New G9729 - Some early issues.

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Diesel Gypsy
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Re: New G9729 - Some early issues.

Post by Diesel Gypsy »

The saga continues , , ,

I pulled the cross slide off again and this time I used guage pins to measure the carriage with the gib installed. Again, 18 thou taper.
So I measured the gib and got .054 total taper.
Then I measured the cross slide and got .072 total taper, which is a difference of .018 :roll:

I talked to Grizzly again and they said they don't have the specs for the tapers so they are going to send me a new carriage and gib on warranty so I hope that will fix everything. Everyone seemed to think that Grizzly is great for standing behind their products and so far I have to agree.

The cheaper way would have been to just send a new gib and try that first but I really didn't want to wait for 2 weeks for a new gib to arrive and then find out that it is the saddle that is ground wrong and then have to wait for another 2 weeks to get a new saddle. But it wasn't an issue at all. The Grizzly rep said immediately that they would just send both parts right away!

By the way, Grizzly ships everything through UPS and UPS sucks in Canada which is where I am, so it always seems to take 2 weeks to get anything
Anyhow, thanks to everyone for the help and now I guess I'll have to wait for a while.
Torch
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Location: Muskoka

Re: New G9729 - Some early issues.

Post by Torch »

Somewhere out there, a sister to your machine has a gib with a .072" taper and a table with a .052" taper...

Someone on this board once said "When you buy a Chinese lathe, you are buying a lathe kit." There is some truth to that. Glad to hear Grizzly is working with you to sort it out though.
Diesel Gypsy
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Re: New G9729 - Some early issues.

Post by Diesel Gypsy »

Torch wrote: Tue Mar 16, 2021 1:22 pm Somewhere out there, a sister to your machine has a gib with a .072" taper and a table with a .052" taper...
Lol, I was thinking that too!
Torch wrote: Tue Mar 16, 2021 1:22 pm Someone on this board once said "When you buy a Chinese lathe, you are buying a lathe kit." There is some truth to that. Glad to hear Grizzly is working with you to sort it out though.
I believe that the Chinese build some top notch, high quality stuff. But we don't buy that stuff cause we're CHEAP and so we buy the low end stuff and then complain about the quality! Lol.
Overall I've been very impressed with the level of quality that they have supplied in this lathe for the price that I paid for it. Nothing is perfect but that's why there is a warranty. Often though the warranties of cheaper products is worthless. It's nice to find that Grizzly stands behind their warranty.
The worst part is the waiting! Oh well . . .
Torch
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Re: New G9729 - Some early issues.

Post by Torch »

Yes, the Chinese can make some decent stuff if they want to. They even have rocket scientists over there. But I have it on good authourity that there is a certain cultural cache to pulling a fast one on a "gwailou".

My understanding is that Grizzly is buying from the same factory as everyone else (design and parts are generally interchangeable, anyway) , but they have their own inspectors over there to enforce quality control standards. They also write their own manuals, in understandable English, and usually avoid mistakes like the one above.
toddalin
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Re: New G9729 - Some early issues.

Post by toddalin »

Diesel Gypsy wrote: Tue Mar 16, 2021 11:13 pm
Torch wrote: Tue Mar 16, 2021 1:22 pm Somewhere out there, a sister to your machine has a gib with a .072" taper and a table with a .052" taper...
Lol, I was thinking that too!
Torch wrote: Tue Mar 16, 2021 1:22 pm Someone on this board once said "When you buy a Chinese lathe, you are buying a lathe kit." There is some truth to that. Glad to hear Grizzly is working with you to sort it out though.
I believe that the Chinese build some top notch, high quality stuff. But we don't buy that stuff cause we're CHEAP and so we buy the low end stuff and then complain about the quality! Lol.

Can't agree with this. Of the 3-in-1s, ShopTask is among the highest rated and most expensive ($5K) and you would be hard pressed to find a better Chinese, mass production 3-in-1. But, in the factory with beaucoup parts available they try one and if it fits/works fine. In not, they will find another that will..., eventually.

Now when you go to replace it, you don't have the luxury of selecting between all of those "almost fits" to find the one that really does. BTDT.
pete
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Re: New G9729 - Some early issues.

Post by pete »

Ideally you'd want to check that new gib for straightness on a known flat surface like a surface plate. And I'd expect it will probably need some light stoning to remove any burrs.Obviously having a perfectly straight gib would be best, but they can still work with a few thou curve in them if it's not too severe. And it's bearing area and fit needs to be checked against the tapers within the two pieces of the slide. Normally something like Canode or high spot bearing blue would be used for that. It can still be done almost as well by just coloring the whole face of the tapered gib with a black felt tipped marker, assembling all the pieces to there properly adjusted position without any oil and then moving the slide over it's full travel. Disassemble and you can then read how well the gib fits and bears against the dovetail. Where the high spots are the black will be scraped off. That may or may not be good news. Tapered gibs are pretty touchy for there exact taper angle, width and length to stay within the limited adjustment length of the opposing adjustment screws.

Doing selective hand fitting of parts like this until you find something that works at the factory during assembly still seems like a strange way to run any production line though. Interchangeable parts by properly controlling the manufacturing tolerances was one of the reasons that idea was invented. It's actually a lot cheaper and faster to do it that way.
Diesel Gypsy
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Re: New G9729 - Some early issues.

Post by Diesel Gypsy »

toddalin, I was referring to Chinese made quality equipment, not just 3 in 1s. Any 3 in 1 machine is already a compromise usually made to be cheaper than 2 (or 3) stand alone machines and so we are not talking about high quality here no matter what name is on it. Some are better than others for sure but none are the quality of most German made machines but the Germans won't come anywhere near the selling price of the Chinese machines.
The Chinese make some very high quality equipment but if you priced them out you would find that the price would be right up there with any other high quality machinery and that is why most of that stuff stays in China because they can make a lot more money selling lower quality stuff to us cheapskates!
I include myself in the cheapskate class because I was willing to compromise quality for an affordable price. I am not earning my living with this lathe, it is just a hobby for me so there was no way I could justify buying top end equipment. So I'm quite happy going through some issues because it's all a learning process and this sort of thing is helping me to know this little lathe intimately, building confidence in my ability to overcome problems!

Pete, I'm a ways away from getting out the blue for the carriage dovetails. The gib is very straight and so are dovetails on the carriage and the cross slide. It's just that the bevel is cut wrong on either the gib or the carriage. I'm pretty sure that they would run the same bevel angle on all these machines so I think this was just a fluke and I'm betting that it's just the gib that is wrong but Grizzly is sending me both parts so we will see.

I believe that the gib is ground longer and then fitted to get the right clearance and then the ends are broken off at the right length and a notch cut in for the adjuster. What makes me think this is the ends of the gib are jagged like it used to be longer and they just took a piece out of the middle by snapping off the excess. It's cast iron so it would snap off easily. Just my theory and I'm hoping that the guy just happened to grab a tapered gib for a different machine (with a different bevel angle) by mistake and put it in my lathe.

We've all heard horror stories of the screwups in American car assembly lines so let's not be too hard on the Chinese. As long as they are willing to make it right I won't hold it against them!
toddalin
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Re: New G9729 - Some early issues.

Post by toddalin »

pete wrote: Wed Mar 17, 2021 6:46 pm

Doing selective hand fitting of parts like this until you find something that works at the factory during assembly still seems like a strange way to run any production line though. Interchangeable parts by properly controlling the manufacturing tolerances was one of the reasons that idea was invented. It's actually a lot cheaper and faster to do it that way.
Maybe, but that is the way it is done. When I snapped a spline shaft, I ordered three and all fit (or didn't) just slightly differently. (Actually only one fit.)
pete
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Re: New G9729 - Some early issues.

Post by pete »

Yep I've seen the results on some of my own equipment about how the cheaper machines get done. Enough so it's a real head scratcher about how or why they'd let there jigs, fixtures, milling and grinding equipment get that far out of alignment. So there scrap rate must be very high. One of my lathes cross slides showed a .003" change over 9" x 4.250" in both directions on what was supposed to be a flat ground surface. I can mill parts to better accuracy than that. The ground surface finish was surprisingly well done, but it was wasted effort imo.

I recently picked up quite a bit of hand scraping information. Again as I mentioned the gib should be checked for straightness. And this morning I ran across a drawing about checking slides with tapered gibs. There recommended procedure for something like a lathes cross slide is to fit the gib and adjust it to it's operating position, then add two dial indicators with there tips on the opposite side the gib is on and at each end of the slides vertical surface. Then try moving the upper part of the slide by hand towards and away from the indicator tips to check the there's no pivoting or excess movement. And if the gibs taper doesn't closely match the taper in the slide then one indicator will obviously show much more movement at the end where the clearances are highest. They also show straightening cast iron gibs using a heavy plate, two spacers towards and under each end of the gib and a C clamp to apply the pressure between the bottom of the plate and at the highest point of the bend on the gib as well as some trial and error until the gib is straight to a dial indicator measurement. Cast iron gibs would be pretty easy to break, so I'd be real cautious trying it.
Diesel Gypsy
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Re: New G9729 - Some early issues.

Post by Diesel Gypsy »

pete wrote: Thu Mar 18, 2021 3:17 pm . . .And this morning I ran across a drawing about checking slides with tapered gibs. There recommended procedure for something like a lathes cross slide is to fit the gib and adjust it to it's operating position, then add two dial indicators with there tips on the opposite side the gib is on and at each end of the slides vertical surface. Then try moving the upper part of the slide by hand towards and away from the indicator tips to check the there's no pivoting or excess movement. And if the gibs taper doesn't closely match the taper in the slide then one indicator will obviously show much more movement at the end where the clearances are highest. . .
This is exactly what my first step was. After Torch convinced me that it was indeed a tapered gib, I adjusted it till the far end had zero movement but the dial indicator showed .018" play at the close end. I think the gib was for a different machine altogether and was mistakenly installed in my lathe. I think that because I can't imagine their equipment being that far out of adjustment! Still, someone should get a kick in the butt for putting it in and not checking it!
pete wrote: Thu Mar 18, 2021 3:17 pm The ground surface finish was surprisingly well done, but it was wasted effort imo.
I agree, it was the same for mine!
Diesel Gypsy
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Re: New G9729 - Some early issues.

Post by Diesel Gypsy »

GOOD NEWS!
I received some new parts from Grizzly today. A new carriage and a new gib.
So the first thing was to measure and the gib was definitely a different taper but the carriage was EXACTLY THE SAME as the original.
I wasn't surprised because I was pretty sure that it was the gib at fault. But since Grizzly was kind enough to send both parts, I now have an extra carriage.
The new gib is actually slightly tighter at the front now but it's not much and I should be able to hone it a little if I need to.
Thanks everyone for the ideas and support and kudos to Grizzly for their quick response. It sounds like they took the parts off a machine they had in stock to make sure that they had a matched set to send to me! :-)
Torch
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Re: New G9729 - Some early issues.

Post by Torch »

Cool. Congratulations.

Now go make some chips ;-)
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