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Gallery, Projects and General => Project Logs => Topic started by: Twinsquirrel on March 29, 2009, 05:01:49 PM

Title: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: Twinsquirrel on March 29, 2009, 05:01:49 PM: Well this is something Ive been meaning to do for a while, the cross slide travel is not what it could be on the mini lathe and I often feel I could do with an extra inch or so (no sniggering). The idea came from this site http://warhammer.mcc.virginia.edu/ty/7x10/xslidemod.html (http://warhammer.mcc.virginia.edu/ty/7x10/xslidemod.html)

(http://i294.photobucket.com/albums/mm108/twinsquirrel/25032009064.jpg)

As the first job for my new mill I decided to live dangerously and mill out the excess material on the saddle :dremel:, believe it or not this is how it looked from the factory :scratch:

(http://i294.photobucket.com/albums/mm108/twinsquirrel/25032009065.jpg)

And after a bit of judicious metal murdering just enough material was removed to allow the full length of the screw to be used..

(http://i294.photobucket.com/albums/mm108/twinsquirrel/29032009079.jpg)

Heres a few boring pics of turning the spacer..

Finishing cut, 34mm

(http://i294.photobucket.com/albums/mm108/twinsquirrel/25032009068.jpg)

Parting off, total length of spacer 25mm, I know I shouldn't really use the live center to support the workpeice when parting but I find it easier that way. BTW the new taper bearings in the lathe have greatly increased my confidence when parting...look I even managed to take a pic while parting!!

(http://i294.photobucket.com/albums/mm108/twinsquirrel/25032009070.jpg)

I got a bit over-excited and forgot to take any pictures of the milling but here is the finished part..

(http://i294.photobucket.com/albums/mm108/twinsquirrel/29032009072.jpg)

And here it is mocked up on the lathe..

(http://i294.photobucket.com/albums/mm108/twinsquirrel/29032009076.jpg)

The only thing left to do is extend the shaft on the cross-slide screw then I should be good to go..

David
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: Darren on March 29, 2009, 06:30:59 PM: Quote from: Twinsquirrel on March 29, 2009, 05:01:49 PM

believe it or not this is how it looked from the factory :scratch:

(http://i294.photobucket.com/albums/mm108/twinsquirrel/25032009065.jpg)

I hope they've got those rats trained better these days :ddb:

That's some very nice work so far David. What do you mean by "extend the shaft on the cross-slide screw"

I suppose you will show us soon enough? :thumbup:
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: cedge on March 29, 2009, 10:24:01 PM: TS...
That was one of the best mods I ever made to my little 7x14. Adding onto the lead screw and stepping up to a 5 inch chuck made it all work together. The lead screw mod was no big deal. I ordered a spare from Little Machine Shop, cut off what I needed and then drilled and reamed the end of the original to accept a turned down end on the new one (light interference fit). I secured the joint with red loctite and used the bronze lead screw nut to align the thread ends. I bit of hand dressing with a small jeweler's file quickly had things moving quite smoothly.

I seriously doubt you'll ever regret this one. You'll certainly be nicelyy surprised by how much added capability you've gained.

Steve
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: bogstandard on March 29, 2009, 10:43:33 PM: Nice work David.

The confidence to do things like this gives you greater scope in getting your little basic lathe into a much more versatile machine. A tweak here and a fiddle there will make it into a totally different machine from basic.

Don't let how tut-tut's do things stop you from doing what YOU want to do, ie tailstock centre. If it works for you, use it, you are the one doing the job, no-one else.

As long as you are not creating a safety issue by doing it, then it is OK.

John
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: sbwhart on March 30, 2009, 03:55:51 AM: Well done that man :clap: :clap: :clap:

Using the centre when parting is OK I do it myselve from time to time when sercumstances demand it, you just have to be carfull at the last little bit I back the centre off to let the job drop away. :headbang: :headbang:

Have fun

Stew
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: Twinsquirrel on March 30, 2009, 02:31:52 PM: I'm glad you guys didn't shout at me for the live center/parting thing. I know it's silly but I'm a little wary of showing my setups sometimes in case I'm doing something stupid. I always think safety first though.

Darren,

This is the shaft that needs extending to accomodate the spacer.

(http://i294.photobucket.com/albums/mm108/twinsquirrel/29032009077.jpg)

Steve,

Am I right in thinking that you extended the threaded part of the shaft? I was thinking of just extending the non threaded part as I will not be fitting a bearing?
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: shoey51 on March 30, 2009, 04:28:16 PM: great job there Steve
I wouldnt be game to do that to mine
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: Twinsquirrel on March 30, 2009, 04:39:10 PM: Shoey,

Nothing ventured nothing gained eh? He who dares, wins Rodney.

David
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: cedge on March 30, 2009, 05:23:51 PM: TS...
The shoulder flange of the lead screw goes between the old and new parts. You'll want to add on to the threaded end.

Steve
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: Twinsquirrel on March 30, 2009, 05:28:03 PM: ah I see, I've counterbored the new spacer to keep the shoulder in its original position, I thought this might work?

David
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: cedge on March 30, 2009, 08:05:19 PM: David
Seems like a lot of work to reach around one's thumb to touch one's elbow...(grin). The mod has been successful untold numbers of times. Reinventing the wheel seems a little like a lot of work only to get unproven results.

Steve
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: Twinsquirrel on March 31, 2009, 03:18:36 AM: Noted Steve, I have ordered a new screw but in the meantime I may have a go with my original idea as I can easily change tack if it all goes south.

I guess Im just a rebel without a clue :hammer:

David
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: winklmj on May 18, 2010, 02:14:11 PM: So how'd it go with this mod. I've started a similar mod this weekend. I'll be adding a ball-bearing as well similar to the mod on GadgetBuilder's site.
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: Sorekiwi on May 18, 2010, 09:15:32 PM: Its been 4 or 5 years since I did this same mod on mine, so the details are a little "fuzzy". But I think I left the leadscrew in its origional location, and turned up an extension for the unthreaded end of the screw. I also added a ball bearing in the extension spacer.

I could go out to the shed and look at the lathe, but its cold and raining tonight, and I think there are monsters out there...
Title: Re: Extending the cross slide travel on a 7 x 12 mini lathe
Post by: andyf on May 19, 2010, 02:44:53 AM: There's another, very similar, recipe for extending the cross-slide travel on here:
http://mikesworkshop.weebly.com/cross-slide-extended-travel.html
by Mike Cox, who had the idea for the swing-up toolholder for threading. At the end, he reckons it could have been done without milling out the slide. There's a mod for extending the top-slide travel on there, too.

Mike has only just started his site, but it will be worth keeping an eye on it if you are into improving your mini-lathe; I know there are things like a T-slotted cross-slide to come.

Andy