New to me - Colchester Triumph

[Lewis_RX8]

Loose is better than tight, question is does the belt slip on a heavy cut?

Intresting , Heavy cuts before when they where flapping about the cut was all groovy with lines which I thought may be due to the belts moving slightly under high load.

Too loose. Tighten them up.

Cheers pete have little idea what I am looking for on lathe belts so out of interest how could you tell they where too loose is it the vibrations or how the belts were moving

Thanks

 

[Lewis_RX8]

Playing with the threading tool tonight after watching a YouTube video or two , not that nice got a bit of chatter as using cross slide only method so I understand it cuts on both edges and the compound slide method is better so will need to try that to make them nicer

Not making real threads just practise bits really didn't grind the toolpost into the chuck so calling it time well spent getting used to the motions reversing etc

Want to try the rapid threader shame it's only imperial but still good to know

 

[GraemeVW]

In the colchester factory video where they are using the high speed threaded, it looks scary! That thing is flying towards the chuck!

 

[GraemeVW]

When threading, can you set a stop and just let the safety cut feed power when it hit the stop?
Or do you have to be on the ball and cut power feed at the right time?

 

[Lewis_RX8]

In the colchester factory video where they are using the high speed threaded, it looks scary! That thing is flying towards the chuck!

How much do you trust the auto stop

 

[Lewis_RX8]

@GraemeVW

 

[GraemeVW]

Ah, I see.
It has it's own stop.

 

[Screwdriver]

Playing with the threading tool tonight after watching a YouTube video or two , not that nice got a bit of chatter as using cross slide only method so I understand it cuts on both edges and the compound slide method is better so will need to try that to make them nicer

Not making real threads just practise bits really didn't grind the toolpost into the chuck so calling it time well spent getting used to the motions reversing etc

Want to try the rapid threader shame it's only imperial but still good to know

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wow! where are your d.o.c. and speeds at? Those threads look terrible! Is the insert dull or is there an issue with the practice material being too soft/gummy?

It is possible to dive straight in with the cross slide but it Is more of an advanced technique once you have your settings dialled in with a nice sharp insert.

My first foray into thread cutting was just as bad (if not worse) but you are really pushing your luck running into the Chuck that close. Especially for practice purposes, I’d never drive that tight unless I really had to.

 

[Lewis_RX8]

wow! where are your d.o.c. and speeds at? Those threads look terrible! Is the insert dull or is there an issue with the practice material being too soft/gummy?

It is possible to dive straight in with the cross slide but it Is more of an advanced technique once you have your settings dialled in with a nice sharp insert.

My first foray into thread cutting was just as bad (if not worse) but you are really pushing your luck running into the Chuck that close. Especially for practice purposes, I’d never drive that tight unless I really had to.

Agreed lol really crap finish on them , tried with aluminium just scrap bucket grade and seemed to gum up around the cutter like it tears it off rather than cut it. Maybe was pushing it too high DOC can't remember exactly but swarf was coming off thick so would be better doing more cuts at lower DOC?

Good comment on close to chuck that was just how I held the material not on purpose but did not think of it as an issue as was going rather slow since first time but will move it out the chuck more
just in case

Brand new insert branded not cheap Chinese I don't think

What is threading steel like I was thinking alu would be better for learning as softer but maybe not it seems

Cheers

 

[fizzy]

Agreed lol really crap finish on them , tried with aluminium just scrap bucket grade and seemed to gum up around the cutter like it tears it off rather than cut it. Maybe was pushing it too high DOC can't remember exactly but swarf was coming off thick so would be better doing more cuts at lower DOC?

Good comment on close to chuck that was just how I held the material not on purpose but did not think of it as an issue as was going rather slow since first time but will move it out the chuck more
just in case

Brand new insert branded not cheap Chinese I don't think

What is threading steel like I was thinking alu would be better for learning as softer but maybe not it seems

Cheers

Still havent tried threading yet but every video I watch they take very shallow cuts and many passes.

 

[Kram]

Aluminium is generally nice. Avoid mild en3b it tears, Ive done some rough horrible threads in that.

I understand it cuts on both edges and the compound slide method is better so will need to try that to make them nicer

Unless it is a very coarse its not needed.
I have this chart prknted on the wall as a guide, makes a thread much quicker knowing roughtly where to end up. I usually measure before the last pass and then take an extra pass or two.
It says internal but its good enough guide for external assuming you measure to finish.

My lathe has diameter dials so I have scribbled the doubled value and running total down each column.... not needed but preserves some sanity.

 

[Dr.Al]

What is threading steel like I was thinking alu would be better for learning as softer but maybe not it seems

Something like EN1A is really nice to thread. Aluminium's okay (depending on the grade) but you need a very sharp tool. For aluminium you'd probably be better off sharpening a bit of HSS to a 60° angle and using that.

 

[Hood]

Use flood coolant if possible, if not then some cutting oil of some sort.
I never angle the compound, never had the need.
First cut I usually go about 0.5mm on dia then depending on material I may continue at that for the next but usually I drop down to about 0.2mm on dia until finished.

 

[addjunkie]

Use flood coolant if possible, if not then some cutting oil of some sort.
I never angle the compound, never had the need.
First cut I usually go about 0.5mm on dia then depending on material I may continue at that for the next but usually I drop down to about 0.2mm on dia until finished.

Similar here, but I cant afford those new fangled inserts so just grind up hss tool as required.

practice its easy, its usually on the really important bit where you only get one go, I bish it up.

 

[Dr.Al]

Similar here, but I cant afford those new fangled inserts so just grind up hss tool as required.

practice its easy, its usually on the really important bit where you only get one go, I bish it up.

I made a very, very simple jig for grinding HSS threading tools as I'll never get it right if I do it by eye! Hardly took any time to make and makes it trivial to get the included angle right:

Based on an idea by Mike Cox; more details: https://www.cgtk.co.uk/metalwork/grinder/threadingjig

 

[Hood]

One other thing to mention, if you go a bit too deep and get a poor finish do a spring pass or two at the same depth to clean things up before continuing.

 

[Screwdriver]

Agreed lol really crap finish on them , tried with aluminium just scrap bucket grade and seemed to gum up around the cutter like it tears it off rather than cut it. Maybe was pushing it too high DOC can't remember exactly but swarf was coming off thick so would be better doing more cuts at lower DOC?

Good comment on close to chuck that was just how I held the material not on purpose but did not think of it as an issue as was going rather slow since first time but will move it out the chuck more
just in case

Brand new insert branded not cheap Chinese I don't think

What is threading steel like I was thinking alu would be better for learning as softer but maybe not it seems

Cheers

Yes I have been caught out with gummy aluminium. There are so many grades/alloys, a mystery bucket is bound to have some soft, annealed ally in it. I always try to "get away" with using carbide inserts because I have them set up in the lathe but a nice sharp HSS tool is better (same goes for plastic). Steel is neither easier nor harder, it's just different but I always use the compound at 30º (or 29.5º for the pedants) and sneak up on the desired fit.

Finish is not important for practice purposes when all you want to do is find the right pitch and size but it's handy to get an idea how small a cut can take you from bound thread to a sloppy fit! Towards the end you might even only need to make a few spring passes once you're that close.

 

[bletchmonster]

My opinion is of limited worth, but for first attempts I reckon you're doing just fine

 

[Lewis_RX8]

Aluminium is generally nice. Avoid mild en3b it tears, Ive done some rough horrible threads in that.



Unless it is a very coarse its not needed.
I have this chart prknted on the wall as a guide, makes a thread much quicker knowing roughtly where to end up. I usually measure before the last pass and then take an extra pass or two.
It says internal but its good enough guide for external assuming you measure to finish.

View attachment 321462
My lathe has diameter dials so I have scribbled the doubled value and running total down each column.... not needed but preserves some sanity.

Thanks they look handy , how do you measure the thread depth is that just using a bit of wire between the threads then measure with mic and subract off the diameter if you know what I mean

Similar here, but I cant afford those new fangled inserts so just grind up hss tool as required.

practice its easy, its usually on the really important bit where you only get one go, I bish it up.

I made a very, very simple jig for grinding HSS threading tools as I'll never get it right if I do it by eye! Hardly took any time to make and makes it trivial to get the included angle right:

Based on an idea by Mike Cox; more details: https://www.cgtk.co.uk/metalwork/grinder/threadingjig

Good idea and especially for learning I don't want to go chipping all these expensive inserts I got with the lathe just need to set up a little jig like Al's there which looks ideal

My opinion is of limited worth, but for first attempts I reckon you're doing just fine

First time I've cut threads they look like threads and I still have all my fingers so taking that as a win

 

[Munkul]

You should be able to measure thread depth by touching off the tool on the major diameter and zeroing before starting to thread,
It's good enough to get you close before you use something to test fit them anyway...
Nice thing about using compound at 30 degrees is that after you zero on the major dia, its the same measurement as it is on the cross slide (apart from measuring DOC not diameter) so no maths needed. Take it close and then test fit/measure, etc
Apparently you should set it for 29.5 degrees to avoid rubbing altogether.