7x14 to 7x16 Rebuild

[dabear3428]

I am literally extending the backsplah backwards enough to allow "easy removal" of the cross slide without removing the feedscrew or carrier boss. (hassle, bearings etc).

The "trap door" in the bottom of the backsplash below the rear of the ways will drop into/onto a high angle slope (45 degrees or more) of sheet steel that slopes straight into the chip tray. It will be hinged from below and have a perimeter layer of neoprene to stop "dribbles" of cutting oil. Also planning on a Q/R system for the trap door, something like a quarter turn fastener.



There are more limitations in the pee-poor engineering. The lack of bearings in the leadscrew, the lack of rearwards cross slide travel, the lack of bearings to the cross or top slide feedscrews.

The lack of rigidity can be countered to a small extent with certain methods, but it will always be "noodle like" no matter what is done.

have you thought about raising the lathe bed?

 

[GrifterGuru]

have you thought about raising the lathe bed?

It is already at a perfect working height and I do not have the vertical space to lift it. It literally sits directly under a double kitchen cabinet and to say there is litterally a 1/4" gap between the top of the speed control knob and the underside of the cabinet is being generous!

I literally unbolt it and slide it back to the wall hen I am not using it. I don't have much other choice.

 

[dabear3428]

Wow now that is tight and what works for me would not work for you

 

[GrifterGuru]

Yup, it is tight. 1/4" clearance above and 3" clearance off the t/stock end of the bedway when shifted all the way to the left in the space I have.

 

[dabear3428]

Yup, it is tight. 1/4" clearance above and 3" clearance off the t/stock end of the bedway when shifted all the way to the left in the space I have.

My hat is off to you, i cannot even think in a space that tight, not to mention i would have to control my clutter tendency's. as it is now when i run out of space i suffer the wrath of the SO and have more conditioned space added inside my shop.
my solution the last time was to tell her just think of all the unused storage space she would have in the loft above (12' eves in my shop).

 

[SouthernChap]

I have to ask, at this point would it have been better to custom build a lathe from scratch?

Even if we're talking about a small 7 x 14 lathe, most people wouldn't have the facilities or indeed, the skills to cast a bed in cast iron.

Most would struggle with a headstock. I mean, as an alternative to casting, you could get a headstock sized chunk of cast iron and mill it out, but even for someone with a good sized mill, (something like an Adcock and Shipley, an Elliot or a Bridgeport) that's an awful lot of work; casting would be more doable I'd think but yeah, that again requires skills and facilities many don't have.

Saddle, cross slide and top slide would be within the reach of a decently equipped workshop but then, if someone has a decently equipped workshop, they don't really need to build a 7x14 lathe.

Okay, so you think about buying used 'old US/English iron' major parts (bed, headstock, tailstock, etc.) from people who are parting out and make the rest yourself (you obviously have at least a lathe of some sort already; even someone handy with their benchwork skills is going to be challenged making an acme threaded leadscrew, 20 plus inches long with a hacksaw, files and a vice)

If the parts are from a reputable make of small-ish lathe (Boxford, Myford, South Bend, etc.), the parts will be expensive enough that you might as well buy a used intact lathe.

Then there's the space factor. Something which @GrifterGuru has to deal with.

Sure, there's the teensy watch-maker's lathes like Cowells et al. but they're even more limited than a 7x14 and expensive. I guess one of the Hobbymat/Prazimat lathes would have been a start point further along the line, but they're oddly not that common in the UK (although in the last month or so a couple of apparently decent examples have popped up on FBM and eBay; they were gone pretty quick mind you)

The average Chinese mini lathe's flaws are manifold and well documented but most are possible to overcome to some degree or at least mitigate. Most importantly, it does just creep into that sweet spot in terms of just being big enough (and given the kind of work @GrifterGuru is putting in, the capability) to do useful general lathe work on, but not so big that where space is at a premium, you can't fit it in.

With a bed that notionally allows 16" between centres as opposed to the more common 14" @GrifterGuru is getting the most out of this small form factor (IIRC he's also mentioned he has managed to squeeze out every last bit of work envelope out of that 16").

My efforts (clumsy and lacking in skill as they are) to make a silk (or at least cotton) purse out of the pigs ear of my mini lathe are the result of me buying a mini lathe due to ignorance and impatience and honestly filling out the time before I can buy something bigger and better (and I've enjoyed myself and learned a lot too). I can fit something like a Colchester Bantam or Boxford in my workshop, I just can't afford to yet (partly because I've spent too much on the resources necessary to rebuild this slightly scrappy Chinese midget!).

@GrifterGuru is doing it because it's probably the sanest course given the space he has.

If I was to go back in time, I'd be patient and snap up the first decent Boxford A or B I saw (or maybe a C at the right price).

If @GrifterGuru had a time machine, given the space he has, maybe he'd look for an Emco Compact 5 or a Hobbymat MD65/Prazimat DZL but eh, we're all prisoners of the arrow of time and I bet he's had a blast working on his 'Chinese midget'.

 

[RaisedByWolves]

I am.

But I also accidentally hit 'post' too soon and so I've edited my post now to add all the rest of the waffle I wanted to add.

Mmmmm, waffles! Do you guys have them over there?

like i said your toys your money, your time and it is never waisted if it is what you want, and just because i cannot see the reason does not mean you don't have 1, but for the life of me i cannot see it (again, i do not need to).

Maybe I can give some insight.

On a direct drive lathe of this size 1.5HP really is not out of the question. The issue comes in with low speed torque. With a DD lathe you need more mass in the windings to offset the heat buildup when running down at low speeds.

On My SD400 I'm keeping the belt reduction and going with a higher HP motor for a variety of reasons along with the heat issue. Im used to 7HP lathes with a low speed of 30ish and mountains of torque for performing certain tasks. Mush safer (Tooling wise) to be able to pull up low speed/high torque when you need it that to be stuck having make do.

I think when I cross multiplied, divided and carried the one and all, I came up with a low speed of 3.5rpm and a high speed of 5000 with the CC motor and 12 sheeve steps over 3 sheeves.

Should be OK.

 

[RaisedByWolves]

DUPLICATE POST ADMIN PLEASE REMOVE

Best way to get this done?



POST BOOBS!

 

[RaisedByWolves]

If GrifterGuru had a time machine, given the space he has, maybe he'd look for an Emco Compact 5 or a Hobbymat MD65/Prazimat DZL but eh, we're all prisoners of the arrow of time and I bet he's had a blast working on his 'Chinese midget'.

Why I say my good dude, you @Ed him 87 times in one post, he's probably in need of a pint right now.


As to the quoted post, yeah, look how well that turned out for me a few times.

 

[dabear3428]

Even if we're talking about a small 7 x 14 lathe, most people wouldn't have the facilities or indeed, the skills to cast a bed in cast iron.

Most would struggle with a headstock. I mean, as an alternative to casting, you could get a headstock sized chunk of cast iron and mill it out, but even for someone with a good sized mill, (something like an Adcock and Shipley, an Elliot or a Bridgeport) that's an awful lot of work; casting would be more doable I'd think but yeah, that again requires skills and facilities many don't have.

Saddle, cross slide and top slide would be within the reach of a decently equipped workshop but then, if someone has a decently equipped workshop, they don't really need to build a 7x14 lathe.

Okay, so you think about buying used 'old US/English iron' major parts (bed, headstock, tailstock, etc.) from people who are parting out and make the rest yourself (you obviously have at least a lathe of some sort already; even someone handy with their benchwork skills is going to be challenged making an acme threaded leadscrew, 20 plus inches long with a hacksaw, files and a vice)

If the parts are from a reputable make of small-ish lathe (Boxford, Myford, South Bend, etc.), the parts will be expensive enough that you might as well buy a used intact lathe.

Then there's the space factor. Something which @GrifterGuru has to deal with.

Sure, there's the teensy watch-maker's lathes like Cowells et al. but they're even more limited than a 7x14 and expensive. I guess one of the Hobbymat/Prazimat lathes would have been a start point further along the line, but they're oddly not that common in the UK (although in the last month or so a couple of apparently decent examples have popped up on FBM and eBay; they were gone pretty quick mind you)

The average Chinese mini lathe's flaws are manifold and well documented but most are possible to overcome to some degree or at least mitigate. Most importantly, it does just creep into that sweet spot in terms of just being big enough (and given the kind of work @GrifterGuru is putting in, the capability) to do useful general lathe work on, but not so big that where space is at a premium, you can't fit it in.

With a bed that notionally allows 16" between centres as opposed to the more common 14" @GrifterGuru is getting the most out of this small form factor (IIRC he's also mentioned he has managed to squeeze out every last bit of work envelope out of that 16").

My efforts (clumsy and lacking in skill as they are) to make a silk (or at least cotton) purse out of the pigs ear of my mini lathe are the result of me buying a mini lathe due to ignorance and impatience and honestly filling out the time before I can buy something bigger and better (and I've enjoyed myself and learned a lot too). I can fit something like a Colchester Bantam or Boxford in my workshop, I just can't afford to yet (partly because I've spent too much on the resources necessary to rebuild this slightly scrappy Chinese midget!).

@GrifterGuru is doing it because it's probably the sanest course given the space he has.

If I was to go back in time, I'd be patient and snap up the first decent Boxford A or B I saw (or maybe a C at the right price).

If @GrifterGuru had a time machine, given the space he has, maybe he'd look for an Emco Compact 5 or a Hobbymat MD65/Prazimat DZL but eh, we're all prisoners of the arrow of time and I bet he's had a blast working on his 'Chinese midget'.

I agree with all of the above, please do not take my input as derogatory in any way. it is all fun in the end and it is not like any of us are trying to feed our families with the output of our shops, these are hobby activities and enjoyment/learning are the payoff not $s.
my question was, asking the OP if HE thought, not me trying to make that determination for him or what anyone else that has not done this to this level, thought , it is not up to me and should not be. as someone that has similar tendencies, i'm interested in his opinion about this approach to this project after he has done all of this work, again not saying anything just asking what the OP thinks about his project so far.
BTW i do not have any suggestions about how to do it better, because i do not know how to do this better. i guess i'm asking about lessons learned in this process.