# Craftex 7x8 Lathe



## gwapoboy (Dec 23, 2014)

Hey everybody, picked up a Craftex mini lathe today its the 7x8 one thats on sale right now for 575. What I was wondering is what mods you guys suggest I do to it to make it better?(Might try and upgrade the motor one day).

Oh ya, I mainly plan on machining, Aluminum, Delrin, and cold rolled steel, and maybe and i do mean maybe stainless steel


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## vederstein (Dec 23, 2014)

When I had a mini-lathe, I made the following mods (in order of usefulness):

1. QCTP
2. Camlock tailstock
3. Affixed a dial indicator to the crossfeed.
4. Carriage Stop


...Ved,


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## canadianhorsepower (Dec 23, 2014)

vederstein said:


> When I had a mini-lathe, I made the following mods (in order of usefulness):
> 
> 1. QCTP
> 2. Camlock tailstock
> ...



totaly agree
 1. QCTP from A2Z only the rest are WAY to big 
https://www.littlemachineshop.com/products/product_view.php?ProductID=2487&category=
 2. Camlock tailstock          availlable from  https://www.littlemachineshop.com/products/product_view.php?ProductID=2018&category=


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## gmac (Dec 23, 2014)

Starting point;

http://www.mini-lathe.com/Mini_lathe/Modifications/modifications.htm

http://www.toolsandmods.com/lathe

http://www.gadgetbuilder.com/MiniMods.html

Cheers Garry


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## chucketn (Dec 23, 2014)

I heartily recommend the OXA QCTP from Little Machine Shop(usual disclaimer, just a happy customer).  I have extended my cross slide travel, made a custom fine feed banjo, and added a T-Slot Cross Slide from LMS.
Soon, I will be replacing the stock motor controller with a treadmill controller. I think I will leave the stock drive including the motor on my 7x, but if the motor gives problems, I have a treadmill motor standing by...


Chuck


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## gwapoboy (Dec 23, 2014)

The thing also is the stock motor is 1/3HP would it be worth modifying it to a 1/2HP motor or even maybe a 3/4HP motor?


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## gwapoboy (Dec 23, 2014)

Would upgrading the motor be worth it? stock motor is 1/3HP bushed motor


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## gwapoboy (Dec 24, 2014)

Picked up a DRO Kit today from Busy Bee suppost to fit this model lathe, went to do the compound rest and the gib wont fit  So trying to figure out if its worth getting a custom gib made or if I should modify this gib as its 0.040"approx. difference


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## canadianhorsepower (Dec 24, 2014)

gwapoboy said:


> Picked up a DRO Kit today from Busy Bee suppost to fit this model lathe, went to do the compound rest and the gib wont fit  So trying to figure out if its worth getting a custom gib made or if I should modify this gib as its 0.040"approx. difference


 
 witch DRO did you get.... The igaging one I hope
 whats wrong with the GIB 
 where about in Canada are you

 cheers


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## gwapoboy (Dec 24, 2014)

canadianhorsepower said:


> witch DRO did you get.... The igaging one I hope
> whats wrong with the GIB
> where about in Canada are you
> 
> cheers



this one http://www.busybeetools.com/products/digital-read-out-for-metal-lathe.html 

Replaces two of the main screws, compound rest. and the Gib is two big to fit the new kit


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## canadianhorsepower (Dec 24, 2014)

gwapoboy said:


> this one http://www.busybeetools.com/products/digital-read-out-for-metal-lathe.html
> 
> Replaces two of the main screws, compound rest. and the Gib is two big to fit the new kit



There is one BIG SERIOUS ISSUE
they dont take into consideration your back lach in your lathe.
these are quad encoder reader. They count the step going up and going down to the turning of your handel. So if your lathe have 4 thou back lash it wont dee it:wall::wall::wall: you would be 100 time better with these
http://www.busybeetools.com/products/digital-remote-readout-0-6in-in-and-metric.html they do measure your movement and not the count of pulse. Some people don't like them:hDe: I do this is what I'm using on my Taig lathe
where are you in Canada ???

 beside you will save half the price Rof}Rof}Rof}


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## /// (Dec 24, 2014)

An even more insidious problem with the leadscrew type DRO's is that the backlash is not constant. You might measure the backlash as, say, 4 thou and add/subtract this figure. However, that figure will change depending on the quality of the leadscrew and where in the leadscrew's travel you are working, it may be 4thou in the middle of the leadscrew, 3 thou at one end and 6 thou at the other. Also, wear will change these figures over time.
Linear Scales are definitely the way to go.


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## TorontoBuilder (Dec 25, 2014)

gwapoboy said:


> this one http://www.busybeetools.com/products/digital-read-out-for-metal-lathe.html



That's the problem with Busybee, their employees are not brightest. They should not have sold you that DRO. No surprise tho, they shipped my lathe barely attached to two sagging rickety pallets so it toppled over.


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## Wizard69 (Dec 26, 2014)

gwapoboy said:


> The thing also is the stock motor is 1/3HP would it be worth modifying it to a 1/2HP motor or even maybe a 3/4HP motor?




This is a small lathe I can't see a reason to go to 3\4 HP, unless you wanted to upgrade to a 3Phase motor and a VFD.   Even then you would have trouble finding a place for the motor.   The reason you might do such a large motor is to get more torque at low RPMs making your range of speeds more useful.  

Given that a larger motor suggest more things to break if a stall condition is reached.  You will have to consider the negatives along with the positives.   The lathe might be able to use a 1/2 hp motor without being over sized but you still have the issue of where to put it.  

If I sound wishy washy here it is because not every machine is suitable for a power upgrade.  My father like to do such things like putting a 3HP motor on a tiny contractors saw.   Sometime excessive HP is just scary.   Your best bet is to search the net and see if anybody has actually done such an upgrade.


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## gwapoboy (Dec 26, 2014)

Wizard69 said:


> This is a small lathe I can't see a reason to go to 3\4 HP, unless you wanted to upgrade to a 3Phase motor and a VFD.   Even then you would have trouble finding a place for the motor.   The reason you might do such a large motor is to get more torque at low RPMs making your range of speeds more useful.
> 
> Given that a larger motor suggest more things to break if a stall condition is reached.  You will have to consider the negatives along with the positives.   The lathe might be able to use a 1/2 hp motor without being over sized but you still have the issue of where to put it.
> 
> If I sound wishy washy here it is because not every machine is suitable for a power upgrade.  My father like to do such things like putting a 3HP motor on a tiny contractors saw.   Sometime excessive HP is just scary.   Your best bet is to search the net and see if anybody has actually done such an upgrade.



Thanks for the reply, They say its a 7x8 but its more like a 7x10(Might get the 7x14 bed upgrade kit from LMS one day). I also have a mini mill and done have a huge amount of space, plus its the perfect size for what I mainly machine(Aluminum and Delrin).  

Also Returned the DRO kit today with no issues. And purchased some tooling. Thinking Ill need to order Imperial conversion kit from LMS if the kit will kit.


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## gwapoboy (Dec 27, 2014)

So what kind of mods will make the lathe more accurate and more sturdy? P.S. Cost isnt that important tbh plan on putting a decent amount of cash into getting all set up


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## chucketn (Dec 27, 2014)

Look into tapered gibs for the saddle. That will improve the stability of the saddle. That's the only mod I can think of for rigidity. Most mods are to increase functionality or capacity.

Chuck


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## gwapoboy (Dec 27, 2014)

chucketn said:


> Look into tapered gibs for the saddle. That will improve the stability of the saddle. That's the only mod I can think of for rigidity. Most mods are to increase functionality or capacity.
> 
> Chuck



Thanks for the reply, I will have to look into that for sure. Only issue I think I will run into is the Gibs on my lathe I dont think are the same as what usually on a 7x lathe. Anybody have measurements of there gibs by any chance so I can see if mine are the same?


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## bazmak (Dec 27, 2014)

Hi i did a thread on a linishing mc and making new brass gibs without a mill
I gave all the dims both existing and new.I found it very easy.Regards barry


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## Dunc1 (Jan 20, 2015)

The British magazine Model Engineers Workshop produced a series of articles on the mini-lathe. You can read or download part 1 from www.arceurotrade.co.uk. Scroll down the page and click on Projects and Articles. Scroll down again to The C3 Mini-Lathe Part 1.

The articles referenced above were collated into a book by the original author, Dave Fenner - Workshop Practice Series #43, The Mini-Lathe.
This author also wrote Workshop Practice Series #48, Mini-Lathe Tools and Projects. They are available (maybe in stock) at Busy Bee or online at Amazon or Chapters.

The Home Shop Machinist has been running a series by Ted Hansen called Additions and Modifications to the Mini-Lathe. Busy Bee might have but Chapters, for sure.

The usual disclaimers.


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## Theclockworks (Jan 21, 2015)

First thing I would do is check the machne over every nut and bolt the guy that made mine must have had very sort spanners every thing need nipping up get a good quality chuck,change the jib strips and fit DRO,last I would fix in place once centerd the tailstock unless you're going to do any tapper turning with it. But most of all have fun they're capable little machines when sorted. P.S most come out of the same factory in different colours with numerous name badges


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## Nitrous (Feb 2, 2015)

canadianhorsepower said:


> There is one BIG SERIOUS ISSUE
> they dont take into consideration your back lach in your lathe.
> these are quad encoder reader. They count the step going up and going down to the turning of your handel. So if your lathe have 4 thou back lash it wont dee it:wall::wall::wall: you would be 100 time better with these
> http://www.busybeetools.com/products/digital-remote-readout-0-6in-in-and-metric.html they do measure your movement and not the count of pulse. Some people don't like them:hDe: I do this is what I'm using on my Taig lathe
> ...



The point about back lash in (most) rotary encoders is true, but I understand that this is acceptable due to the nature of manual lathe work. I.e. You always take up the back lash in approaching the cut. 

That said, the iGaging linear scales from Busybee and others aren't particularly accurate. I doubt 100 times would be the improvement in accuracy. 

There are some interesting websites looking at improving accuracy: Yuritoys is worth a look. I've found a source for reasonably accurate magnetic scale tape (at a decent price). A high resolution I.e. 12 bit linear encoder module can be had for less than $20 per head, plus mounting. Making up a decent quadrature encoded magnetic scale shouldn't be too difficult. 

Take a look here for the android DRO project. http://www.yuriystoys.com

Doug


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## canadianhorsepower (Feb 2, 2015)

> That said, the iGaging linear scales from Busybee and others aren't particularly accurate. I doubt 100 times would be the improvement in accuracy.
> 
> 
> 
> ...


Sorry Doug but I don't agree. I have that type of scale on my Taig lathe and love them.  THE problem is because they are cheap people
usually make bad instalation. They simply don't take time to measure that the max deflextion is .001 the total lengh. The fact that the scale are narower
then a Sino, Acutrack and other well known DRO makes it worst. anything longer then 6inch need a support in the middle  to make sure
that it does not flex
I would sugest them anytime


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## Nitrous (Feb 2, 2015)

canadianhorsepower said:


> Sorry Doug but I don't agree. I have that type of scale on my Taig lathe and love them. THE problem is because they are cheap people
> usually make bad instalation. They simply don't take time to measure that the max deflextion is .001 the total lengh. The fact that the scale are narower
> then a Sino, Acutrack and other well known DRO makes it worst. anything longer then 6inch need a support in the middle to make sure
> that it does not flex
> I would sugest them anytime


 
I believe you're talking about sine error which is a fact regardless of what linear scale you use. But the quoted specs for iGaging are not great, especially in the context of a lathe.

Description (from the iGaging site)
*Accuracy*: *±0.002&#8221;* per *6inch* *Repeatability*: *0.001*&#8221;
Battery: 3V CR2032 / Environmental Friendly
Reading: 0.001&#8221; / 0.01mm / inch fractional

If +/- 2 thou with a repeatability of 1 thou is good enough, no problem but I don't believe that the statement "100 times better" is anywhere near close to true. The usability of the rotary encoder on a lathe presupposes that the gross backlash in the screws are taken care of by the nature of dialing into the cut, rather than the idea that most machinists dial in AND out of a cut. 

Admittedly, there is a "better" grade of iGaging (previously it was "AccuRemote Digital" but that has been discontinued and replaced with a much more expensive iGaging Absolute) but the price is double or more what the DigMAG versions are priced at.

iGaging ABSOLUTE specs



*0.0254mm/0.001in over a 150mm/6in range*
0.0381mm/0.0015in over a 300mm/12in range
0.0508mm/0.002in over a 610mm/24in range
That's twice the accuracy of the regular iGaging products


Anyway, if you're happy with it, that's all that counts, right? 

Doug


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## canadianhorsepower (Feb 2, 2015)

Nitrous said:


> Accuracy[/B]: *±0.002* per *6inch* *Repeatability*: *0.001*
> Anyway, if you're happy with it, that's all that counts, right?
> 
> Doug


  Hi Doug
*Accuracy*: *±0.002* per *6inch* *Repeatability*: *0.001*

I think it is acceptable cause it's over inch and being on my taig
there is nothing bigger then 3inch on it.

even on my Seig or my 13x36 my mill that have  Mitutoyo  I don't
trust them for the finish I will reset everything with what my micrometer would read

cheers

Luc


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## Nitrous (Feb 2, 2015)

I have a compact 5 and a Craftex 7x that I'm looking at putting magnetic scales on.
I have the DigMAG by iGaging, but I am interested in finding a cheap, Magnetic Scale source.

I used to think that rotary encoders have no value in Lathe work but I did a little research looking into it.
There are rotary encoders that strictly go onto the screw. Certainly accuracy there needs addressing at the operator level. But 2 thou over six inches doesn't mean 1/6 x 2 thou over 1" when dealing with smaller parts  Accuracy, Resolution and Precision all come into play here.  

There is a Canadian solution that actually is a combination of a linear encoder coupled with a rack and pinion assembly. They basically eliminate backlash at the pinion gear level. Not sure if it's simply due to preloading the gear to the rack or if they actually use something like a split pinion gear. 

My luck changed when I sourced (~$30/metre) Bogen-Electronics 1mm pitch magnetic scale material. Close to glass in terms of accuracy but with costs many times lower. 

Doug


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