Mill vertical slop
I have a new Sieg X3/Grizzly and am trying to teach myself to use it. Got a couple questions:
1. It has a set table, vertical movement is via dovetailed vertical column and headstock over the table which slides up and down. Plus quill motion, of course. Problem is that when I set vertical height by kissing off the cutter on a piece of stock, then lock in the height by tightening the lock on the gibs on the vertical column, I lose a couple thousands as the headstock is sagging downward in the gibs under gravity and as you tighten the gibs, it sits up straighter. In a Bridgeport or knee mill, the weight of the knee is working to hold the tolerance against the screw and gibs so you don’t see this effect as much. But on a cheap chinese mill, it is very observable. Any of you figure out how to work around this or modify the machine? Or do I just use machinist’s kentucky windage and factor in the sag on each vertical kiss off? I don’t know anything about DROs yet. But since the DRO info is coming off the slide, I would suspect it would not register any change in height as you tightened the gibs.
2. Is there a separate DRO for the quill or is the quill always left out of any DRO? I need to drill very accurately guaged depths in a project I’m going to start in a couple weeks and my X3 does not have a quill stop to control depth, I think I’m going to have to make one before starting my project.
thanks,
walt
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Viewing 14 replies - 1 through 14 (of 14 total)
The X3 is a nice size machine for the home shop but the X2 is all ive got space for ( piece of crap 👿 ) . As with all these imported mills they need work to make them any good. Ive just spent 12 hours hogging Seans Bridgeport in the sweltering heat , while abusing his excellent hospitality to machine my dovetails to hopefully stop binding.
One thing that can help the flex for the X2 and its posted on most machining forums is to fill the Z axis column void with epox resin , it will act as a dampner for vibration and sort the flex ( im about to do it myself ). Bracing the column on the X3 seams to be the way to go as i believe its just a U shaped casting , see the link below for info.
http://www.cnczone.com/forums/showthread.php?t=54679&highlight=column+flex
L8r 😀
Dont let that X3 hold you back. Buba has an X2 and makes stuff like this. We all would love to have a Bridgeport but dont let that stop you.
That X3 is a better machine then what most of us are using and yet we manage to turn out some nice work.
Update: with the gib semi locked, dragging just a bit, the difference from semi locked (still can move it up and down) to locked is about .0015″ …not too bad, I can fudge that when setting up for drilling. Now I just have to build a quill stop for this machine.
I have an appointment this weekend to go look at a machine a local shop is getting rid of. It’s an old Kierney-Trecker horizontal mill that someone converted and adapted a Bridgeport Series I head to. If it’s a J head, I might just buy it and sell this X3, although it’s a nice little machine. If you take it slow, nothing wrong with the X3. But can’t hold a candle to a Bridgeport. The guy says the total weight is near 5000 lbs. Gotta rent another forklift 🙁
walt
Has anyone got any experience with the Shumatech DRO350? Seems like a neat way to go, but since it uses cheap looking scales, I don’t know if they’d be dependable…
My shop is still broken down from the move, but I’ll get a link for you from the 6×26 milling machine site for you. Lots of great info there, along with set-ups for smaller mills.Yep, Here it is!
Mike, can you send me a pic of that quill indicator setup?
thanks,
walt
I know what you mean Walt. I would love to have a Bridgeport. My shop is so small that a BP would drag it down the black hole! 😯 🙁
Computer paper. Great Idea! Thanks!
I really do like the digital caliper attached to the quill indicator. It will allow me to know exactly the depth at about 14.00 from harbor freight. Their smallest model is by far the most accurate.
😀
Mike
Thanks for the advice, guys. Mike, I know a lot of others who use the same trick with the paper, but they use computer paper, which is very uniform in thickness. You only need about a 1″ square piece, just until the cutter grabs it and moves it. One guy puts a dot of oil on the paper and sticks it to the work, then lowers the quill or raises the knee.
I will give it another go this weekend with the head coming down partially locked like you and Walter suggested. My cheapie machine doesn’t have a knee, the ways are locked on the bottom and the headstock moves up and down, which is why I’m having problems. We’ll just have to wait and see if it gets better or worse as the gibs wear in.
My quill is like you said, terribly marked. It does not have a quill stop, so I think I”m going to have to rig it with one as I need the height indicator like you mentioned. I rigged a feeler to the side of the machine so I can read the head height directly, but it doesn’t tell me the quill motion. What a pain.
On the plus side, this X3 can cut better than I thought it would. I figured I’d have to limit myself to very small cuts in steel and take off only a few ten thousands at a pass, but so far it has been pretty good with heavier cuts and no chattering. But I’m still kicking myself for passing on that Bridgeport when I had the chance.
walt
VERY WELL :11
Hey Walt!
Well we all do it a little different. I have the Grizzly small Knee mill. Since the knee is not as heavy as a B’port, I have to be careful.
Here is the two tricks I use. First, I get the knee to just about where I want it and semi lock it. Just tight enough for it to move with its own weight when raising it without shifting from the gib. . I then use cigarette paper which is .001 for a height Gage. I then know just how much to move it.
Another method is to use the quill feed. But it is poorly marked. I went to harbor freight and bought a cheap digital caliper and rigged it to the Quill stop and frame. It will give the exact amount of feed. Others use a height gage rigged to the Quill and the work.
On a funny note, a good friend of mine just retired from the Killeen PD. He was the night shift super. He is learning to make Custom Folding Knives. (And doing a fine job)! Before he left my shop, I said here, I’ve been saving these for you.
Well he took one look at the rolling papers from ZIG-ZAG and ask What The Hell do you think I want those for. I can’t have those in my car! 😯
I showed him what I used them for and explained that I had learned the trick from the Loveless Shop. But with cigarettes being so expensive, that I had to come up with an alternative! He laughed and stated that that was the best excuse for having papers in possession that he had ever heard. He is now using them and agrees that they work very well! 😀
Mike
Walt-
I am just a wood man but, couldn’t you have a gauge, pre determined thickness, say .100 brass, whatever, to make up the difference of the head being loose, and the head being tight ?
Or is there much more to it ?
If ya give the head the same amount of loosen to adjust, wouldn’t it be constant upon re-tighten?
Or am I just full of shit?
SAW
On my X2 never finish with a large cut maybe .012-25 to get to final dimensions.
What I have done in the past is make practice cuts and measure with a height gauge. When I get to .000″ I measure the piece and see what the final dimension is and then adjust the head. And go from there.
Due to vibration you need to know check it out
Walt, lock her up close and indicate the quill to depth.
makes me appreciate my knee mill 🙂
Walter….
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Thanks for the link Buba!
Mike