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Tapered Gibs
- Thread starter tekfab
- Start date
I'm sure Richard will have more to add, but here is what I know.
Tapered gibs bear against both surfaces over their full length because of the way they adjust. this means even pressure over the length of the slide. They are also easier to adjust because you typically have a single adjusting screw (and a stop screw). With parallel gibs they are typically adjusted (is there any other way to adjust this type, I have never seen one...) by using set screws to apply pressure to the gib strip. This creates pressure points where the screws contact. You tend to get uneven wear, and the gib strip doesn't bear evenly.
Parallel gibs do work, I had them on my first lathe, and first mill. Both my current machines have tapered gibs, and I think it's definitely an improvement in design.
Tapered gibs bear against both surfaces over their full length because of the way they adjust. this means even pressure over the length of the slide. They are also easier to adjust because you typically have a single adjusting screw (and a stop screw). With parallel gibs they are typically adjusted (is there any other way to adjust this type, I have never seen one...) by using set screws to apply pressure to the gib strip. This creates pressure points where the screws contact. You tend to get uneven wear, and the gib strip doesn't bear evenly.
Parallel gibs do work, I had them on my first lathe, and first mill. Both my current machines have tapered gibs, and I think it's definitely an improvement in design.
What i can't get my head around is how putting something tapered into something parallel works, of course i'm assuming the dovetails are machined parallel ? haven't checked that yet !
I'm hoping someone can give me an idiot slap. It's not the end of the world but before i try to measure/adjust it i'd like to know how/what i'm trying to achieve. :whiteflag:
Mike Young
I'm hoping someone can give me an idiot slap. It's not the end of the world but before i try to measure/adjust it i'd like to know how/what i'm trying to achieve. :whiteflag:
Mike Young
Here is a video on scraping in a tapered gib.
[video=youtube_share;LUEQhgGazAo]http://youtu.be/LUEQhgGazAo[/video]
If you pause the video at about 2:26, you can see he has the two parts of the slide layed out nicely so that you can see the sliding part is parallel, and the fixed part (the one containing the gib) is clearly tapered on one side.
[video=youtube_share;LUEQhgGazAo]http://youtu.be/LUEQhgGazAo[/video]
If you pause the video at about 2:26, you can see he has the two parts of the slide layed out nicely so that you can see the sliding part is parallel, and the fixed part (the one containing the gib) is clearly tapered on one side.
- Joined
- Jul 1, 2012
- Messages
- 1,356
I wanted to let the other guys speak on this one and DMS has done a fine job. Tapered gibs are the best way to go as described by the guys. The majority of machine builders put the Tap gib on the shorter side of the way system and they are stationary as you see on Bridgeport mills, they ride against the longer ways that are scraped parallel to one another, The back of the gib is tapered and it goes against a tapered side of the short part. A small minority of machine builders put the tapered gibs on the long side of the way system. Others may have 2 tapered gibs that are opposing each other on the short side of the ways. This can get complicated trying to explain with-out pictures, but the bottom line is tapered gibs are the best way to go.
I find the cheaper or not as accurate machines use the the flat gibs with set screws.
Rich
PS: Thanks Seana for those great pic's and discription
I find the cheaper or not as accurate machines use the the flat gibs with set screws.
Rich
PS: Thanks Seana for those great pic's and discription
Last edited by a moderator:
Thank you all for your help and information. What i can't decide is how easy it will be to measure up and scrape compared to a parallel set up ? Both the top slide and cross slide have the tapered gib set up although it's the cross slide that i would like to "fix" first but as its a 1932 machine i'm sure another bit of time won't harm it ! I have limited experience of doing a cross slide but it was a parallel gib type and didn't need much attention.
Mike Young
Mike Young
- Joined
- Jul 1, 2012
- Messages
- 1,356
Take some pictures and add them here please. Or if you search YouTube you will see how that same guy does the other 1/2.
Myabe DMS has it, I watched in once, so its there. Rich
Here is the part of the video with the actual scraping. The previous one I linked just did a dry run through fitup.
[video=youtube_share;esAqz6bCVyQ]http://youtu.be/esAqz6bCVyQ[/video]
If the machine is already a tapered gib machine, you will want to stick with that. Keep in mind, I'm just a neophyte, I have only done parallel gibs as well, and most of my experience is "self taught". That being said, Nicks videos don't make it look any harder than a parallel gib.
[video=youtube_share;esAqz6bCVyQ]http://youtu.be/esAqz6bCVyQ[/video]
If the machine is already a tapered gib machine, you will want to stick with that. Keep in mind, I'm just a neophyte, I have only done parallel gibs as well, and most of my experience is "self taught". That being said, Nicks videos don't make it look any harder than a parallel gib.