lathe al 336 threading

[froggie]

I was all fired up to buy a new lathe money in hand ,but when I found out you have to take the end cover off to change some speeds decided to keep the one I have with the the norton box.My main work is restoring old engines and tractors .this involves a certain amount of thread work which is all imperial threads. With the norton box you only have to use two levers to access 40 thread pitches.The new al 336 it seems you have to take end cover off and change different gears for many pitches.If you are making say a petrol fitting with different threads each end ie 19 and 26 by adjusting the two levers on the norton box all done in seconds,job done in 10 to 15 minutes.To me the al 336 seems a step backwards so I will spend the money on something else. Froggie

[Stustoys]

You could always buy an imperial leadscrew to go with your new lathe.

There is a well known author who doesnt have much time for these new fangled gear boxs you speak of and says that they are a step backwards. He believes we should all be using change gears.

Stuart

[Dave J]

Mine has a imperial lead screw and you still have to change gears for different threads as seen in the photo. I would like to make another small gear box to save changing them and have been thinking more about it now CTC has cheap gear cutters.
http://www.woodworkforums.com/attachment.php?attachmentid=154159&stc=1&d=1290826380
Dave

[Stustoys]

Dave do you use a 120/127 gear to get metric?
I have a metric leadscrew. The gear boxes must be almost the same.(just the last two columns or maybe the plate is wrong lol, would be interested in seeing the rest of your metric plate Dave especially D4)
I would have thought if you get a lathe with a imperial leadscrew the gearing would be easier to set.

One of these days I'm going to take the gearbox off so I can count the teeth and work out all the ratios.

Stuart


oops forgot pic

[Dave J]

Sorry for the blurry picture.
http://www.woodworkforums.com/attachment.php?attachmentid=154172&stc=1&d=1290832023

Dave

[Stustoys]

At least your guys left out the non-metric metric ratios lol
Unless of course you want to cut a .5625mm pinch thread, C2.

Stuart

[froggie]

the al336 lathe i looked at had an imperial lead screw and the pictures posted seem to be from al335 or al336.as the z gear looks like the one you change.The norton box has been around for about 40 years or more on lathes such as Hercus ,sheriden .nuttal and many others and is fast and easy.The first lathe i had at 16 years old(1948)was an Advance 3 1/2 inch by 21 inch made in Melbourne sold by Alfred Stewart.This had a stack of gears to change for each pitch.It was great later on to graduate to a Hercus with power feed etc.Good to have other points of view.

[Dave J]

My lathe comes from Gasweld, it's not from H&F's.:no: They are similar in design but mine is a lot better finished and a different lever set up in the bottom box as well as a few other things.
I understand what your saying about the gear change and it is a pain to change in the middle of a job. One day I will get around to making a separate gearbox for it.
It seems we are stuck with it until the manufactures change it. I come from a manual change Hercus so it was a big step up.

Dave

[Roulston]

Hey Dave J, thanks for the PM, but I just don't get the chinese manufacturing business. As I mentioned in my mail, my new one is a Toolex from Gasweld and looks like yours other than the gear box looks like the Hafco model, four drums not two.

Yet they all have the same modle number on the front. CQ6230A. Just like this one: http://http://cgi.ebay.com.au/36-X12-GEARED-HEAD-METAL-LATHE-W-COOLANT-LIGHT-STAND-/270658395485?pt=AU_Hardware&hash=item3f047f5d5d#ht_750wt_1117 (http://cgi.ebay.com.au/36-X12-GEARED-HEAD-METAL-LATHE-W-COOLANT-LIGHT-STAND-/270658395485?pt=AU_Hardware&hash=item3f047f5d5d#ht_750wt_1117)

which has a buy now price of $3200, he sold one yesterday at auction for $2800. This front panel is like mine, just green like yours.

Tony

[Dave J]

That surprises me they have changed because they have sold this same type of lathe for around 15 years that I can remember.
Gasweld may have changed their supplier or the supplier has changed gear boxes. I haven't been in their for a few years so I will call in and have a look at what the Newcastle store stock is looking like these days.
The website has only just been upgraded and it is still showing a lathe like mine with the same controls.:?
https://www.gasweld.com.au/products/580713
$3195 for the lathe and $395 for the stand, I think it was around $3400 when I got mine for $3000 cash.
Other guys down south have tried to barter with the price but got no ware, but up here they seem to.

Dave

[19brendan81]

Dont mean to hijack the thread but I this query about my lathe that has confused me for a while. It has a metric leadscrew and a quick change gearbox to cut metric threads from .2 to 3.5mm. However, on the end of the lathe it also has a gear on a quadrant that you can shift in order to cut imperial threads from 8 - 56 TPI using the same quick change gearbox.

How does this work? Are the metric threads accurate and the imperial threads an approximation?

[Gavin Newman]

Dont mean to hijack the thread but I this query about my lathe that has confused me for a while. It has a metric leadscrew and a quick change gearbox to cut metric threads from .2 to 3.5mm. However, on the end of the lathe it also has a gear on a quadrant that you can shift in order to cut imperial threads from 8 - 56 TPI using the same quick change gearbox.

How does this work? Are the metric threads accurate and the imperial threads an approximation?

What happens is that there is usually a 127/120 tooth or 127/100 compound gear that gets introduced into the power train, this has the effect of introducing some permutation of a 25.4 ratio into the gear-train (as in 25.4 mm = 1") which allows you to cut threads of the opposite system. Some lathes have a 63/50 gear which is not quite 25.4 but close enough for most purposes.

The downside is that the thread chasing dial will no longer work in this mode and so the half-nuts can't be disengaged between passes. The lathe needs to be stopped and reversed back between passes with the half-nuts engaged the whole time.

[Stustoys]

Dave Surely the gearboxs for USA lathes would be set for imp threads. I wonder how hard it would be to get hold of one of those?

Brendan Got a picture of the gearbox?

[19brendan81]

Here is a pic from the manual.

Thanks for the info Gavin.

[Stustoys]

Brendan, It looks like you have an 81 speed gearbox, Daves and mine only have 50 speeds.

I think some of the threads of the "other" system will be approximations(if they were exact why have two leadscrews?), but without knowing the gearing its hard to be sure.

Stuart

[Dave J]

Dave Surely the gearboxs for USA lathes would be set for imp threads. I wonder how hard it would be to get hold of one of those?

Brendan Got a picture of the gearbox?

The US imported Chinese lathes this size are the same as mine with the imperial lead and cross slide screws and have the same set up with having to change Z or Z1 to get the required imperial threads.
The main difference over the metric for them, is the thread dial can be used for imperial threads and maybe closer tolerance on the imperial threads, not sure.
My manual states
Lead screw pitch = 8 TPI (3mm)
Cross screw pitch =10 TPI (2.5mm)
Tool post =10 TPI (2.5mm)

Dave

[19brendan81]

Yeah I spose it would have 81 speeds. Some of them arent in the manual though, so god knows what feed they would do. Probably some fraction of a mm that im never likely to use.

Do you guys ever have need for a thread that isnt within the range of your gearboxes?

[pipeclay]

You have 81 (speeds) or there abouts on a plate only,in reality you dont have that many at all.

[Stustoys]

Wow Dave that surprises me, I would have thought the US market would drive the gearbox ratios. I knew they were moving more and more towards metric, maybe they are there now for the most part? I have 3mm pitch lead, 2mm cross and tool.

Brendan there are alot of ratios that aren't in my manual either. Some of them may over speed things. Although I haven't seen a warning about this on new lathes, I remember the lathes at tech had a warning "do not engage course feed above xxxrpm". I haven't cut many thread outside the norm. I did cut one 4 tpi as practice for a worm gear to use on a dividing plate on my lathe change gears, but that's pretty much it.
As I said earlier I would like to have a look inside the gearbox one of these days as the manual is no help as to what's inside.

Stuart

[Dave J]

The thread I hear people in the US complaining about not being on these lathes is 11 1/2 TPI, some lathes have it and some don't. I haven't needed it, but they say their is a metric thread that is really close to it.

I will give you a link to some pictures of inside the gear box when their site is back up and running. The guy had a problem with the key being bent and it wouldn't change into some of the gears.

Talking about different lathes and gear boxes, the guy I bought the vise off had this lathe for sale.
Do you guys think this lathe has had the apron and the gear box machined by the previous owner? or do you think it come like it from the factory?
I have seen the top of the carriage left with a machined surface on some lathes, but never the apron and gear box.:? I wonder if the lathes these days would be without any imperfections under the paint like this one.
HERLESS 12 inch SWING X 36 inch BC METAL LATHE CQ6230 (eBay item 170568760795 end time 28-Nov-10 20:00:00 AEDST) : Industrial (http://cgi.ebay.com.au/HERLESS-12-inch-SWING-X-36-inch-BC-METAL-LATHE-CQ6230-/170568760795?pt=LH_DefaultDomain_15&hash=item27b6b0bddb)

http://www.woodworkforums.com/attachment.php?attachmentid=154383&stc=1&d=1291008837
Dave

[Stustoys]

lol strange indeed Dave. I guess someone had his reasons. I wonder if someone way halfway through rebiulding it? The circle in the paint around the chuck shows that its been repainted.

Stuart

[franco]

Talking about different lathes and gear boxes, the guy I bought the vise off had this lathe for sale.
Do you guys think this lathe has had the apron and the gear box machined by the previous owner? or do you think it come like it from the factory?
I have seen the top of the carriage left with a machined surface on some lathes, but never the apron and gear box.:? I wonder if the lathes these days would be without any imperfections under the paint like this one.
HERLESS 12 inch SWING X 36 inch BC METAL LATHE CQ6230 (eBay item 170568760795 end time 28-Nov-10 20:00:00 AEDST) : Industrial (http://cgi.ebay.com.au/HERLESS-12-inch-SWING-X-36-inch-BC-METAL-LATHE-CQ6230-/170568760795?pt=LH_DefaultDomain_15&hash=item27b6b0bddb)

Dave

Dave,

My 1996 manufacture CQ6240 (ShaoXiang Machine Tool Co.) lathe, which is the 13X40 version of the lathe in your photo, also has the apron and threading gearbox face machined, so it is probably the standard factory finish for that time.

Frank.

[Dave J]

Thanks for that info Frank
It had me wondering if someone had done it.

Dave