Mellor lathe.

[Pete.]

I found the 20. 25.
Two 20s and a 32 in the tumblr.
One 20 on the spindle.
A 63 rear screw gear and a couple more I need to take cover off to count. Gears everywhere

Well, going by your screwcutting chart you have an effective 4tpi leadscrew (because 4TPI has the same input and output gears sizes), which is 6.35mm lead. To get your metric pitch you look at the letters of the gears in the inch chart and use the formula:

6.35 x A ÷ B x C ÷ D = metric pitch in mm

Sorry about the edits I got myself mixed up with the symbols

 

[zx9]

@spencer 427 There are two change wheel calculator programmes taken from the Drummond Yahoo site, the site is a pain to navigate so I have put the least clunky one in the public area of my Drop Box.

https://www.dropbox.com/s/a4qjrga91yb9xwp/_NthreadP.exe?dl=0

Your security software will tell you not to run this .exe file, I have ran it with no ill effect but up to you to decide what to do.

Here is a link to an on line calculator http://bilar.co.uk/cgi-bin/change-gear-calculator.pl which gives simple and compound gear changes. They are worth playing with just to get an idea of how change wheels work.
Obviously if you do run these gear sets try them out on some scrap bar first.

 

[God mode restorations]

@spencer 427 There are two change wheel calculator programmes taken from the Drummond Yahoo site, the site is a pain to navigate so I have put the least clunky one in the public area of my Drop Box.

https://www.dropbox.com/s/a4qjrga91yb9xwp/_NthreadP.exe?dl=0

Your security software will tell you not to run this .exe file, I have ran it with no ill effect but up to you to decide what to do.

Here is a link to an on line calculator http://bilar.co.uk/cgi-bin/change-gear-calculator.pl which gives simple and compound gear changes. They are worth playing with just to get an idea of how change wheels work.
Obviously if you do run these gear sets try them out on some scrap bar first.

Thanks ZX9. Will give them a look.

 

[Pete.]

Spencer you'll remember the trick I showed you of making your first threading pass with a magic marker held against the tool holder just touching the part.

 

[God mode restorations]

Spencer you'll remember the trick I showed you of making your first threading pass with a magic marker held against the tool holder just touching the part.

I do Pete indeed. I will be experimenting with the screw cutting very soon.

 

[Richard.]

I love thread cutting on the lathe. There is something incredibly satisfying when you remove the part to find your thread works spot on with its marrying side.

 

[God mode restorations]

There is one little part of the machine that's bugging me. I am not trying to find stuff to do but have to double check everything. Information and pictures of Mellor are limited and it's difficult to work out if something is missing . At the end of my headstock spindle there is a free race bearing that sits on a cup. The bearing and cup are in perfect condition but i think something is missing .Will post some pictures

 

[Seadog]

I love thread cutting on the lathe. There is something incredibly satisfying when you remove the part to find your thread works spot on with its marrying side.

On Thursday I saw the lead screw you made for Spencer, Richard. A very nice job, I must say. Very little backlash too. I've yet to cut a parallel thread, I've only machined standard threads and a B&S worm for a rotary table that I reconditioned.

 

[Richard.]

On Thursday I saw the lead screw you made for Spencer, Richard. A very nice job, I must say. Very little backlash too. I've yet to cut a parallel thread, I've only machined standard threads and a B&S worm for a rotary table that I reconditioned.

Pete made Spencer’s lead screw. I certainly ain’t that good.

 

[Seadog]

Pete made Spencer’s lead screw. I certainly ain’t that good.

Whoops! Nice job @Pete.

 

[Richard.]

Whoops! Nice job @Pete.

More than happy to take the credit though

 

[zx9]

I love thread cutting on the lathe. There is something incredibly satisfying when you remove the part to find your thread works spot on with its marrying side.

That first blind internal thread I posted was ecstatically satisfying, especially as I could not check my progress without removing it from the chuck.

 

[Richard.]

I’ve cut a few internally. It’s always my preference to cut or have the external one to hand first so I can check it’s gonna go before disengagement of the half nuts or removal from the chuck.

 

[God mode restorations]

Here is a few pictures of the headstock rear spindle bearing and cups. The cup that sits inside the tumbler housing just sits there. I would of thought it would of sat snug inside the housing.

 

[God mode restorations]

New pulley arrived today. A bit of a faf changing belts but all sorted. Loads better and it's running really nice now.

 

[addjunkie]

Your lathe looks clean and shiney, but a little lacking in the oil on the silver bits....or is it just very clean thin oil you use

 

[God mode restorations]

Your lathe looks clean and shiney, but a little lacking in the oil on the silver bits....or is it just very clean thin oil you use

It's probably the lighting. I oil all the ways every time I turn it on. And all the other parts.

 

[God mode restorations]

Today's the day that I am attempting to actually start making bits. Will let you guys no my results and how it goes

 

[Richard.]

Try your hand at threads spencer.

 

[God mode restorations]

Try your hand at threads spencer.

Will do Richard .Am out this morning picking up fresh mild steel. I brought a big box of off cuts ages ago. But didn't realise they are some sort of hardened chromoly. I did a file test on em and it laffed at the file