mini lathe cross slide gibs

[vph]

Hi,

did somebody try making the gibs out of acetal or derlin? Is it possible at all?

I just got a used mini lathe 7x12 and want to replace the gibs. I have only a small cnc router where I can machine brass at most. Because there are a lot of acetal or derlin bearings in use I was thinking is it not possible to make the dovetail gibs from such plastic.

Thanks,
vph

 

[Andy]

My 7x14 still has the original ones in, but if I was replacing I'd use brass. I may be wrong, but I don't think you'd get good performance from delrin or similar. These things need all the help they can get regarding rigidity. :-[

 

[steamer]

I'd say way better off with mild steel or iron. Plastics will creep...and will be no where near as stiff.

Dave

 

[gunboatbay]

This reply doesn't exactly answer VPH's question, but is something to consider. The experts' (not me) recommend that gibs be made from cast iron because of its stiffness and integral lubricant. However they must be made from 'seasoned' cast iron, otherwise they will warp after machining. The warping aspect is a major problem with many Chicom machines as the gibs are made from 'green' cast iron and warp well after the machine is tested and crated for shipment. Trying to adjust a warped gib is a hair-pulling experience (ask me how I know).

 

[websterz]

The gib arrangement on the 7x lathes sucks. Put tapered gibs on it and eliminate all your problems.

 

[vph]

Thank you all for responding to my question.
Meanwhile I managed to straighten them and is much better then before. But still just knowing how they are build is disturbing.

Did indeed somebody replace them with tapered gibs? Can somebody post here pictures, drawings or links?

vph

 

[Tin Falcon]

It has been done
http://www.homemodelenginemachinist.com/index.php?topic=9016.0
Tin

 

[Dunc]

If you can obtain Model Engineers' Workshop magazine (http://www.model-engineer.co.uk/), Dave Fenner authored a multi-part article on many modifications to this lathe. It started in the Holiday (Christmas) 2007 issue and ended in Dec 2008.

Specifically, Part 13 of the series, Issue # 145, Dec 2008 offers three options to deal with saddle adjustment/new gib fabrication.

Most of Fenner's articles are included in his book, The Mini-Lathe. It is #43 of the Workshop Practice Series, ISBN 978-185486-254-9. The saddle adjustment article is, unfortunately, not included.

 

[steamer]

Any good grade of durabar stock will work just fine as a gib. My scraping masters are made of it, and though they are big and easily disturbed if bumped, they come back if given time to "rest".

I have more problems with the heat from my hands actually.

For a gib, you should be fine.

Dave

 

[Dunc]

The latest Arc Euro Trade catalog (#7) lists "Brass Gibs Set" for the C3 Mini-Lathe.
Part # is C3-BRASS-GIBS; cost is 15 British Pounds.

Website is www.arceurotrade.co.uk

I have not used them.

Usual disclaimers apply.

 

[rich9959]

The original are .202" x .202" and they twist under load.
If you have a mill make the gibs out of steel. There .132" x .132" face to face at 60 deg. After they are made lightly polish them. You want to leave light tool marks to hold the oil.

 

[zoltan]

Little Machine Shop sells brass gibs for the mini lathe cross slide and compound:
http://www.littlemachineshop.com/products/product_view.php?ProductID=3843&category=

 

[Tin Falcon]

Lots of good comments on this thread.
So we have a :
1)US , and Europe source to buy brass gibs.
2) a link to make a taper gib system.
3) recommended material a) cast iron durabar, b) brass, c) Steel.

I have yet to upgrade mine probably because I have other lathes to use.
But is did make brass gibs for the x-2 mill and they are a vast improvement over the factory ones.
For those you want to make there own there is a vise /jig to make the job easier. Gib strip vise block from fignoggle .com the link is to the plans.

Rich please post an introduction in the welcome area tell us a bit about yourself , your shop, your interest in model engines and your location.

Tin

 

[bazmak]

Hi,i have just made new gibs from brass for the cross and compound slide
I setup my cheap belt sander and ground the the two angle faces
Worked realy well,good finish and accurate to 2 thou.I made them
to a few thou under max size so there is min adjustment from the screws
and i added additional screws see my thread and photos its made a massive
improvement. Regards barry

 

[nrml76]

Apologies for resurrecting an old thread, but this information will probably be useful for people researching replacement brass gibs for mini lathes and is therefore best attached to this thread. The off the shelf replacement brass gibs supplied by a UK dealer for Seig mini lathes is not a drop in replacement on Real Bull mini lathes. I would imagine the same would apply to those supplied by the US dealer as well.

I cannot fault the quality of the brass gibs supplied to me or the customer support provided, but they don't fit on Real Bull version (or at least they didn't fit mine). The cross slide gib was too small and twisted in the gap while the top slide gib was too big to fit in and needed to be machined down.

 

[zoltan]

I finally got around to modifying my lathe gibs the same as my mill gibs. I basically milled flat pockets for the set screws to seat against in the stock gibs. This keeps the gib at a 60 degree angle for optimal contact with the dovetail. I also added two extra set screws on both the compound and cross slide. I reassembled everything with a generous amount of Mobil Vactra on the ways and gibs. The difference is AMAZING. There is virtually no play, but I can still move the compound and cross slide easily and smoothly. Seriously, forget brass or Delrin, this way is easier, faster, and cheaper (if you have a mill) and works really well.

Write up on my blog: http://benchtopmachineshop.blogspot.com/2015/01/lathe-gibs.html

 

[velocette]

Hi
This is a query that has popped up before and from my previous reply.

"Is it Possible to replace the setscrews with some of those set screws that have a ball bearing in the tip."

Yes a "Loose" ball bearing at the end of the set screws are an improvement I can recommend Looks like I< o >= I being the gib and = being the screw.

The set screw and lock nut is primitive but is very effective been in use for over one hundred years.

The secret of setting up is in the "feel" Use the allen key with the long leg in the screw and tighten it until it is finger tight firm only then hold it firm and tighten the Locknut making sure that the setscrew does not turn.

Checking the adjustment by moving the table with the hand wheel. Repeat this on each screw. It is all in the "Feel" of the tools and hand wheel.

I did a similar project with and X2 mill Drill that made it much more user friendly.

Add a small tip. Use "Cup Point" grub screws for gib adjustment and a "Ball Bearing" that is "Tapping Size" for the Gib Screw I.E 6 mm thread 5 mm ball bearing.

You may have to use a hand drill to tidy up the dimples in the gib as sometimes the finish on some X2 mills.
leaves a lot to be desired.

This leaves dismantle and a tidy up a necessity.

Some users advocate using a brass on bronze gibs.

Enjoy

Eric

 

[ShopShoe]

If you want to start slowly, you can also lap them.

see:

http://www.mini-lathe.com/Lapping/Lapping.htm

--ShopShoe