MadModder

Gallery, Projects and General => Gallery => Topic started by: wheeltapper on May 10, 2011, 02:41:12 PM

Title: small mod on a Chester Comet lathe.
Post by: wheeltapper on May 10, 2011, 02:41:12 PM
Hi
For some time now I've been getting fed up with the topslide on my lathe.
it gets in the way, it puts too much flex in the tool ( tool cutting on the return pass) and I only need it for cutting a taper.

so I took it off.

heres what I have now.

(http://i293.photobucket.com/albums/mm72/wheeltapper_2008/model%20engineering%20stuff/topslidefreetoolpost.jpg)

I also made a seperate block to go in place of the QC holder to hold standard half inch round shank boring bars.

(http://i293.photobucket.com/albums/mm72/wheeltapper_2008/model%20engineering%20stuff/topslidefreeboringbarholder.jpg)

the whole thing is much stiffer now.

Roy.
Title: Re: small mod on a Chester Comet lathe.
Post by: spuddevans on May 10, 2011, 03:26:29 PM
That looks really effective Roy :thumbup: :thumbup: That is a mod that I could do with on my lathe, it might remove some of the elastic properties that my little lathe suffers from.


Tim
Title: Re: small mod on a Chester Comet lathe.
Post by: j45on on May 10, 2011, 05:45:52 PM
Nice one Roy  :bow:
I have a C4 as well and the top slide is a bit poo I have the gibs locked up almost solid.
I like your solid mounting Idea I may have to copy it  :thumbup:

PS what is that in you tail stock  :scratch:
Title: Re: small mod on a Chester Comet lathe.
Post by: raynerd on May 10, 2011, 06:18:23 PM
Wheeltapper - the chap who I visit quite often has an Asian made lathe and he has done exactly the same! It seems the topslides are made of rubber. Nice job, thanks for showing.
Title: Re: small mod on a Chester Comet lathe.
Post by: Stilldrillin on May 11, 2011, 02:08:31 AM
Yep!

Me too.....  http://madmodder.net/index.php?topic=2464.0

It doesn't half make a difference!  :thumbup:

Like your rear toolpost too!  :clap:

David D
Title: Re: small mod on a Chester Comet lathe.
Post by: picclock on May 11, 2011, 02:31:58 AM
Hi Roy

That's a very nice looking job. I did this to my Real Bull 7x14 some time ago and the improvement was spectacular. But I made mine out of a block which could be fitted 4 ways allowing different toolholder offsets and overhangs for awkward jobs. Mine attaches with 4 cap head bolts.

(http://i917.photobucket.com/albums/ad19/picclock/P1000343.jpg)

IMHO, its probably one of the most worthwhile mods for smaller lathes, as it allows easy parting and much better finishes just because of the improvement in rigidity. For fine feed a handle on the right hand end of the leadscrew does the trick on mine.

Now if only I could figure out how to turn tapers without having to reset that precision tailstock alignment .. . :scratch:

Best Regards

picclock



Title: Re: small mod on a Chester Comet lathe.
Post by: jim on May 11, 2011, 02:53:18 AM
worth while mod :clap:

Title: Re: small mod on a Chester Comet lathe.
Post by: wheeltapper on May 11, 2011, 05:50:55 AM
Nice one Roy  :bow:
I have a C4 as well and the top slide is a bit poo I have the gibs locked up almost solid.
I like your solid mounting Idea I may have to copy it  :thumbup:

PS what is that in you tail stock  :scratch:


Hi
Its a cork, It keeps the crap out. :lol:

Roy
Title: Re: small mod on a Chester Comet lathe.
Post by: jim on May 11, 2011, 10:05:37 AM
Nice one Roy  :bow:
I have a C4 as well and the top slide is a bit poo I have the gibs locked up almost solid.
I like your solid mounting Idea I may have to copy it  :thumbup:

PS what is that in you tail stock  :scratch:


Hi
Its a cork, It keeps the crap out. :lol:

Roy

likewise! its easier to push a cork in, than clear all the crap out!
Title: Re: small mod on a Chester Comet lathe.
Post by: wheeltapper on May 11, 2011, 10:41:35 AM
Hi
Just as a tailpiece to this I tried a little test.
I set up a dti on the cross slide with the probe resting 2mm from the tip of a r h tool.

taking a 2 mm cut with the toolpost mod I got a tool deflection of .0004"

with the topslide refitted I got over 7 times that deflection.

I think it was worth doing.


there is, however, a downside (isn't there always) I now have no fine feed along the lathe, I have not got a handwheel on the leadscrew and even if I had one it would be a pain because there is no quick way to disconnect the leadscrew apart from removing a change wheel.


Ho hum, you win some, you lose some.

Roy