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VMC Mill saddle parallelism??

Fabric8r

Plastic
Joined
Feb 9, 2006
Location
Milwaukee, WI
Hello. I Have a question about the geometry or parallelism in my mill saddle. I Know that the Parallelism between the 2 ways in the long direction Needs to be the same. So there is no twist when traveling back and forth. But I am wondering what about in the short direction. When I indicate between the 2 of them, I am about .0015 out of Parallel. I know when i put the table on and match scrape the Turkite. I can get them to match. but will that be Fine? or is there something im missing. Im thinking it will be Fine? Also between the 2 ways one is lower Than the other by like .004 thou. I can make that up too with the thickness of the tukite. Is that ok?
I would try to correct this, but the Ways im working on are Hardened and im doing this without a surface grinder.

Thanks in advance for any Help, Scott!!
 
Ok, I will try to post pictures. The machine is a Daewoo Ace V50. I'm gonna try to attach 3 pictures. First the machine, then the saddle, then a drawing of what I'm talking about.

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Thanks, that's what I was thinking too. The only thing I can see after thinking about it for a while. Is. With weight on that side with the taper it will probably pull the table back and put more wear on the back Gibb.
I think I'll see if i can correct it a little better. Its one of those things that will bug me, in the back of my mind.
But still would be nice to know if that would be of any concern or not. For me and others.
Thanks!
 
How do you expect to get a precision spec while the saddle is sitting on wood? From my experience if the table underside Turcite is worn away the bottom of the saddle is worse. Even if your measuring the table on the worn saddle ways your getting bad measurements. Your calling what looks like hold downs , Gibs? I am about 4 hours away and can come and help you figure out your problem. But at my hourly rate plus expenses. PM me for more info.

Also I bet we could take it over to Cash Masters and set the saddle and table on his HUGE granite table and check it on some precision blocks or 3 points. Mattison Grinding / Way Grinding - Knifemaker.com
 
I have read many of your previous posts. And I thought about it. So I built a 3 point table for it to sit on. Thanks for your offer of coming to help. But I think I'm getting closer now. I am going to try to correct the .0015 parallelism. It was a ton more work. But I new in the back of my mind it would bug me. Again thanks for all the info you guys share here!

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Why didn't you show us that before? To get a reaction? Why was it sitting on the wood? Have you checked the gibs on the saddle bottom? How did you check the way front way being tapered ? If it is tapered because of wear, that must be in the center and not on the ends? Did you mike the underside on the ways and top all the way around the saddle top. Every 6". How about using the PM photo download system so we don't have to buy photobucket.
 
I think probably because he had one simple geometry question that he wanted to get an answer to. To do all the rest of that would require quite a lot of pictures and writing/typing.

I too would be interested to know how this was quantified. The .0015" tilt in what, 2½" width is no big deal to me so long as it's planar all the way down and the Turcite is scraped to compensate. As Richard alluded, it's difficult to check that way geometry without a good reference like a very large surface plate though. Fabric8r, did you use one? Or just a straight edge? It does appear from the picture as though he's done some scraping on that .0015" tilted way surface.
 
EKretz, you are exactly right. I just asked for the one geometry question. And it got twisted into this. But that's ok I guess. The more questions asked the more for myself and others to learn from. Except the fact that there is So much BS to sift through.
I am NOT a professional scraper, as I'm sure many on here are as well. I Am Always learning. And yes I did make a few mistakes already in my process. I started out with the saddle sitting on 3 points on my 5' x 2.5' surface plate. It did not leave me much room to work around the outside with my indicator stand. But what I found was the saddle was bowed. It was about a .001-.002 high on the ends "long ways" and low in the center. I did check for twist from side to side. My 1st mistake was. I did not check for twist or parallelism in each individual way the short 3" distance. My 2nd mistake was setting it on wood blocks. I did scrape the side that has the .0015 taper in it, while sitting on the wood blocks. It wasnt until I was using that side to indicate parallelism to the other side, that i noticed a problem. So that's when i decided i better make a 3 point stand for it so i could use my precision level as well. And to take out any unseen stresses.
Yes i also miked the underside of ways every 4" all the way around. So using 3 different methods after getting it on 3 point.
1st. Check was My indicator stand Set on 1st scraped side and indicated across to other side. As I slid it tword and from the other way " not long ways "I saw a differance in the reading.

So 2nd. I set my 4ft parallel across the 2 ways and a flash light on the back side and I could see the one way. The first one I scrapped. Was angled. I also confirmed this by sliding a piece of shim stock under the parallel.

3rd. My level set long ways and also 90deg short ways on each way and moved every 4". I was able to see the way was not parallel to the other way" short distance as in picture drawn above" And also each individual way was twisted as well.

I have got the second way scrapped and parallel in both planes. Now I am going back to the first way to correct my mistake. Because it is not only out of parallel. But it is also slightly twisted.
I hope this clears some things up. Again, THANK YOU guys for your help and knowledge!!
 
Fab, just remember that your post is in the Machine Reconditioning section. In here, many of the guys are the fussiest of the fussy, because that's what it takes to work to the level required for machine reconditioning. It's nothing personal against you.

That said, it sounds like you have a handle on it just fine. Good luck with your rework.
 
Many of us like to get the facts straight before answering. I will not guess an answer. That may seem fuzzy to some. I say better safe then sorry. If one gets upset because I ask questions, sorry. I want to give you the best advice possible. If you want to call me ...PM me for my phone number.
 








 
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