Change gears and thread indicator for Steelmaster 1236A lathe

[Grahame Collins]

Hi guys ,

First up happy New Year to you all.

I am about to embark upon my first thread cutting adventure with my Steelmaster 1236A lathe (pictured.)

I have sorted the mysteries of the change gears and change gear table and worked out I’ll need a 48,,20 and 24 teeth train to give me 8 TPI

What I don’t follow is that there are three pinion options for the dial indicator unit (available with the change gear package) of 14 ,15 qnd 16 TPI..
I am not sure what to use?

I have downloaded some tables from practical machinist forum for this generic model but there was no mention of different pinions.
I have the standard tables as well as the Complete threading tables-81 pages of them!


Which pinion do I use and where on the eight divisions of the thread dial can I close the half nuts?


Before that though I will need to do some precision machining as I now have the D1-4 backing plate and the ER40 lathe adapter to mate together to gain use of the 23 piece ER40 collet set and dedicated spanner .
In the same purchase I got a 0- 16mm keyless chuck and MT-2 mandrel.

This was all for $364 AU delivered and arrived under 14 days over the Xmas period from Tools4cheap. I am really impressed with the service and quality of this bloke.


Thanks in advance.

Grahame

[Ueee]

Hi Grahame,
Do you have a metric or imperial lead screw? I get the feeling you will say Metric as you normally get more than one dial gear with them. If cutting imperial on a metric screw, you cannot use the dial or disengage the half nuts at any time. You must run the lathe in reverse to return the saddle for the next cut.

[Stustoys]

What Ewan said plus "48,,20 and 24 teeth train to give me 8 TPI"???
Assuming your gearing is the same as mine.

You want
____48 (damn html or whatever taking out my spaces!)
127 120
24
A2 M1

Stuart

[Grahame Collins]

Thanks Ueee

I have just been out to the lathe and my trusty Fuji thread gauge says 3 mm pitch not 8 TPI, like I had thought- Bugger!:(
Stu,

STU ,
I MEANT to type 48,120 and 24 .Bloody finger cant add as well as spell!:doh:

I see 127/120 written several times.The two are 1 PIECE BUT reversible.
And REALISE I do have 127 on the drive train as I reversed them this arvo and forgot about it:?:?

Counting pinion teeth each time,looks like being an ongoing pain in the bum ,so I color coded them and match marked them to the storage case.
Which one to use though?

Grahame

[Stustoys]

My 120/127 isnt reversable.

With a metric leadscrew there should be an indicator table(you cant see the 1's in the picture sorry). Say you want to cut 0.8mm pitch. look up 0.8 on the table. you need the 16 tooth gear and can pick up the thread on 1,3,5,7. 2.8mm pitch you need the 14tooth and can only pick up on 1.
any of the botto[m pitches you can pick up anywhere you like
Stuart

[BRADFORD]

Ever since I got a lathe with reverse I never disengage the half nuts during thread cutting, don't use the thread chaser dial either.
It is a little slower but it is so much easier and removes another potential error.
I find thread cutting quite addictive and I seem to be aways looking to do some job where thread cutting is required.:)

[Grahame Collins]

Thanks lads,

I went back to the lathe and the chart is there not quite under my nose ,but close with the same details as was,on Stu's post with the photo of his table.
The size and placement of the table is a bit different to his,but the data is the same.

My god ! I am turning into a Mr McGoo.

As soon as I have a reasonable thread, I shall post it .
Have a great week end all!
Grahame