Adjustable v-ledges

[dcostaParticipant @dcosta]

Hi Everyone,

 

I have an Optimum BF20 milling machine.

Optimum says it has adjustable v-ledges in both X and Y axis.

 

I would like to know more about the way the v-ledges work.

So I would like to know where I can find some information on the

way they do their function.

 

Any help with URL addresses or other information will be greatly appreciated.

Cheers

Dias Costa

[dcostaParticipant @dcosta]

[JasonBModerator @jasonb]

If you look up “Gib Strips” or “Gib strip adjustment” that should answer your queries, its just a poor translation.

 

Jason

[dcostaParticipant @dcosta]

Hello Jason.

Thank You for Your help.

 

May be I’m wrong but I thought that the “Gib Strips” words were used to describe astraight kind of Gib Strip which You adjust by means of several screws along it.

 

The kind of “Gib Strips” in my milling machine is adjustable by means of two screws

positioned in the top of one side of the dovetail in each of the X , Y and Z axis. So, in

each axis, one screw tights the Gib Strip” against the other. Or so it seams to me.

 

I must add that in a phone call to the distributor in Portugal I was said the “Gib Strips”

in my machine are wedge shaped (or tapered).

To make clear my first message let me cite what the distributor says in the leaflet

about my milling:

“Robust and precise dovetail control adjustable without clearance with V-ledges“.

 

If the Gib Strips are tapered shaped, then there must be a pair of them in each

dovetail in such a position that when we tight them against each other, there always a

straight line formed in contact against the dovetail. But in my milling there’s only one

Gib Strip! How does it work?

Cheers

Dias Costa

 

 

[John HaineParticipant @johnhaine32865]

Fixed part of the slide has the dovetail where the gib strip goes not parallel to the other side of the dovetail, by an angle that equals the taper of the gib strip.  Then by adjusting the logitudinal position of the strip you take up clearance.

[dcostaParticipant @dcosta]

Hello John.

Thank You for Your help.

 

Do You know, by any chance, if the not parallel side in the dovetail is in the male side or in the female side?

 

 

Cheers

Dias Costa

[KWILParticipant @kwil]

The knee or saddle side will be parallel one, the outer of the strip and the inner of its mating half will be the taper.

[GoCreateParticipant @gocreate]

Hi

These jib strips sometimes have a screw at opposite ends as on my own machine. To reduce clearance you have to back off the screw at the thin end then make your adjuustment using the screw at the thick end. Once adjusted retighten the screw at the thin end. (and vice versa). Don’t know if this applies to your machine, if you only have a screw at one end (it wil be the thick end) then screwing it in will reduce clearance and vice versa.

Hope this helps

Nigel

Edited By tractionengine42 on 14/07/2010 23:43:58

[Billy MillsParticipant @billymills]

Another way of thinking about the tapered gib is to consider two long thin wedges pointing in opposite directons and held together so that  when the two wedge angles are the same, the outside long faces are parallel. If the wedges are pulled apart the parallel faces are closer, when the wedges are pushed together the parallel faces move apart.

 

One wedge is then the tapered gib, the other wedge is cut into the female dovetail on one side only. So by pushing the wedge into the dovetail the male part can be clamped between parallel sides so that  sideways movement is prevented but the male can slide along the dovetail.

 

The tapered gib is far more rigid than the conventional gib strip because it is supported along the whole inside face of the dovetail, it is also a great deal simpler to adjust. But it is far more demanding to make  because it has to be accuratly made as opposed to the normal gib strip which relies on many screws being adjusted to take out build errors.

 

Tapered gibs are found on some quality lathes and mills, often with a single screw adjustment ( and locking device). Seem to recall a recent project in MEW that used a tapered gib.

Regards,

Alan

[dcostaParticipant @dcosta]

Hello Kwil, Nigel and John.

 

Thank You for Your prompt help.

Now I understand how the tapered gib strips work.

 

 

Cheers

Dias Costa

[Author]

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