# Mini-Lathe fun



## Grimm (Oct 5, 2009)

I have been working on my lathe (a Grizzly 7X12) getting it up to speed and working out the kinks. I also was thinking that other people with these Chinese lathes would like to see the modifications. Hey, if I can do it, anyone can, really.







The three things I most wanted to do was:

1) Clean up and lap all the gibs and tighten everything up.
2) Tapered gibs for the saddle (no more having to remove the saddle to adjust the gibs, yay!).
3) A saddle lock (the lathe didn't come with one).

I purchased the bar stock for the tapered gibs and machined them on my mini-mill following Rick Kruger's plans I found online. 


http://warhammer.mcc.virginia.edu/t...addleGibs/ 

I didn't make a jig but instead followed Bog Standard's method of super-glueing a pin on one side of the bracket to get the needed taper for the gib. You can follow the mod here:


http://madmodder.net/index.php?topic=627.30 

The other change I did was to not use the adjusting screw like both Rick and Bogs use. Instead I wanted to follow more of the same kind of setup that you see on larger lathes, where the gib is held in place by a screw on each end. So I drilled two holes on either end of the gib brackets and made four "L" shaped brackets to hold the gibs in place. Here is a pic of one side of the front gib:











So far they have worked really well, the saddle is rock solid but can still move back and forth easily. The only problems I had in the construction was the lathe bed was slightly thicker on the back at the end and I was not able to remove the saddle with the back gib tightened up. I held a file up under the bed and filed a little off and the saddle now comes off with no binding. It must have been really close, I have noticed that the later versions of these machines are made to much tighter tolerances. The other problem was that I broke the tap off on the last hole I was tapping.







Luckily for me, the university shop guys had a tap extractor and I was saved! 

The other thing I wanted to make was a saddle lock, locking the lead screw was just not working out very well. Here is the work so far, I need to remake the adjustment screw because I might be able to keep a tap straight, but I can not keep a die straight at all. I purchased a die holder from LMS so hopefully my die sadness will go away. Here is a picture of what I have finished so far:










I have drilled and tapped the holes in the saddle for the lock, all I need now is a round die to cut the threads on the new adjustment screw. I lapped everything and put it back together, so I had to try it out and see how well it works now. Very nice, I definitely recommend the tapered gib conversion, it's a must on these lathes. One of the tests I did was to face and clean up some old wrought iron (a 1.5" diameter bar) I have that is from the 1870's. I had to cut into the metal pretty deep to get past the corrosion (about 1/16"). I used a little oil and it cut almost like brass. Very cool. Here are some pics:




















Not bad for 120+ year old metal, eh? I was thinking I would like to use some of this material in my engines, maybe something not critical to the operation of the engine?









Jason


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## SE18 (Feb 21, 2008)

Pretty neat regarding the wrought iron. I have read that it keeps a long time and is easier to work than iron made today. Isn't it also supposed to have a grain like wood?


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## xo18thfa (Jan 2, 2008)

Nice mods Jason. MadModder is a great website. Another is HMEM.

http://madmodder.net/ 

http://www.homemodelenginemachinist.com/index.php


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## Pete Chimney (Jan 12, 2008)

As a geologist I find the table top your wrought iron is sitting on to be or more interest to me. This is a nice example of a fractured, brecciated dark (organic rich ?) limestone with some good white calcite vein fill.


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## Grimm (Oct 5, 2009)

SE18 - Yep, it's hard to see on the first picture, but on the second one you can see dark vertical lines, those are from stringers of silicates in the metal. These silicates help to retard corrosion, modern steels have much less slag and other impurities in them. Here is a picture of a wrought iron bar that was cut partially through and then slowly bent to revel the grain. 











A lot of people like to use old wrought iron in a decorative fashion where they will polish and then etch the metal to bring out the grain. Fun stuff.

Bob - Thanks!







Those sites are very cool. I know where I will be spending some of my free time.

Pete - Thanks, it's just a floor tile a friend gave me. I'm using it as a cheap surface block. 

Here is a picture of the saddle lock in place and working. Now I can start thinking of doing a steam project.


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## SE18 (Feb 21, 2008)

Thanks. The photo of the grains is great! Today, what's called wrought iron mostly isn't. You've got the real deal there and the project looks pretty neat. 

Dave


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## Greg Elmassian (Jan 3, 2008)

Know as Emperador Dark marble, not limestone (although most marble used to be limestone)... Greg Posted By Pete Chimney on 10 Feb 2011 11:38 AM 
As a geologist I find the table top your wrought iron is sitting on to be or more interest to me. This is a nice example of a fractured, brecciated dark (organic rich ?) limestone with some good white calcite vein fill.


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