Author Topic: Better dovetail gibs?  (Read 4401 times)

Offline websterz

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Better dovetail gibs?
« on: April 20, 2009, 05:25:04 PM »
Bolstered by my success at adding tapered gibs to my 7x12 carriage I am now looking at other areas that need help...namely the dovetail gibs on both the lathe and mill. I am not opposed to doing major renovation to my machines in the name of improvement so anyone have any ideas on how to accomplish this?  :proj:

I PROMISE pictures this time!  :bow:
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
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bogstandard

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Re: Better dovetail gibs?
« Reply #1 on: April 20, 2009, 05:52:23 PM »
Hi W,
It looks like you are happy with the job you did, and want more of the same precision 'fix', better than adrenalin any day.

I don't think there is much else you can do with the other gibs on the lathe, other than making sure they are perfectly flat. If you know someone with a surface grinder, that is only a ten minute job, but make sure they DON'T use the mag chuck, all it will do is flatten them out when turned on and machined, and when turned off they will still be bent.
When I did Darrens lathe, all I did was adjust them correctly, and they were smooth as silk with no wobble. It is just a matter of taking your time and striking a good balance. I also adjusted the leadscrew nut to reduce the excessive backlash that was on the machine.

Depending what mill you have, depends on what can be done. Tapered gibs on mills have been in use for a long time now, at least 25 years on the mill/drills, so yours might already have them. Again, correct adjustment of gibs and nuts makes all the difference.

Plus of course, as I always say, the correct lubricant, at very regular intervals.


Bogs


Offline websterz

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Re: Better dovetail gibs?
« Reply #2 on: April 20, 2009, 06:17:30 PM »
Hi W,
It looks like you are happy with the job you did, and want more of the same precision 'fix', better than adrenalin any day.

I don't think there is much else you can do with the other gibs on the lathe, other than making sure they are perfectly flat. If you know someone with a surface grinder, that is only a ten minute job, but make sure they DON'T use the mag chuck, all it will do is flatten them out when turned on and machined, and when turned off they will still be bent.
When I did Darrens lathe, all I did was adjust them correctly, and they were smooth as silk with no wobble. It is just a matter of taking your time and striking a good balance. I also adjusted the leadscrew nut to reduce the excessive backlash that was on the machine.

Depending what mill you have, depends on what can be done. Tapered gibs on mills have been in use for a long time now, at least 25 years on the mill/drills, so yours might already have them. Again, correct adjustment of gibs and nuts makes all the difference.

Plus of course, as I always say, the correct lubricant, at very regular intervals.


Bogs



As luck would have it I myself OWN a surface grinder.  :D Although I have found an alternative solution I think. I have located a drawing of a fixture for milling new dovetail gibs. I am going to give all the dovetail faces on the lathe (and later the mill) a good lapping and mill up new gibs from ali-bronze. I recently bought a box of the correct size dog-point set screws for the dovetail adjustments and will cut a groove along the length and add in a piece of nylon monofilament so they are self-locking. That should help hold the adjustment when I do finally get it tweaked just right. As promised I will take lots of pics along the way. 

:proj: here I come!!
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
 :med:

Offline Darren

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Re: Better dovetail gibs?
« Reply #3 on: April 20, 2009, 07:34:25 PM »

When I did Darrens lathe, all I did was adjust them correctly, and they were smooth as silk with no wobble. It is just a matter of taking your time and striking a good balance. I also adjusted the leadscrew nut to reduce the excessive backlash that was on the machine.




And it shows, I really like using this machine now.

I have lost one outside jaw when I moved so it's a bit limited to what size I can fit in the chuck. I must try to find out if replacements are available.

Before it was Bogified I couldn't be bothered, but now it's high on the to do list  :ddb:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)