# New Mill... Broken Gib



## centech (Feb 8, 2016)

Hello... I'm a brand new member with a brand new King 942VS-6-NS5 Bridgeport style milling machine... and she has a problem.

A little back story: I was retiring in May of 2014 (39 years in law enforcement) and as a retirement gift, my son bought me a new King 14"x40" lathe from a local dealer, here in Winnipeg, Manitoba, Canada. The company was closing its doors after 80 years of business and they heavily discounted their remaining stock. We snapped up the lathe at dealer cost, 3 weeks before they were to hold a public auction on the remaining inventory. They also had the above mentioned milling machine for sale, complete with power feed on the X axis, an X/Y DRO, some tooling and a decent 8" vise. It retailed for $13,500.00 CDN and had been marked down to $10,999.00 CDN but I opted to wait until the auction to bid on the mill. Three weeks later I won the mill in the auction. I'd known the owner and the staff for the past 40 years and they assured me that the mill would be covered by a 1 year warranty even though they sold it through the auction.

Shortly after the mill was delivered to my shop, I began cleaning off the packing/shipping grease in preparation for setting it up in its new home. As I raised the knee it began to bind and became tighter and tighter as I tried to lower it. It would only go up, quietly stiffly I might add, but refused to go down. I heard a "tinkle" sound and discovered a piece of the knee's gib laying on the base. The bottom inch or so of the gib had broken off and fallen out of the dovetailed way.

I called the dealer who was still in the process of winding down the business and they said to call the local warranty centre. The warranty centre directed me to King Canada in Québec and a long, back and forth exercise began. They initially began to honour the warranty and eventually abandoned me claiming that since the mill was purchased at auction they wouldn't honour the warranty. Eventually they agreed to send me new parts and I received a new gib that was completely incorrect for the machine. The gib is too thick; too long and the side angles are 52 degrees whereas the original gib's side angles are 50 degrees.

They followed up 5 months later with a gib that's closer to the original but still not the correct size. The second gib is too long and the oiling holes and journals are in the wrong location. The angles are correct and my original gib dimensions can be duplicated by cutting some material away from the top and bottom of the replacement. However, the oiling holes/journals would be in the wrong location and the entire new gib would require scraping and fitting into the dovetailed way.

Should I silver solder or braze weld the broken piece to the original gib or would time be better spent modifying the replacement gib? I have the skills and equipment to weld on the broken piece and I'm thinking that I'd only have to scrap and fit the area of the weldment vs re-machining the oil holes/journal and scraping and fitting the replacement gib. Fitting, adjusting and installing either gib is something new to me.

I welcome all your thoughts, suggestions and recommendations. 

Cheers
Mike
(sorry for the longish post...)


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## Bob Korves (Feb 8, 2016)

Gibs need to be scraped in to fit regardless of what you might find in a new import lathe.  Welding or brazing the old gib is acceptable, but it needs to be straight and in register or the gib will be too small by the time it is fitted.  You can make the replacement gibs work by fitting and scraping them for good overall contact or make a new gib from scratch.  You are not likely to get a new gib that is plug and play, they all need to be fitted.  My guess is that your mill left the factory with a broken gib, or so poorly fitted that it broke from the point loading strains put on it.


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## centech (Feb 9, 2016)

Thanks Bob. I recently bought a Sandvik carbide scraper and Dykem HiSpot Blue and have been practicing scraping random stuff in my shop. After reading and viewing many vids I've learned the secrets to successful scraping... patience and practice, practice, practice! Actually, it isn't very difficult and I find it rather soothing work. 

The new gib, that can be made to fit my mill, has a slight bow in it... maybe .040 or so over a 20" length. I'm not sure what material/process is used in making a gib but from the look of my broken one, it appears to be either cast steel or cast iron. Would you know if there's a common material/process used in making Chinese machinery gibs and how much bending can it withstand when straightening?


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## Bob Korves (Feb 9, 2016)

If it looks cast, it is probably cast iron, which is common for gibs.  It is good that you have been practicing scraping, because you are going to need it.  Do you have the book "Machine Tool Reconditioning" by Edward Connelly?  It is the bible for that kind of work.  Paper copies are now $90-100, but there is a free download available:
http://totallyscrewedmachineshop.com/documents/MachineTool-Reconditioning.pdf
It is a very long read, but it contains the information you are looking for.  Scraping in a gib, especially a tapered gib, and even more so a double tapered gib, and doing it correctly, is not trivial and you need to understand how to approach the job.

They sent you a .040" warped gib as a repair part?  What nerve...  You will probably break a cast iron gib if you try to bend it.  Don't go there.  If there is enough material you can machine it flat before you scrape it, if it will still fit the space afterwards.  That might make it too thin to work (don't know what type of gib you have).  After machining, scrape it in.


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## centech (Feb 11, 2016)

Great link, Bob. I've read most of it and I'll download a copy for future reference.

I had removed the broken gib by raising the knee using channel iron, wooden cribbing and a hydraulic jack, while the knee and table were supported by my gantry crane. The gib traveled up along with the knee and I was able to drill/tap a hole into the top edge of the gib. I installed a bolt and used the bolt head to lever the gib out through the top of the ways. The threaded shaft that raises the knee is completely clear of the brass nut and the whole knee assembly is hanging from the crane with a few inches of the knee's dovetail still indexed within the dovetail of the base. The threaded shaft is resting lightly on a block of wood atop the strut into which the nut is bolted. Am I dreaming in thinking that I can fit and install the gib without disassembling and removing the knee?

I've seen YouTube videos where old Bridgeport mills were rebuilt and they were completely stripped down during the process. I'd rather not disassemble/remove the table but I have this sinking feeling that it will have to come off.  I'm not looking forward to it but, I have this notion that I should remove the head, strip and remove the table and lay the naked base column on its back in order to fit the gib to the dovetails. Do you think that's the only way to do the job successfully? Should I try to fit the gib to the unit as it currently stands, or is that a fool's errand? I'd be working on my knees while under the knee/table. It's well supported so I'm not too concerned that safety would be an issue.

Winnipeg's a fairly big city... population of about 750,000, but unfortunately I don't know anyone in the trade from whom to seek help. So... it's all on me.

I appreciate your thought and suggestions.

Mike


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## JR49 (Feb 11, 2016)

centech said:


> I don't know anyone in the trade from whom to seek help. So... it's all on me.



I feel your pain, Mike, I too, don't know anyone in the machine trade. Mt friends politely listen, when I talk about my new hobby, but, shortly, I see there eyes glassing over, so I stop.  That's why I feel so blessed, having found this forum.  Good luck with that gib,  JR49


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## centech (Feb 11, 2016)

Thanks for your words of support JR. In all my lifetime I don't ever remember failing... err, the 2nd time... or maybe it was the 5th time? 10th time maybe??? (lol) 

Actually... I've screwed up many things but I'm a "stick-at-it" kinda guy and eventually I get it right. I think most people could be successful at things if they just kept trying (providing you learn from each mistake and improve/change your approach). I think most people who pursue the precision inherent to the machining arts are "stick-at-it" people.

I've been very happy with the build quality of my King lathe and I've read many positive online reviews about the King brand and Chinese machines in general, so I think this mill just happens to be the odd lemon that every manufacturer occasionally produces. What really sucks is the lack of service support from King Canada.

Since the original gib appears to have been factory tuned with an angle grinder, I'll probably tear down this brand new mill to see what other horrors may be hidden within!


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