Feeling a little restricted.

[Richard.]

Yes, exactly.

Much wiser now cheers.
Yes all my handles have a little back lash before they grab not much mind but it's there.
No slide play at all mind which I guess is more important.

 

[Richard.]

I'm sorry but that is bad advice. "Some" don't say, it is the way it is suppose to be done unless you are using an appropriate full cutting insert tool. The reason for the compound being set to half the thread angle is so that when you advance the tool it is only cutting on the leading edge of the tool. If cutting on both sides you will get increased chatter and a poor cut.

Yes I took that advise from DB vid. I set my tool up so that it was cutting at the leading edge by half the cutting angle.

 

[brightspark]

even a new lathe has backlash

 

[addjunkie]

Make your self some pipe fittings, a good lathe practice excercise. Espescially if you have some factory produced ones to see if they fit together.

 

[MattH]

Much wiser now cheers.
Yes all my handles have a little back lash before they grab not much mind but it's there.
No slide play at all mind which I guess is more important.

Indeed, to compensate for the backlash just wind back past where you need to be then wind up to the required point.

 

[Richard.]

Indeed, to compensate for the backlash just wind back past where you need to be then wind up to the required point.

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.

 

[MattH]

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.

I'll send you a little care package with the book. Don't buy anything yet!

 

[Richard.]

I'll send you a little care package with the book. Don't buy anything yet!

I won't mate. I await your full instruction. In return send me your address as I might have a couple little things you may find useful for your new found skill.

 

[MattH]

I won't mate. I await your full instruction. In return send me your address as I might have a couple little things you may find useful for your new found skill.

Sounds like a plan.

 

[Pete.]

Building on what's already been said, definitely don't use the drive dog when threading, unless it's a single-tooth dog clutch (which it isn't). How you never crossed the threads I don't know. Also using the cross-slide for threading is perfectly acceptable on a sturdy lathe. Using the 30 degree compound method is easier on the machine, the tool and the work especially for the lighter machine.

The best and most fool-proof threading tool I ever saw was made by John Stevenson (though he didn't invent it) - the swing-up threading tool. You can just bang the lathe in reverse without touching the dials and the tool lifts out of the thread just by friction. His machine doesn't even have a compound slide so he uses the cross-slide exclusively. I'll see if I can find a link.

 

[Pete.]

Here you go - http://bbs.homeshopmachinist.net/threads/38585-Swing-threading-tool

More links:

http://mikesworkshop.weebly.com/swing-up-tool-holder.html

http://bbs.homeshopmachinist.net/threads/38585-Swing-threading-tool

 

[Richard.]

Building on what's already been said, definitely don't use the drive dog when threading, unless it's a single-tooth dog clutch (which it isn't). How you never crossed the threads I don't know. Also using the cross-slide for threading is perfectly acceptable on a sturdy lathe. Using the 30 degree compound method is easier on the machine, the tool and the work especially for the lighter machine.

The best and most fool-proof threading tool I ever saw was made by John Stevenson (though he didn't invent it) - the swing-up threading tool. You can just bang the lathe in reverse without touching the dials and the tool lifts out of the thread just by friction. His machine doesn't even have a compound slide so he uses the cross-slide exclusively. I'll see if I can find a link.

The dog clutch is only single tooth well it's a slot and one pin actually but it can only engage in the same place every time. You can't cross thread it like that if the tdi gear doesn't move surely.

 

[Pete.]

You can if it can do more than one rotation without picking up engagement. It might be (probably is) some pitches where you can just stop and start the leadscrew where you want and it will keep time but don't rely on it.

 

[Pete.]

Actually didn't you say that it's a 2mm pitch thread? Is it a 2mm pitch screw?

 

[Richard.]

You can if it can do more than one rotation without picking up engagement. It might be (probably is) some pitches where you can just stop and start the leadscrew where you want and it will keep time but don't rely on it.

I won't. The explanation from Matt made perfect sense now using the tdi. I'm gonna have another crack at it when I've some new sharp tools.

 

[Richard.]

Actually didn't you say that it's a 2mm pitch thread? Is it a 2mm pitch screw?

I'm not sure tbh. The thread was 2.0 but I'll have to measure the lead screw pitch Tomoz. That would make sense though Pete as to why I managed to fluke a usable thread with bad method.

 

[Pete.]

I don't know about your machine but most metric threading lathes need different gears on the threading dial for different pitches of thread.

Example:
http://www.fwhercus.com.au/jrdebay/ebay/Spares/THREAD_DIAL_INDICATOR_CHART.htm

 

[gaz1]

oh for your lathe some info

screwcutting with mandrel handle

 

[Richard.]

I don't know about your machine but most metric threading lathes need different gears on the threading dial for different pitches of thread.

Example:
http://www.fwhercus.com.au/jrdebay/ebay/Spares/THREAD_DIAL_INDICATOR_CHART.htm

That's an interesting read Pete.
I'm unsure as to whether I can change the number of teeth on my thread dial gear as it has 2 gears both sides of the lead screw and they appear to be fixed not adjustable so changing the size of them in my mind would mean they wouldn't physically fit in. Could be wrong mind.

 

[addjunkie]

If you get or down load an instruction book for your machine, all these questions will be answered. I know men dont read instructions, but these details are useful.

On my machine there is 4 different gears on the tdi. From memory. Its a metric machine, on the previous imperial machine there was only one.