Feeling a little restricted.

[Pete.]

Ok no bother, you have a 3mm leadscrew if that is your chart.

The stud gear is 25, so looking at the 3mm pitch gears you have 55 and 60 idlers and a 25 end gear on the screw. That's a 1:1 ratio with the spindle (idlers don't count in the train they an be anything that fits) - so the screw is 3mm.

 

[Pete.]

BTW if you look at the imperial chart you'll notice that all of the C gears are 63 teeth. This is what gives your translation from metric, though to be perfect it would be 63.5. It's plenty good enough for fasteners but I wouldn't go turning any leadscrews with it

 

[Richard.]

BTW if you look at the imperial chart you'll notice that all of the C gears are 63 teeth. This is what gives your translation from metric, though to be perfect it would be 63.5. It's plenty good enough for fasteners but I wouldn't go turning any leadscrews with it

Ah yes so it is. I'm only really interested in the metric threads which as its a metric lathe with metric lead screw it looked like I'm well "geared" up to do it.

 

[Richard.]

I would guess if it was an imperial lathe Id need the 63 to cut metric threads then.

 

[Pete.]

Yup, or another translation set. There are several but only 127 teeth is perfect. I just paid a ridiculous amount of money for a set for my lathe - much more than the lathe cost actually.

 

[Richard.]

Yup, or another translation set. There are several but only 127 teeth is perfect. I just paid a ridiculous amount of money for a set for my lathe - much more than the lathe cost actually.

Yeah they are a lot of money especially in single items. If I was to buy all mine new it would probably be close on the lathe value too.
Looking at that chart again Id only need the 63 and 80 to complete the set for all those imperial threads too. Food for thought as they are easily obtainable.

 

[addjunkie]

The only imperial threads youll probably ever need unless your into restoration is bsp etc for pipe fittings when making your coolers etc.

If your making both parts you can use any thread that takes your fancy, it doesnt really matter so long as it works.

For example the last steering stem i made for a bike project has a pipe thread as it was near enough the right size, i had a die to polish it after machining, and was making all the bits, lock nuts etc. Works a treat, but pitty anyone trying to buy replacment parts in years to come.

Trust me, im an engineer this machining lark is far easier to learn than tig, but with screw cutting there is some timing and technique to master as matt mentions at the top of this page.

 

[Richard.]

Neither one GTAW or skillfull turning is harder to master than one another. It's down to how the individual takes to it. I've been turning for about the same length of time Matt has been welding and his progress is moving further forward than mine.

 

[MattH]

Neither one GTAW or skillfull turning is harder to master than one another. It's down to how the individual takes to it. I've been turning for about the same length of time Matt has been welding and his progress is moving further forward than mine.

I don't know about that, it was yeas before I started thread cutting. You seem to be cracking on.

 

[Chris Stevens]

I don't know about that, it was yeas before I started thread cutting. You seem to be cracking on.

I have owned a lathe for 5 years, and am still very much a beginner grappling with the basics...............very envious of anyone able to master thread cutting within a few days.

 

[Richard.]

I don't know about that, it was yeas before I started thread cutting. You seem to be cracking on.

Having a crack at it and been successful are very different things. Your Alu welding is coming on nicely. I've met, interviewed and weld tested a hell of a lot of "tig welders" in my previous line of work and you'd be presently surprised how many of them were below the standard of what has been shown in your pictures. We are talking guys that claim to hold codings or time served etc. Welders are one of the worst tradesman for over exaggerating there own skill levels which I've seen many times over. Don't get me wrong I've also worked along side guys that are simply fantastic skilled blokes but on the grand scheme of things your taking some nice big strides and walking the walk very well. Yes there are lots of techniques you need to fine tune like sorting out craters and controlling the pool expansion when things get hot at the very end of a run. But the fundamentals appear to be sorted (arc length, filling intervals, torch angle). And your applying them to joints which is another step forward.

 

[cocker]

Exactly what I've been doing. Cheers fellas. Need some tooling now mind and a DTI. Any links to either would be good as I don't want to be buying twice. Is it worth me buying the hss tools and leaning how to grind them up? Should learn about it really.

If you get some hss you will be able to grind up all sorts of tools .
Throwaway tip tools will be dearer but do what there made for very well .

 

[Chris Stevens]

A good universal tool for small lathes can be had from Eccentric Engineering, comes with jig for sharpening HSS tool bits, and can be used for threading as well as general turning. Tipped tools tend to work better on larger more rigid machines, at higher speeds. EE tool will do pretty much anything, and turning harder materials is no problem if you use Crobalt rather than HSS bits...................

http://www.eccentricengineering.com.au/index.php?option=com_content&view=article&id=2&Itemid

 

[MattH]

Crobalt. Does that have a curved blade type end on it?

 

[Brad93]

Yeah they are a lot of money especially in single items. If I was to buy all mine new it would probably be close on the lathe value too.
Looking at that chart again Id only need the 63 and 80 to complete the set for all those imperial threads too. Food for thought as they are easily obtainable.

Seen 63 tooth gears on ebay recently richard for not a lot of money.

 

[Brad93]

One of johns exellent videos with screw cutting via the thread dial on his harrison. Kicks off about 9:30

 

[roofman]

Exactly what I've been doing. Cheers fellas. Need some tooling now mind and a DTI. Any links to either would be good as I don't want to be buying twice. Is it worth me buying the hss tools and leaning how to grind them up? Should learn about it really.

Getting bagged tomorrow night mate and practice grinding on my ground stuff before buying new..btw what size does your tool post take,had that many lathes since my Myford ive forgot now

 

[gaz1]

full set for ml7

http://www.ebay.co.uk/itm/MYFORD-ME...581052?hash=item3f62af153c:g:1B4AAOSwxvxW7YjP

http://www.ebay.co.uk/itm/63T-CHANG...102322?hash=item3c9e31cfb2:g:YTcAAOxyCGNTOnBM

http://www.ebay.co.uk/itm/New-genui...hash=item2c8311439c:m:m7qT3FqRKv8sgAmDRkcSYOw

 

[gaz1]

Now for the fun bit......
Imperial, TPI = driven/driver x driven/driver x leadscrew TPI
Or:
Metric, Pitch = driven/driver x driven/driver x leadscrew pitch in mm.

Using the imperial as an example, and just guessing at what gears you have, if you fitted an 80t at the top, followed by a 25, then a 63 on the same shaft as the 25, driving a 80t gear on the leadscrew shaft, you would cut a thread tpi as follows:
Tpi = 80/25 x 63/80 x 8
Tpi = 20.16, ie 20.16 teeth per inch of thread, which converts to 0.794mm pitch
If you were shooting for a 0.8 mm pitch then you'd only be 6 thou out or 0.75% which would probably be fine for anything but the longest thread (certainly ok for a normal nut and bolt, or a plumbing fitting).

id love some extra info on my gearbox that i have posted on the forums if you could at all take a look

http://www.mig-welding.co.uk/forum/threads/myford-ml7-homemade-gearbox.56156/

 

[addjunkie]

A good universal tool for small lathes can be had from Eccentric Engineering, comes with jig for sharpening HSS tool bits, and can be used for threading as well as general turning. Tipped tools tend to work better on larger more rigid machines, at higher speeds. EE tool will do pretty much anything, and turning harder materials is no problem if you use Crobalt rather than HSS bits...................

http://www.eccentricengineering.com.au/index.php?option=com_content&view=article&id=2&Itemid

I liked those tools, thought ill treat my self, until i saw the price....ouch.