New to me - Colchester Triumph

[m_c]

I find if i am turning a bar of "draggy" steel that's giving feed lines i just max the chuck speed out and go really fine on the cut with sharp HSS...really helps things out.

I was getting lines like that on my much weedier lathe. Tried HSS with a fat radius and managed better. Stay away from pointy carbide.

12mm diameter.

In softer steels, suitably ground/sharpened HSS does typically give a better finish, especially with small cuts.

Carbide inserts for steel essentially tear/rip metal away, as they are not a sharp insert. Blunt carbide inserts rely on a good depth of cut to ensure the blunt edge isn't just rubbing on the surface.
HSS on the other hand needs to be sharp, but the downside is it's not as durable. You can take big cuts with HSS, but the cutting edge will wear/blunt relatively quickly. The benefit of the sharp edge, is you can get away with taking small cuts, where a carbide insert would just be trying to rub the surface.

If you want sharp edged carbide inserts, you can use aluminium inserts for finishing cuts. But due to the inherent brittleness of carbide and the sharp edge, they don't withstand much abuse.

 

[Hood]

I was getting lines like that on my much weedier lathe. Tried HSS with a fat radius and managed better. Stay away from pointy carbide.

12mm diameter.

Just to clarify, my pictures were of a roughing feedrate of 0.3mm/rev. It was done specifically to show the difference in appearance between different materials.

 

[prepman]

Mild steel will mar and rip as it cuts, higher alloy steels will cut better with less ripping. Aluminium and stainless are more ductile so tend to leave a really nice finish as they sort of smear.

The problem with going too low on the feedrate is you will get long stringy swarf which will mar the surface of the material you have just cut.

Also big difference between hot and cold rolled.

 

[prepman]

That's the plan at the moment seems cheapest and easiest way to get it sorted so should be fine

I ripped out the old switchgear out and put the VFD in there. The motor had been repaired, the ends of the windings had been jointed internally, making it permanent star, which was no good for 240. So I had to separate and extend to a new terminal block to make it delta. I am certain that the vfd should never be disconnected from the motor, but switched on the supply side. For belt & braces isolation I unplug it (13A).

Wish I'd selected a different gear when I made the video. The second selector brings in the noisy one. I had to drill through power switch shaft as didn't have a reverse lever or switch. Which I had to design and make. Yours has. Have you got a taper turning attachment?

 

[Kram]

Also big difference between hot and cold rolled.

Interesting, just for mild or all steels? Im aware that cold will move as the stresses change but no idea if it cuts better or worse.
I dont plan on buying any more mild, used most of it up. There are much better steels at a similar price.

 

[Lewis_RX8]

Well managing to get some progress , made sure all the gibs where nipped up , I just fully locked the compound slide as recommended by hood before as was not using it so try and take play out of the equation. I also ran it at a speed far away from the resonance to try and cut down on the vibrations. New tooltip because I was too ham-fisted with the tool post and smacked the insert into tailstock but never mind new cutting point on insert took any dullness out the equation.



1200RPM , 5 Thou per rev feed and 0.8 DOC on a 04 radius TNMG from kennemetal.

Now I say it the photo shows up the feed marks more so than by eye but they are a lot less apparent than they where before and can just be picked up by fingernail where as before it was like rubbing your nail on a file as the grooves where deeper.

Now the next part with turning like this taking heavy DOC working out how the spring in the part works as I see if you go in say 0.5mm DOC then go backwards it cuts more so I assume this is the spring somewhere and makes it more difficult to get to a final measurement compared to light cuts.

And here is how bad the lines where before

Then with the lowest feed at 1200RPM using the ultra sharp ally inserts it gave a nice finish which seems to be alot more uniform than what I have been getting previously not a mirror but a very very smooth finish with uniform lines and reflections so happy with that. Will be very handy if holding tight tolerences as can shave off a few thou per cut happily and leave a good finish.

Also had a go with the proper technique I hope for checking the spindle bearings , Seems about 0.02mm of play up and down with force on a pry bar pushing up. Will need to remember to try when it is warm

Unfortnatley not sure what exact measurement I am looking for here as do not think it was published by colchester in the manual but it seems reasonable to me.

Now doing this I was using the tailstock a little aswell and forgot that I had aligned the headstock so will need to align the tailstock now as it would not sit right inparts and was being pulled , The manual calls for a ground test bar which I dont have so thinking of using the simmilar method to headstock alignment turning a test bar and using mics on it untill all taper is removed then I know it is running true and not pulling the part to either side.

Photo didnt really work but by eye it was clearly not aligned

Again thanks for the help everyone , Still got a few things to try with HSS and other suggestions

 

[Pete.]

Nothing wrong with those finishes. Get some emery paper and they will look as shiny as everyone else who has some.

I'd leave the spindle well alone going by your dial gauge reading. Just get on with doing some turning.

As for your spring under heavy cuts it's something you're going to have to get used to. Get some scrap, pick a target diameter and see how close you can get to hitting it by taking same-size cuts and measuring each time.

For instance, say you have a piece of 2" and a target of 1.5" to hit.

Take a 50 thou cut and measure, say you get 1.910"
Take a 55 thou cut and measure, say you get 1.803"
Take a 52 thou cut and measure, say you get 1.699"
Take a 49 thou cut - say you get 1.600"
Your last cut of 50 thou should hit 1.500"

It doesn't have to be 50 thou you can use any size cut the main thing is that you get to a point where the amount on the dial equals the amount coming off and keep that cut depth all the way to the finish. You can adjust up and down a bit say 5% without a penalty.

If you try to sneak up on a size by doing what many do and keep halving the cut depth you: 1. lose your finish 2. take forever and 3. keep halving your spring forces until you over-shoot and end up small. You can do it with super-sharp tools and there's many ways to skin a cat but the above is what I do.

 

[prepman]

Interesting, just for mild or all steels? Im aware that cold will move as the stresses change but no idea if it cuts better or worse.
I dont plan on buying any more mild, used most of it up. There are much better steels at a similar price.

It isn't uniform hardness. Can be anything, not nice but cheap.

 

[Sean64]

Well managing to get some progress , made sure all the gibs where nipped up , I just fully locked the compound slide as recommended by hood before as was not using it so try and take play out of the equation. I also ran it at a speed far away from the resonance to try and cut down on the vibrations. New tooltip because I was too ham-fisted with the tool post and smacked the insert into tailstock but never mind new cutting point on insert took any dullness out the equation.



1200RPM , 5 Thou per rev feed and 0.8 DOC on a 04 radius TNMG from kennemetal.

Now I say it the photo shows up the feed marks more so than by eye but they are a lot less apparent than they where before and can just be picked up by fingernail where as before it was like rubbing your nail on a file as the grooves where deeper.

Now the next part with turning like this taking heavy DOC working out how the spring in the part works as I see if you go in say 0.5mm DOC then go backwards it cuts more so I assume this is the spring somewhere and makes it more difficult to get to a final measurement compared to light cuts.

View attachment 326026

And here is how bad the lines where before

Then with the lowest feed at 1200RPM using the ultra sharp ally inserts it gave a nice finish which seems to be alot more uniform than what I have been getting previously not a mirror but a very very smooth finish with uniform lines and reflections so happy with that. Will be very handy if holding tight tolerences as can shave off a few thou per cut happily and leave a good finish.


View attachment 326024

Also had a go with the proper technique I hope for checking the spindle bearings , Seems about 0.02mm of play up and down with force on a pry bar pushing up. Will need to remember to try when it is warm

Unfortnatley not sure what exact measurement I am looking for here as do not think it was published by colchester in the manual but it seems reasonable to me.

Now doing this I was using the tailstock a little aswell and forgot that I had aligned the headstock so will need to align the tailstock now as it would not sit right inparts and was being pulled , The manual calls for a ground test bar which I dont have so thinking of using the simmilar method to headstock alignment turning a test bar and using mics on it untill all taper is removed then I know it is running true and not pulling the part to either side.

Photo didnt really work but by eye it was clearly not aligned

View attachment 326027

Again thanks for the help everyone , Still got a few things to try with HSS and other suggestions

Get your tailstock aligned and use it ,you'll be surprised the difference it will make . And as Pete has said get to know your machine .

 

[minimutly]

When I was making taper pins the other day I found the piece of steel from some scrap electrical equipment cut really well, like it had lead in it. And when I ground the end in the grinder it smelt like galv.
Made good taper pins though.
And a while ago when I made a new front axle for my trike out of an old metro driveshaft I found the chip shape changed allong the shaft.
The joys of using scrap steel...

 

[prepman]

Well managing to get some progress , made sure all the gibs where nipped up , I just fully locked the compound slide as recommended by hood before as was not using it so try and take play out of the equation. I also ran it at a speed far away from the resonance to try and cut down on the vibrations. New tooltip because I was too ham-fisted with the tool post and smacked the insert into tailstock but never mind new cutting point on insert took any dullness out the equation.



1200RPM , 5 Thou per rev feed and 0.8 DOC on a 04 radius TNMG from kennemetal.

Now I say it the photo shows up the feed marks more so than by eye but they are a lot less apparent than they where before and can just be picked up by fingernail where as before it was like rubbing your nail on a file as the grooves where deeper.

Now the next part with turning like this taking heavy DOC working out how the spring in the part works as I see if you go in say 0.5mm DOC then go backwards it cuts more so I assume this is the spring somewhere and makes it more difficult to get to a final measurement compared to light cuts.

View attachment 326026

And here is how bad the lines where before

Then with the lowest feed at 1200RPM using the ultra sharp ally inserts it gave a nice finish which seems to be alot more uniform than what I have been getting previously not a mirror but a very very smooth finish with uniform lines and reflections so happy with that. Will be very handy if holding tight tolerences as can shave off a few thou per cut happily and leave a good finish.


View attachment 326024

Also had a go with the proper technique I hope for checking the spindle bearings , Seems about 0.02mm of play up and down with force on a pry bar pushing up. Will need to remember to try when it is warm

Unfortnatley not sure what exact measurement I am looking for here as do not think it was published by colchester in the manual but it seems reasonable to me.

Now doing this I was using the tailstock a little aswell and forgot that I had aligned the headstock so will need to align the tailstock now as it would not sit right inparts and was being pulled , The manual calls for a ground test bar which I dont have so thinking of using the simmilar method to headstock alignment turning a test bar and using mics on it untill all taper is removed then I know it is running true and not pulling the part to either side.

Photo didnt really work but by eye it was clearly not aligned

View attachment 326027

Again thanks for the help everyone , Still got a few things to try with HSS and other suggestions

Bit the bullet and took up preload. There was movement in the bearing. Increased tension using copper
drift, so has everybody else in the past looking at the castellation

No visible sign of deflection using the bar and finally was able to finish off a disastrous parting operation.
Downside is I'm back to an unacceptable taper. I'll slacken the headstock off tomorrow and bed it in. Hopefully that'll do it. Otherwise it's shim-shimmeny, shim shim sheree....
Also need to lower the ball bearing clutch tension, to protect from feed lock up.

 

[prepman]

Well managing to get some progress , made sure all the gibs where nipped up , I just fully locked the compound slide as recommended by hood before as was not using it so try and take play out of the equation. I also ran it at a speed far away from the resonance to try and cut down on the vibrations. New tooltip because I was too ham-fisted with the tool post and smacked the insert into tailstock but never mind new cutting point on insert took any dullness out the equation.



1200RPM , 5 Thou per rev feed and 0.8 DOC on a 04 radius TNMG from kennemetal.

Now I say it the photo shows up the feed marks more so than by eye but they are a lot less apparent than they where before and can just be picked up by fingernail where as before it was like rubbing your nail on a file as the grooves where deeper.

Now the next part with turning like this taking heavy DOC working out how the spring in the part works as I see if you go in say 0.5mm DOC then go backwards it cuts more so I assume this is the spring somewhere and makes it more difficult to get to a final measurement compared to light cuts.

View attachment 326026

And here is how bad the lines where before

Then with the lowest feed at 1200RPM using the ultra sharp ally inserts it gave a nice finish which seems to be alot more uniform than what I have been getting previously not a mirror but a very very smooth finish with uniform lines and reflections so happy with that. Will be very handy if holding tight tolerences as can shave off a few thou per cut happily and leave a good finish.


View attachment 326024

Also had a go with the proper technique I hope for checking the spindle bearings , Seems about 0.02mm of play up and down with force on a pry bar pushing up. Will need to remember to try when it is warm

Unfortnatley not sure what exact measurement I am looking for here as do not think it was published by colchester in the manual but it seems reasonable to me.

Now doing this I was using the tailstock a little aswell and forgot that I had aligned the headstock so will need to align the tailstock now as it would not sit right inparts and was being pulled , The manual calls for a ground test bar which I dont have so thinking of using the simmilar method to headstock alignment turning a test bar and using mics on it untill all taper is removed then I know it is running true and not pulling the part to either side.

Photo didnt really work but by eye it was clearly not aligned

View attachment 326027

Again thanks for the help everyone , Still got a few things to try with HSS and other suggestions

Long shot....but it might be worth checking change gears. Just to make absolutely sure that the feedrates are what you think they are.

 

[Kram]

Then with the lowest feed at 1200RPM using the ultra sharp ally inserts it gave a nice finish which seems to be alot more uniform than what I have been getting previously not a mirror but a very very smooth finish with uniform lines and reflections so happy with that. Will be very handy if holding tight tolerences as can shave off a few thou per cut happily and leave a good finish.

Dont waste those on steel, they have too much top rake.
The inserts I use will take off 0.01mm from dia, or upto a 1mm DOC quite happily and give reasonable life with a good finish.

The negative dnmg's you were trying to use suit deeper cuts. For light finishing cuts a small positive insert is better. Insert should suit what your trying to do not the size of lathe.

 

[Lewis_RX8]

Nothing wrong with those finishes. Get some emery paper and they will look as shiny as everyone else who has some.

I'd leave the spindle well alone going by your dial gauge reading. Just get on with doing some turning.

As for your spring under heavy cuts it's something you're going to have to get used to. Get some scrap, pick a target diameter and see how close you can get to hitting it by taking same-size cuts and measuring each time.

For instance, say you have a piece of 2" and a target of 1.5" to hit.

Take a 50 thou cut and measure, say you get 1.910"
Take a 55 thou cut and measure, say you get 1.803"
Take a 52 thou cut and measure, say you get 1.699"
Take a 49 thou cut - say you get 1.600"
Your last cut of 50 thou should hit 1.500"

It doesn't have to be 50 thou you can use any size cut the main thing is that you get to a point where the amount on the dial equals the amount coming off and keep that cut depth all the way to the finish. You can adjust up and down a bit say 5% without a penalty.

If you try to sneak up on a size by doing what many do and keep halving the cut depth you: 1. lose your finish 2. take forever and 3. keep halving your spring forces until you over-shoot and end up small. You can do it with super-sharp tools and there's many ways to skin a cat but the above is what I do.

Yea more than happy with them now , aye its not been touched for the past 20 years and seems to happy where it is so will not messing about with it.

Thanks for the explanation and I see what you mean to be able to work factoring spring in the dimensions rather than working against it every cut.

Get your tailstock aligned and use it ,you'll be surprised the difference it will make . And as Pete has said get to know your machine .

Thats the plan.

Bit the bullet and took up preload. There was movement in the bearing. Increased tension using copper
drift, so has everybody else in the past looking at the castellationView attachment 326077View attachment 326076View attachment 326078View attachment 326075

No visible sign of deflection using the bar and finally was able to finish off a disastrous parting operation.
Downside is I'm back to an unacceptable taper. I'll slacken the headstock off tomorrow and bed it in. Hopefully that'll do it. Otherwise it's shim-shimmeny, shim shim sheree....
Also need to lower the ball bearing clutch tension, to protect from feed lock up.

Nice one , What sort of play did you have before adding more preload out of interest ?. I have also heard a rule of thumb if a lathe can part off 2" steel bar its half decent lol. I spent a while adjusting my headstock.

Dont waste those on steel, they have too much top rake.
The inserts I use will take off 0.01mm from dia, or upto a 1mm DOC quite happily and give reasonable life with a good finish.

The negative dnmg's you were trying to use suit deeper cuts. For light finishing cuts a small positive insert is better. Insert should suit what your trying to do not the size of lathe.

Have a few positive inserts all with massive radius IIRC but will have a look at some that fit on my tool holders.

 

[Sean64]

When I was making taper pins the other day I found the piece of steel from some scrap electrical equipment cut really well, like it had lead in it. And when I ground the end in the grinder it smelt like galv.
Made good taper pins though.
And a while ago when I made a new front axle for my trike out of an old metro driveshaft I found the chip shape changed allong the shaft.
The joys of using scrap steel...

You did well turning a driveshaft ,normally they are hard as a .......

 

[addjunkie]

And a while ago when I made a new front axle for my trike out of an old metro driveshaft I found the chip shape changed allong the shaft.
The joys of using scrap steel...

Every drive shaft / half shaft I have cut and or machined has been hard as hell on the outside and softish inside.

For an axle for a trike front end, you probably want to be using EN16T or 8 as a minimum. The forces through a trike front end are quite different to a bike front end.

 

[minimutly]

Every drive shaft / half shaft I have cut and or machined has been hard as hell on the outside and softish inside.

For an axle for a trike front end, you probably want to be using EN16T or 8 as a minimum. The forces through a trike front end are quite different to a bike front end.

Harry enfield voice "you dont want to be doing thaat"
Thanks, it was to replace a tubular axle with a bolt welded to it, which had been machined and had cracked.
I was happy with a driveshaft. Metro ones aren't that hard.

 

[prepman]

Yea more than happy with them now , aye its not been touched for the past 20 years and seems to happy where it is so will not messing about with it.

Thanks for the explanation and I see what you mean to be able to work factoring spring in the dimensions rather than working against it every cut.



Thats the plan.



Nice one , What sort of play did you have before adding more preload out of interest ?. I have also heard a rule of thumb if a lathe can part off 2" steel bar its half decent lol. I spent a while adjusting my headstock.



Have a few positive inserts all with massive radius IIRC but will have a look at some that fit on my tool holders.

Didn't dial before adjustment as I could hear it. With preloaded bearings there shouldn't be any IMHO. The lathe headstock had thick oil in it when I got it. Probably 20/40 or some such. The feed gearbox would have needed a forensic analysis. Horrible. There's video or my channel. Charlie Chan

 

[prepman]

Well managing to get some progress , made sure all the gibs where nipped up , I just fully locked the compound slide as recommended by hood before as was not using it so try and take play out of the equation. I also ran it at a speed far away from the resonance to try and cut down on the vibrations. New tooltip because I was too ham-fisted with the tool post and smacked the insert into tailstock but never mind new cutting point on insert took any dullness out the equation.



1200RPM , 5 Thou per rev feed and 0.8 DOC on a 04 radius TNMG from kennemetal.

Now I say it the photo shows up the feed marks more so than by eye but they are a lot less apparent than they where before and can just be picked up by fingernail where as before it was like rubbing your nail on a file as the grooves where deeper.

Now the next part with turning like this taking heavy DOC working out how the spring in the part works as I see if you go in say 0.5mm DOC then go backwards it cuts more so I assume this is the spring somewhere and makes it more difficult to get to a final measurement compared to light cuts.

View attachment 326026

And here is how bad the lines where before

Then with the lowest feed at 1200RPM using the ultra sharp ally inserts it gave a nice finish which seems to be alot more uniform than what I have been getting previously not a mirror but a very very smooth finish with uniform lines and reflections so happy with that. Will be very handy if holding tight tolerences as can shave off a few thou per cut happily and leave a good finish.


View attachment 326024

Also had a go with the proper technique I hope for checking the spindle bearings , Seems about 0.02mm of play up and down with force on a pry bar pushing up. Will need to remember to try when it is warm

Unfortnatley not sure what exact measurement I am looking for here as do not think it was published by colchester in the manual but it seems reasonable to me.

Now doing this I was using the tailstock a little aswell and forgot that I had aligned the headstock so will need to align the tailstock now as it would not sit right inparts and was being pulled , The manual calls for a ground test bar which I dont have so thinking of using the simmilar method to headstock alignment turning a test bar and using mics on it untill all taper is removed then I know it is running true and not pulling the part to either side.

Photo didnt really work but by eye it was clearly not aligned

View attachment 326027

Again thanks for the help everyone , Still got a few things to try with HSS and other suggestions

My range of tooling for Student, I need to make some more holders in the shaper. The oddball one is an acme HSS I used to make the cross-slide feed screw. The circular one gives a smooth final finish, IF it doesn't chatter

 

[prepman]

I had found that after all the adjustments I've done over the years, there is one that I never considered (silly me). The saddle front strip 8594/8597. There is lift (a lot) in the front edge, but no adjustable gib strip. The problem isn't insurmountable, but intrguing. Obviously shimming wouldn't work unless it was the removal of.
No signs in parts diagram that there are any? I can mill a new strip, but someone must know the answer. No guesses please The carriage can be clamped to eliminate it during crossfeeding. But not the answer?