What does a good gib and adjuster look like?
Hi. I have one of those Chinese mini-mills. I know it has its shortcomings
but I just tinker around in my garage so it is OK for me. However, the gibs seem hard to adjust... but since I don't have a real machine to compare it to, I don't know how bad it is. I would potentially like to improve the gibs and adjustment screws if possible. Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? The Chinese mini-mill has gib strips with small dimples in them. The gib adjustment set screws are pilot dog set screws that ride in those dimples. Pretty simple. Unfortunately, for some reason, the gibs tend to tilt and only a thin strip comes in contact with the opposing dovetail instead of staying parallel to the opposing dovetail and having the entire gib strip act as a wear area. I hope that makes sense and I look forward to hearing how the good machines do this. Thanks, Gary |
What does a good gib and adjuster look like?
Gary, are you sure the jibs aren't turned over? The "only a thin strip
comes in contact with the opposing dovetail instead of staying parallel to the opposing dovetail" comment may indicate the jibs are in upside-down. Bob Swinney "Gary H" wrote in message . com... Hi. I have one of those Chinese mini-mills. I know it has its shortcomings but I just tinker around in my garage so it is OK for me. However, the gibs seem hard to adjust... but since I don't have a real machine to compare it to, I don't know how bad it is. I would potentially like to improve the gibs and adjustment screws if possible. Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? The Chinese mini-mill has gib strips with small dimples in them. The gib adjustment set screws are pilot dog set screws that ride in those dimples. Pretty simple. Unfortunately, for some reason, the gibs tend to tilt and and having the entire gib strip act as a wear area. I hope that makes sense and I look forward to hearing how the good machines do this. Thanks, Gary |
What does a good gib and adjuster look like?
In article , Gary H says...
Hi. I have one of those Chinese mini-mills. I know it has its shortcomings but I just tinker around in my garage so it is OK for me. However, the gibs seem hard to adjust... but since I don't have a real machine to compare it to, I don't know how bad it is. I would potentially like to improve the gibs and adjustment screws if possible. Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? The Chinese mini-mill has gib strips with small dimples in them. The gib adjustment set screws are pilot dog set screws that ride in those dimples. Pretty simple. Unfortunately, for some reason, the gibs tend to tilt and only a thin strip comes in contact with the opposing dovetail instead of staying parallel to the opposing dovetail and having the entire gib strip act as a wear area. I hope that makes sense and I look forward to hearing how the good machines do this. A lot of times you'll see that there are pins in the slide that serve two purposes, one is to keep the gib from slipping out the end of the slide, the other is to help keep the gib bearing correctly on the dovetail. If your gib is cocking then you need to look to be sure that it really is the correct trapezoid shape in cross section. It basically needs to 'fill up' the space between the slide and the dovetail way. If it's shaped properly, there is pretty much no way it can shift and bear on a line rather than on a plane. The cup point setscrews typically like to bear on spot faces on the gib, and because the screws are horizontal and the gib face is at an angle, the spot faces need to be at an angle to the gib face. Many times you will see inexpensive slides where they try to 'finess' this by simply using sharp pointed setscrews and have them bear directly on the gib. Those tend to induce cocking. But the general idea is you the pressure from the screws is being applied in a horizontal direction, that has to be so because the threaded holes in the slide are horizontal. But the gib resolves that force into some part that keeps the gib's long surface bearing on the dovetail, and another part that tends to keep the gib socked upwards into the slides female dovetail. The problem happens when the upper edge of the dovetail is at the wrong angle so it does not seat in that upwards direction. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
What does a good gib and adjuster look like?
Gary H wrote: Hi. I have one of those Chinese mini-mills. I know it has its shortcomings but I just tinker around in my garage so it is OK for me. However, the gibs seem hard to adjust... but since I don't have a real machine to compare it to, I don't know how bad it is. I would potentially like to improve the gibs and adjustment screws if possible. Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? The Chinese mini-mill has gib strips with small dimples in them. The gib adjustment set screws are pilot dog set screws that ride in those dimples. Pretty simple. Unfortunately, for some reason, the gibs tend to tilt and only a thin strip comes in contact with the opposing dovetail instead of staying parallel to the opposing dovetail and having the entire gib strip act as a wear area. I hope that makes sense and I look forward to hearing how the good machines do this. Thanks, Gary That sounds like you want to torque the set screws evenly to about 5 to 10 inch pounds. This is the system used on some larger machines rather than having the gib sliding in and letting the taper take up the slack. Normally, the set screws have locking nuts on them. John |
What does a good gib and adjuster look like?
They only go in one way so they aren't turned over. I wish it was that
simple. "Robert Swinney" wrote in message . .. Gary, are you sure the jibs aren't turned over? The "only a thin strip comes in contact with the opposing dovetail instead of staying parallel to the opposing dovetail" comment may indicate the jibs are in upside-down. Bob Swinney "Gary H" wrote in message . com... Hi. I have one of those Chinese mini-mills. I know it has its shortcomings but I just tinker around in my garage so it is OK for me. However, the gibs seem hard to adjust... but since I don't have a real machine to compare it to, I don't know how bad it is. I would potentially like to improve the gibs and adjustment screws if possible. Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? The Chinese mini-mill has gib strips with small dimples in them. The gib adjustment set screws are pilot dog set screws that ride in those dimples. Pretty simple. Unfortunately, for some reason, the gibs tend to tilt and and having the entire gib strip act as a wear area. I hope that makes sense and I look forward to hearing how the good machines do this. Thanks, Gary |
What does a good gib and adjuster look like?
Here is an idea you could try but I should mention that I have not
tried it. Remove the adjusting screws, if they have a pointed end replace them with grub screws that have a cuplike end. Find small steel balls that fit into the screw holes. Tightening the screw onto the steel ball should transfer the horizontal force into an angled force to push the gib flat against the slide. It might or might not do the trick, as I said, its an idea ..... Klaus Gary H wrote: They only go in one way so they aren't turned over. I wish it was that simple. "Robert Swinney" wrote in message . .. Gary, are you sure the jibs aren't turned over? The "only a thin strip comes in contact with the opposing dovetail instead of staying parallel to the opposing dovetail" comment may indicate the jibs are in upside-down. Bob Swinney "Gary H" wrote in message . com... Hi. I have one of those Chinese mini-mills. I know it has its shortcomings but I just tinker around in my garage so it is OK for me. However, the gibs seem hard to adjust... but since I don't have a real machine to compare it to, I don't know how bad it is. I would potentially like to improve the gibs and adjustment screws if possible. Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? The Chinese mini-mill has gib strips with small dimples in them. The gib adjustment set screws are pilot dog set screws that ride in those dimples. Pretty simple. Unfortunately, for some reason, the gibs tend to tilt and and having the entire gib strip act as a wear area. I hope that makes sense and I look forward to hearing how the good machines do this. Thanks, Gary |
What does a good gib and adjuster look like?
Gary H writes:
Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? Connelly's _Machine Tool Reconditioning_ describes the universe of gib designs and their advantages. Consider making a thinner gib with epoxied-on Teflon facing. This will take precision scraping skills that you can also learn from Connelly. You will have buttery soft movement with better rigidity, lubrication, and alignment. Cf. "Bondable PTFE" at mscdirect.com. |
What does a good gib and adjuster look like?
"Gary H" wrote in message
. com... Hi. I have one of those Chinese mini-mills. I know it has its shortcomings but I just tinker around in my garage so it is OK for me. However, the gibs seem hard to adjust... but since I don't have a real machine to compare it to, I don't know how bad it is. I would potentially like to improve the gibs and adjustment screws if possible. Could some one send a picture or describe how the gibs adjusters work on a nice quality machine? The Chinese mini-mill has gib strips with small dimples in them. The gib adjustment set screws are pilot dog set screws that ride in those dimples. Pretty simple. Unfortunately, for some reason, the gibs tend to tilt and and having the entire gib strip act as a wear area. I hope that makes sense and I look forward to hearing how the good machines do this. Thanks, Gary Check out the guides on littlemachineshop.com They have a new mini-mill user guide available for download. Also this is a section on adjusting the gigs for the mini-lathe, but it's the same manufacturer, so it might help: http://www.mini-lathe.com/Mini_lathe...tm#adjust_gibs -- Sending unsolicited commercial e-mail to this account incurs a fee of $500 per message, and acknowledges the legality of this contract. |
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