Author Topic: A couple of small roundtoits today.  (Read 8963 times)

Offline websterz

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A couple of small roundtoits today.
« on: April 09, 2009, 08:14:44 PM »
While I am waiting for the electrician to return I figured I would get a few whatnots knocked off the list.

First I am starting to fine-tune my mill.  :proj: My extended Z axis rack will be here tomorrow. In the meantime I eliminated a BIG hunk of Z axis backlash:



I never understood why they put a u-joint on the fine feed mechanism...to get past the p**s-poor alignment of the rest of the system perhaps? Here's the solution:



When I change out the rack and replace the torsion spring with a counterweight I will shim the rack to get better engagement. By changing out the u-joint with a solid rod and peening the castleated clutch (I forgot to mention that) I got my backlash down from almost .070 to a much more acceptable .025.

And finally a rack for my R8 tooling, collets on the spinner endmill holders in the back:


Not huge projects but they were fun.
« Last Edit: April 09, 2009, 09:29:27 PM by websterz »
"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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Offline sbwhart

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Re: A couple of small roundtoits today.
« Reply #1 on: April 10, 2009, 02:03:30 AM »
Hi Websterz

Interesting couple of modifications you've done there  :clap:

Have Fun

Stew
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Offline Stilldrillin

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Re: A couple of small roundtoits today.
« Reply #2 on: April 10, 2009, 02:13:10 AM »
2 nice mods there Websterz!  :clap:

I too wondered about the coupling.......  :scratch:

Fortunately, mine is still unworn. Backlash is at around .020".

Must remember your mod, for later.....  :thumbup:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Bernd

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Re: A couple of small roundtoits today.
« Reply #3 on: April 10, 2009, 09:08:53 AM »
Websterz,

I have the Grizzly version of that mill. I could never understand why they had the u-joint either. Kind of makes sense now that you mention it.

Nice little projects by the way.

Do you know if your lead screws are 16TPI or 20TPI? There's a mod to change them to 20 TPI from Micro Mark. Check out my website on the write up I did of the my mini-mill.

Regards,
Bernd
You can't fix "STUPID".

Offline Brass_Machine

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Re: A couple of small roundtoits today.
« Reply #4 on: April 10, 2009, 11:49:48 AM »
Nice. Those are 2 I have to do.

Eric
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Offline Darren

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Re: A couple of small roundtoits today.
« Reply #5 on: April 10, 2009, 11:51:35 AM »
Wonder why they didn't do that in the first place, nice mod  :thumbup:
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Offline Brass_Machine

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Re: A couple of small roundtoits today.
« Reply #6 on: April 10, 2009, 04:24:47 PM »
... and peening the castleated clutch (I forgot to mention that) I got my backlash down from almost .070 to a much more acceptable .025.

...

Could you explain how you peened the clutch?

Thanks
Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline websterz

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Re: A couple of small roundtoits today.
« Reply #7 on: April 10, 2009, 07:53:41 PM »
... and peening the castleated clutch (I forgot to mention that) I got my backlash down from almost .070 to a much more acceptable .025.

...

Could you explain how you peened the clutch?

Thanks
Eric

Simple really. Pull the handle assembly off the mill and turn it, castle-side up, on a hard surface like the anvil on a bench vise. Take a small ball-pein hammer and a center punch and put a small punch mark in the center of each little square face on the handle portion of the clutch. This swells the face just enough to tighten the fit, a little goes a LONG way. If you get it too tight just tap it gently in place on the mill with a mallet and remove the same way. Rotate to different positions tapping the handle on and off to make sure it is not too tight and you are done. There is a set screw in the center hub of the handle (on mine anyway...YMMV) that presses a spring loaded ball against the shaft, make sure not to lose the ball or spring when you remove the handle assembly.
"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 websterz

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Re: A couple of small roundtoits today.
« Reply #8 on: April 10, 2009, 08:13:20 PM »
Websterz,

I have the Grizzly version of that mill. I could never understand why they had the u-joint either. Kind of makes sense now that you mention it.

Nice little projects by the way.

Do you know if your lead screws are 16TPI or 20TPI? There's a mod to change them to 20 TPI from Micro Mark. Check out my website on the write up I did of the my mini-mill.

Regards,
Bernd

Mine are 16 tpi. I was going to convert to 20 tpi but I plan to add homebrew DRO's so the .0625 thing is not going to be an issue much longer. Aside from a finer feed I personally don't feel the need to change the leadscrews.

In addition to the longer Z rack I also have replacement nuts for the X and Y axis coming. I am going to do the anti-backlash mod to my old ones and keep the new for spares. For those that don't know that mod you take the brass nut and slit 90% of the way thru, starting from the square edge. This leaves a small portion on the radiused end that holds, what is now basically two thinner brass nuts together. Drill a hole thru one side and tap for a setscrew. The pic calls for 10-24 but I prefer 10-32, especially in brass . You tighten the screw to spread the nut apart, tuning out backlash.  It also stops the annoying harmonic whine that seems to plague the X axis.



My electrician was a no-show so I started on another long-overdue project...X axis power feed. I managed to recycle part of the Z axis fine feed mechanism, using the worm-gear end of the old U-join as a coupling to join my cordless drill motor to a spring loaded clutch for disengaging the power feed. The little bit of Chinese steel was already the right OD for the bronze bushing I had in the mounting plate so the part was good for something after all! I tossed the rest in the odd bits box for a rainy day. I will post up pics of the power feed project tomorrow.  :dremel:
"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 Stilldrillin

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Re: A couple of small roundtoits today.
« Reply #9 on: April 11, 2009, 03:32:43 AM »
Nice nut mod!  :clap:

Thanks.....  :thumbup:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Bernd

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Re: A couple of small roundtoits today.
« Reply #10 on: April 11, 2009, 11:01:59 AM »
I like that mod you did to the nut. Never thought of that when I had mine apart. Looks like the next project after rebuilding/modding the Grizzly lathe will be the mini-mill.

Bernd
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Offline websterz

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Re: A couple of small roundtoits today.
« Reply #11 on: April 11, 2009, 03:00:28 PM »
I like that mod you did to the nut. Never thought of that when I had mine apart. Looks like the next project after rebuilding/modding the Grizzly lathe will be the mini-mill.

Bernd

Not my idea...I got it on a Grizz mini mill Yahoo group.
"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 shoey51

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Re: A couple of small roundtoits today.
« Reply #12 on: April 11, 2009, 05:15:44 PM »
nice mods there I muct keep them in mind  :thumbup:

Offline Stilldrillin

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Re: A couple of small roundtoits today.
« Reply #13 on: April 12, 2009, 02:25:17 AM »
nice mods there I muct keep them in mind  :thumbup:

So very many ideas on here.......  :clap:


So little memory capacity.......  ::)

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Bernd

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Re: A couple of small roundtoits today.
« Reply #14 on: April 12, 2009, 08:34:42 AM »

So little memory capacity.......  ::)

David D

 :lol:     :lol:
You or the computer?

Bernd
You can't fix "STUPID".

Offline Stilldrillin

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Re: A couple of small roundtoits today.
« Reply #15 on: April 12, 2009, 08:51:59 AM »

So little memory capacity.......  ::)

David D

 :lol:     :lol:
You or the computer?

Bernd

Oi Mate!!!

I`ll av you know there`s nowt wrong wi my computer........  :thumbup:

 :lol:   :lol:   :lol:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!