Thread cutting

[Mr happy]

Good morning
Wanting to try some imperial screw cutting on metric 140 ) gears on the lathe are 100 80 25
My other gears I have are 120 80 60 50
Advice on what I would need thanks

 

[Tangledfeet]

Better off asking in the relevant forum?

Machining Techniques and Materials

Use this forum to discuss how to use machining equipment.

www.mig-welding.co.uk

 

[Brad93]

Good morning
Wanting to try some imperial screw cutting on metric 140 ) gears on the lathe are 100 80 25
My other gears I have are 120 80 60 50
Advice on what I would need thanks

You'd need a 63T gear as a minimhm

 

[addjunkie]

Once you have the right gear selection, you will need to leave the half nuts engaged as the thread dial indication will not be right on a metric machine for imperial or vice versa

 

[addjunkie]

This may help

Thread 'Imperial Thread Cutting on Metric 140'

Mar 5, 2021

If I have a 127T gear, and a full set of metric changewheels. What other gears do I need to cut imperial threads?

• Brad93
• Replies: 27
• forum: Lathes and other Machining Equipment

 

[Agroshield]

Advice on what I would need thanks

A manual would be a good start:

T. S. Harrison & Sons, Ltd. - Publication Reprints | VintageMachinery.org

 

[RWD3M]

As mentioned above, you need a 127 tooth change gear. They can be quite pricey but an alternative might be a 3d printed gear that woyuld fit onto say a 80T or 100T change gear.

e.g. https://www.thingiverse.com/thing:1808219

 

[dieselsamurai]

As mentioned above, you need a 127 tooth change gear. They can be quite pricey but an alternative might be a 3d printed gear that woyuld fit onto say a 80T or 100T change gear.

e.g. https://www.thingiverse.com/thing:1808219

My lathe has run 3d printed gears for a while now no issues at all

 

[Agroshield]

As mentioned above, you need a 127 tooth change gear.

There are two challenges with that.

First, a 127t gear is quite large, so may not fit in the space available. Hence, unless you know for sure that a Harrison 140 will accommodate a 127t gear, the statement may be problematic.

Second, as stated, the machine is a metric machine cutting imperial threads. That means the 127t gear would be a driver, not, as is usual the other way round, a driven gear, directly on the leadscrew. Being a driver, it has to be higher up in the train, making the physical space challenge above even harder.

The manual linked to above and the thread linked to above would also seem to disagree with your suggestion.

 

[addjunkie]

Above I posted a link to an old thread on the exact subject this was posted by @doubleboost who does a fair bit of this malarkey, with documented evidence of success.

 

[RWD3M]

There are two challenges with that.

First, a 127t gear is quite large, so may not fit in the space available. Hence, unless you know for sure that a Harrison 140 will accommodate a 127t gear, the statement may be problematic.

Second, as stated, the machine is a metric machine cutting imperial threads. That means the 127t gear would be a driver, not, as is usual the other way round, a driven gear, directly on the leadscrew. Being a driver, it has to be higher up in the train, making the physical space challenge above even harder.

The manual linked to above and the thread linked to above would also seem to disagree with your suggestion.

Perhaps your time might be better spent suggesting a solution than dissing others

 

[Kram]

Ride The Gear Train free software by Evan Lewis

This website will tell you how close you can get with your current gears. Often the error can be insignificant. It can also show you where to put them and a rough idea if they fit. A while since I have used it, but once set up, its very good.

 

[Agroshield]

Perhaps your time might be better spent suggesting a solution than dissing others

It was your own choice not to read the original post nor to read two posts above your own giving the correct information.

Is the purpose of this thread to help the OP?

What you read as 'dissing' is actually suggesting a solution by steering the OP away from something that will not work.

 

[Agroshield]

This website will tell you how close you can get with your current gears.

Again, that might be a challenge given the actual machine in question. A Harrison 140 has a gearbox and thus very limited options for gearing between spindle and gearbox input.

The computer program would need to know the exact details of all the ratios in the 140 gearbox in order to perform any meaningful calculations concerning an input train to that gearbox.

I am a simple person. If I want to find something out about a machine, I assume the manufacturer of that machine, via their published instruction manual, probably knows the answer.

 

[Kram]

The website has worked well for my lathe. The website includes details for many common lathes and somone may have already put that informaton in there.

The fact is, manufacturer gear data is often poor as it takes a lot of space, a lot of detail and time, if it were done manually. It is a task that suits a website or application designed for the purpose.

 

[RWD3M]

It was your own choice not to read the original post nor to read two posts above your own giving the correct information.

Is the purpose of this thread to help the OP?

What you read as 'dissing' is actually suggesting a solution by steering the OP away from something that will not work.

I think you're wrong, it seems to work on my L5 and I think the 140 is bigger is it not?

 

[Mr happy]

It was your own choice not to read the original post nor to read two posts above your own giving the correct information.

Is the purpose of this thread to help the OP?

What you read as 'dissing' is actually suggesting a solution by steering the OP away from something that will not wo

It was your own choice not to read the original post nor to read two posts above your own giving the correct information.

Is the purpose of this thread to help the OP?

What you read as 'dissing' is actually suggesting a solution by steering the OP away from something that will not work.

I thought your group was to help newcomers didn’t like your above comment

 

[RichardM]

Have a look on here

Ride The Gear Train free software by Evan Lewis

 

[Mr happy]

Thank you all for your replies

 

[doubleboost]

The 127 will not fit on to a 140 lathe.
I made a 63 not 100% but very close