brand specific machines area, in addition to this mini-machine part of the site.
Sherline seems to dominate most of the discussion in the brand forum, but there are posts about the Sieg machines. Most of the 7x14s are made by or at least based on the Sieg lathes. The factory makes machines for many re-sellers the main difference being the color and branding on the individual machines.


Just a suggestion, but if you are asking a how to question that is not specific to your machine, I would post in the beginners or general area as they are more widely viewed and will get more responses. Other than size / power there isn't a whole lot of difference in how a 20x96" Monarch does something and how your 7x14 does it, just how quickly it gets done.

The mini-machine and brand specific areas are best for when the question pertains specifically to the machine. Don't feel like having a small lathe restricts you to the mini-machine areas of the forum.

 

[francist]

The thing with shimming is that although it may not be a perfect long-term solution it does tend to be reversible. If there’s a chance you’ve misdiagnosed the problem / solution, a shim can usually be undone without much grief. I’m not quite sure how the nuts come into play though — if you did shim it, would it be something that would need to be redone each time you changed the position of the banjo?

Another possibility is adding a thin washer backed with some JB Weld to create a new boss that would be square to the casting and not skew the pivot. This would stand the pivot off the casting more though, so it might not be an option without some judicious grinding first. I don’t know just from looking at the photos how much room you have to work with.

A final caution if you do decide to employ a grinder — cast iron can yield surprisingly quickly under the wheel and it’s really easy to go way deep way fast! Employ care, and a small grinder if possible unless you’re a good hand at it.

- frank

 

[Jidis]

There was a 7x14 Yahoo group with a lot of information, but Yahoo groups will disappear forever in a few hours.

Not sure if there was a 14, but if you're thinking of the 7x12 group, that activity got moved to groups.io a while back for anybody interested in joining it. 7x12 is just the name. I think any mini lathe discussion is welcome.

7x12MiniLathe@groups.io | Topics

groups.io

 

[DavidR8]

The thing with shimming is that although it may not be a perfect long-term solution it does tend to be reversible. If there’s a chance you’ve misdiagnosed the problem / solution, a shim can usually be undone without much grief. I’m not quite sure how the nuts come into play though — if you did shim it, would it be something that would need to be redone each time you changed the position of the banjo?

Another possibility is adding a thin washer backed with some JB Weld to create a new boss that would be square to the casting and not skew the pivot. This would stand the pivot off the casting more though, so it might not be an option without some judicious grinding first. I don’t know just from looking at the photos how much room you have to work with.

A final caution if you do decide to employ a grinder — cast iron can yield surprisingly quickly under the wheel and it’s really easy to go way deep way fast! Employ care, and a small grinder if possible unless you’re a good hand at it.

- frank

Thanks for the advice Frank, well taken.
I'm not sure that I described the situation well. The stud which provides the attachment point for tightening the plate is like a stud with a nut in the middle of the length.
It is threaded into the base till the nut part seats against the cast iron. That's where I'd be looking to shim it out so that the stud is perpendicular to the change gear plate.

This isn't my lathe but the offending stud can be seen through the adjustment slot in the change gear plate.
In my case, the stud is canted to the right a few degrees.

 

[francist]

Right, that’s sort of what I was anticipating. In use, you loosen only the outside nut to adjust the banjo for different gear configurations and the nut that holds the pivot solid to the casting (almost like a jam nut) remains unchanged. Where I was going with all of that was trying to figure whether a shim would be a one-time fit and not have to be re-fiddled each time you loosened the outside nut.

-frank

 

[DavidR8]

@francist I think it's one-time fit because as you say, only the outside nut is loosened to change to position of the plate.

 

[DavidR8]

I sorted out the change gear problem today.

Here's what I started out with:


I shimmed out the stud with two layers of copper strapping.


Here's the result.


That makes me very happy!

 

[mickri]

After reading through all of Mikeys tool bit thread several times when I was looking for info on how to grind certain tool bits I made a list of where to find each type of tool bit. I posted that list on page 34 post 1007.
Being a newbie at this whole machining thing with limited funds I first used my 4" handheld high speed grinder to try to grind tool bits. That took lots of trial and error to even get close and never worked very well. Then I found a 6" dunlap bench grinder at a garage sale. That was a big improvement over the grinder but still left much to be desired due to the lack of a good support. I then found an old Delta 1x42 belt sander in a thrift store. Wow is all I can say. Grinding the exact tool bit angles that I wanted was now a piece of cake. You will eventually want a bench grinder but I would get a belt sander first. The really important think to look for in a belt sander is a solid platen that doesn't move or flex. The size is secondary to the platen.

Have fun with your new lathe.