Author Topic: Top 10 mods for Mini lathe please ?  (Read 7115 times)

Offline Chilliphil

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Re: Top 10 mods for Mini lathe please ?
« Reply #25 on: December 03, 2016, 07:47:41 AM »
I hope you keep asking basic questions! I'm more of a newbie than you and am following this thread with great interest. Thanks to all contributors.

Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #26 on: December 03, 2016, 10:00:17 AM »
Only when we stop learning do we loose interest in life.
Had thought I would make some of these in Ali....or Am I just wasting my time and materials ? Also maybe the Engineers on here could explain the relief on the back, that goes around the shaft ?  I guessed it was so that any debris that does get past the plastic doesn't get jammed between the shaft and plastic....being that it's a larger space ? That's what I thought anyway.
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Offline Kjelle

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Re: Top 10 mods for Mini lathe please ?
« Reply #27 on: December 03, 2016, 03:53:32 PM »
Buell, check Arc' s site, they have instructions for this job there! I havn't done this conversion, but remember reading those files and thinking it can't be that hard to do this.

BTW, you riding a Buell?

Kjelle

Online mexican jon

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Re: Top 10 mods for Mini lathe please ?
« Reply #28 on: December 03, 2016, 03:57:44 PM »
People say you only live once ! I say thank F@*K can't afford to do it twice.

Offline John Rudd

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Re: Top 10 mods for Mini lathe please ?
« Reply #29 on: December 03, 2016, 04:01:13 PM »
Buell,
I did do a write up on changing the bearings on the minilathe when I did my C3, Ketan did ask if he could publish it in his website, not sure if he did...but I remember putting back the original bearing shields......
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Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #30 on: December 03, 2016, 04:12:35 PM »
Hi guys thanks for all the info and help ..much appreciated. I have seen lots of people do the conversion...with interesting tools and pullers and the like ! I have it all apart no issues at all just another strip down day. Think as I'm doing this I will try and make the plastic end caps in Ali...That is if I don't cock it up !

Yes Buell Xb1200 and Husqvarna Supermoto.

Just finished a few bits...needed something to do !
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Offline John Rudd

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Re: Top 10 mods for Mini lathe please ?
« Reply #31 on: December 03, 2016, 04:15:07 PM »
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Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #32 on: December 03, 2016, 05:41:46 PM »
Thanks very much that clears up and shines a light on some stuff.... But I'm still puzzled ! ...sorry

If we polish the journals so that it is a "hard hand push " to get the new tapered bearings on...then what's to stop me Pushing them even further with say an Even harder push with a Blunt drill in the tail stock . Yes I know that was a bit over bored but you get the idea. I'm not trying to be crazy about this but at what point do they stop Moving on the shaft ? We know that the original shaft was very tight and the new taper bearing will not go on this..so we polish and smooth and make it a firm fit but there is a part of me that is interested because if it does move backwards then gears and belts etc will be mis aligned  maybe ?  Is it just the mere fact that we have two Hard fitting bearings fitted that it's very unlikely to happen...

The new and the old bearings are after all the same dimension on the shaft...just we don't want them to fit as tight as before, because it could damage and preload them to much. I'm guessing here as I'm not an Engineer...Just a Heating One !

Ps if you say Enough...I will drop this !! :lol: :lol:
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Online mexican jon

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Re: Top 10 mods for Mini lathe please ?
« Reply #33 on: December 03, 2016, 06:14:46 PM »
The bearing need to be a sized fit  :scratch: this allows the nuts on the drive end to be tightened so as to put load on the bearings  :thumbup: the fact that the whole assembly is held together stops the possibility of any movement, the fact the inner races are also locked by the shoulders means that the shaft and bearings spin together. Simples  :headbang:
People say you only live once ! I say thank F@*K can't afford to do it twice.

Offline picclock

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Re: Top 10 mods for Mini lathe please ?
« Reply #34 on: December 18, 2016, 09:51:05 AM »
FWIW while you have the headstock off replace the speed change gears for metal ones. ARC will supply, though one of the ones I had from them was very poorly cast.

The other mod I found most useful was an additional gear reduction from the motor and belt replacement. This allows higher torque at the cost of lower speed, which I have found very useful.

Removal of the compound slide and replacement of it with a solid metal block also improves rigidity allowing better finishes and parting.

There is some other info and pictures which may (or may not) be useful on photobucket :
http://s917.photobucket.com/user/picclock/library/7x14%20Real%20Bull%20mini%20%20lathe?sort=3&page=1

Best Regards

picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #35 on: December 23, 2016, 12:21:38 PM »
Thanks for all the ideas and Info on this was a Great help.

So far Have replaced the Bearings with taper version..To be fair was Very easy, Only note was th use your instinct when putting the new races on the shaft. One of the journals was a slight different fit to the other so had to polish the faces as described just a little bit more. Only noticed this when it went easy over there outer journal then when it came to the One closest to the headstock was solid...So off it came and polish a little more./Guess if i had a Mic I might have noticed it.  I also made some replacements to the plastic outer race covers in ali. Anyway started to rebuild it and started with the adjustable gibs brackets etc.. Not going to plan. I ended up asking someone to make them up for me !! But when I got them I wasn't happy..Feeling fed up I went out and got a Mini mill  :hammer: Now if i could just work out how to Use this machine  :clap:  I know its throwing myself in at the deep end but have Set it up and Have to say first bit of the brackets is just great. I read somewhere to get the Taper correct there is a clever way or should i say Easy way ? My idea was to put a pair of parallel bars under the work piece and put a 1mm drill under one end to give the taper ? I have limited tooling jigs etc Honestly don't even have parallel bars at the Moment ! Any tips would be great. Did see a post By Spuddevans which was fab so basing it on that at the Moment.

Happy Xmas All
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Offline John Rudd

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Re: Top 10 mods for Mini lathe please ?
« Reply #36 on: December 23, 2016, 02:49:39 PM »
Great to hear you are making progress...

Take yout time and think about what you are trying to achieve.......

Best wishes  for the festive season...
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Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #37 on: December 27, 2016, 04:20:57 PM »
As its Xmas ...I get some time to play with My first mill. Having never used one before, the learning curve was somewhat steep. Today I spent some time Try to make the Gib brackets.. Go easy as everything here is my first attempt at working with Machining steel. Any comments welcome. I still have the gibs in bras to do which i feel will be even harder. The first pic is the Mistake..best to get that out of my system..just the wrong angle i choose  whoops !  :bugeye:
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Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #38 on: January 08, 2017, 01:30:54 PM »
I have finally got the brass gib strips done and the Brackets..But i have a question to all that have done this. Do the Adjustment screws tend to loosen as there is nothing to stop them unwinding ? My thought was to drill and tap a locking grub screw to lock the adjusting screw.. or is this Not needed ?

will post pics soon...If i don't mess it up at the end ! Still learning.
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Offline John Rudd

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Re: Top 10 mods for Mini lathe please ?
« Reply #39 on: January 08, 2017, 01:49:30 PM »
The gib strip adjusting screws should have lock nuts on them......thats what mine was like before and after modding...
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Offline John Stevenson

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Re: Top 10 mods for Mini lathe please ?
« Reply #40 on: January 08, 2017, 01:54:39 PM »
Just fit the one metal gear to the spindle as this is the hard one to replace if the original plastic one breaks.
Leave the lay shaft gear as plastic as if it shears it will protect everything else but be easy to change. Also has the advantage of being quieter than two steel gears.
John Stevenson

Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #41 on: January 08, 2017, 04:28:47 PM »
Sorry my mistake didn't make it clear... The adjustment screw here....do you think it needs a locking grub screw underneath on the Bracket  to stop it vibrating loose ?
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Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #42 on: January 25, 2017, 06:52:44 AM »
Need to replace the 80mm chuck as it didn't come with inside out jaws ...Unless I'm missing something ! Whats the biggest size sensibly you can fit ? I guessed 100mm but was wondering if You can fit a 125mm without damaging the electronics ? spoke to Arc they said 100mm max .. any Comments on this much appreciated before i spend my money !
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Offline John Rudd

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Re: Top 10 mods for Mini lathe please ?
« Reply #43 on: January 25, 2017, 07:23:27 AM »
The advice offered by Arc is to be heeded......Ketan ( the proprieter) has worked very closely with mini lathe manufacturing ( Sieg in this case) so knows the limitations.....both mechanically and electronic wise...
Personally if you feel you need to go to a chuck bigger than the 100 mm the mini lathe can comfortably accomodate, you have the wrong machine......

I have three lathes ( and I'm not bragging....some folk have even more..!!  :lol: ) a mini lathe that has the std chuck or can use an ER 32 collet system,  a Chester 9 x 20 biggest chuck is 125mm or can take ER32, and an SPG equivalent of the WM290.... That currently has 160mm chucks but looking to add 200's

All three have their respective purpose, small to big jobs when needed...
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Offline Buell

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Re: Top 10 mods for Mini lathe please ?
« Reply #44 on: February 06, 2017, 04:10:25 PM »
Have need of a Knurler ...so with that in mind was just wondering if anyone had bought one of the Chronos ones that says it can go unto 50mm for Ģ18.00. Seems to good to be true when the wheels alone would cost Ģ7.00. Im guessing the effectiveness of this tool is its rigidity. My holder is max 10mm Square. With this in mind I have thought of getting the Kit from Hemingway, but having never built a kit wonders just the Complexity of it ? so would welcome any advice on their kits as well. Many thanks in Advance
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Offline hanermo

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Re: Top 10 mods for Mini lathe please ?
« Reply #45 on: May 12, 2017, 12:35:34 PM »
When I was actively using the 7x ...
I put a 125 mm chuck, 4 jaw, 5", on it and never took it off.

Electronics and frame are not the issue at all.
Std bearings can take a 1000 kgf load, radially or vertically.
Thats how metal lathes must work.

The 7x was too small for me..
but was an excellent learning platform at low cost.

Offline hanermo

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Re: Top 10 mods for Mini lathe please ?
« Reply #46 on: May 12, 2017, 12:46:15 PM »
Btw ... fwiw ... as a funny anecdote ...
I know (he taught me a lot) the guy(s) (Mi***n who designed the HAAS St lathe series.

He put in the 800 kg steel bar, and then pushed the button to deliberately crash the lathe at 3000 rpm.
And ran for his life.
It was a test to validate safety, that nothing comes through the enclosure.
Nothing did, enclosure was bulged.

Video is restricted IP, I donīt have a copy, and could not post it if I had it.
The chuck, tools, stuff was destroyed.
Lathe was fine.
Same lathe was still running in production 12+ hours / day, some years later.
Have seen it, myself.

A heavy piece running high rpm has huge potential energy.
My ex-workplace, had a client with a mistake on a lathe with heavy workpiece.
After it perforated the roof above, it lodged into the next floors ceiling (no injuries).