flexispeed lathe/chuck problem

[jason shawParticipant @jasonshaw24246]

hi, i'm new to all things lathe/threads/internal thread/external thread… I was given an old flexispeed lathe(without thread cutting gear) i know the spindle thread is 1/2-16tpe-bsf..(yay, i understood that much). i was also given 2 chucks, i wandet to mount the second one to maybe try some milling but when i bought a 1/2-16tpi bsf die it doesnt fit the spindle… am i missinf something fundamental here?

[jason shawParticipant @jasonshaw24246]

threads

[Michael GilliganParticipant @michaelgilligan61133]

Is it a split die, Jason ?

[ photos of what you have would probably help ]

If so … you probably need to open it slightly, using the central screw in the [die-stock] holder

Do please check everything carefully, before cutting metal

MichaelG.

[OldironParticipant @oldiron]

Posted by jason shaw on 29/12/2020 15:18:32:

hi, i'm new to all things lathe/threads/internal thread/external thread… I was given an old flexispeed lathe(without thread cutting gear) i know the spindle thread is 1/2-16tpe-bsf..(yay, i understood that much). i was also given 2 chucks, i wandet to mount the second one to maybe try some milling but when i bought a 1/2-16tpi bsf die it doesnt fit the spindle… am i missinf something fundamental here?

 

Sorry I cannot make any sense of this question. If you want to mill in the lathe you will need a milling attachment which usually has a vise attached for work holding. Please explain a little more what you are trying to do.

A good explanation of needs usually helps with a better answer to your enquiry. And why would you need to put a die on the spindle nose if one chuick fits. ?

regards

Edited By Oldiron on 29/12/2020 15:42:24

Edited By Oldiron on 29/12/2020 15:43:15

[old martParticipant @oldmart]

What would you want with a die? You don't want to change the spindle.

[Mike PooleParticipant @mikepoole82104]

I would be careful if you are trying your die on the spindle nose, it can easily take a cut which would not be a good idea. Are you making a seperate dummy spindle to mount one of your lathe chucks? If it is a solid die then you are stuck with the thread it cuts but if it is split then be sure to open it fully for the first cut, then try the chuck if necessary close the die a tiny bit and make another cut. You should arrive at a size where the chuck screws on sweetly. The die stock should be a slightly loose fit on the die. We now have die stocks in metric and imperial sizes which can be confusing, a 25mm die in a 1” stock is a bit loose and a 1” die may well not go in a 25mm stock or be a bit too tight to be fully expanded.

Mike

Edited By Mike Poole on 29/12/2020 16:14:32

[jason shawParticipant @jasonshaw24246]

Thank you all for your help

I'm hoping to answer all … i was wanting to mount the spare chuck on a threaded dummy spindle,

I know that both my chucks fit on the spindle, however, neither of the 1/2'-16tpi bsf dies fit the spindle…

I was thinking I could get a new rod and mess about with some dies and see what's what i suppose, but when i start thinking it gets expensive making mistakes

I have been more than carefull not to start a new thread on the original spindle as this could be much worse for me.

sorry if this could be explained better but my learning really starts from why won't one fit the other…

[SillyOldDufferModerator @sillyoldduffer]

Posted by jason shaw on 29/12/2020 16:40:50:

…I know that both my chucks fit on the spindle, however, neither of the 1/2'-16tpi bsf dies fit the spindle…

sorry if this could be explained better but my learning really starts from why won't one fit the other…

We need a Flexispeed owner or other expert to confirm what the thread actually is.

½" – 16tpi BSF on the spindle sounds reasonable to me but double check, and look for damage. Trust nothing – how sure are you of the dies? (Possibly ½" – 16tpi UN)

A photo of the spindle thread next to a rule would help, also any markings on the dies and where they came from.

Dave

[jason shawParticipant @jasonshaw24246]

hi SillyOD

i'm not sure of anything with the lathe right now, it was given to me a couple of years ago and has sat in a box untill lockdown,

I've had all the spindle and stuff apart to fit a new belt so i'll get it stripped down again and take as many pics as i can of everything, especially any markings that might help.

Jason

[Speedy Builder5Participant @speedybuilder5]

The lathes site says 1/2" BSF so 16tpi is correct for the spindle, but as Jason is new to all this, lets establish a few things. The spindle is the male thread sticking out of the lathe. That IS 1/2" BSF 16tpi. Jason has one chuck that fits. The other chuck doesn't fit and I would think that the thread in the second chuck is damaged, or not the same.

For clarity, a 'die' makes male threaded parts like bolts, and a 'tap' makes female threaded holes like nuts and in this case, the thread on second chuck of Jason's

Jason, do not run the die down the spindle thread unless it is badly damaged. Once it is too small, you will need more than help from this forum to correct it. Have a good look up the thread on your second chuck and see if there is muck in the thread. Perhaps the second chuck has a different thread, and that is your real problem.

[Dave HalfordParticipant @davehalford22513]

Jason,

Where did you buy the die from? Some new ones aren't what they claim to be or won't cut, the same goes for taps.

Have you put a rule against the spindle and checked you get 8 threads in 1/2"

Does the chuck screw on the clockwise?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Speedy Builder5 on 29/12/2020 17:13:34:

The lathes site says 1/2" BSF so 16tpi is correct for the spindle, but as Jason is new to all this, lets establish a few things. The spindle is the male thread sticking out of the lathe. That IS 1/2" BSF 16tpi. Jason has one chuck that fits. The other chuck doesn't fit and I would think that the thread in the second chuck is damaged, or not the same.

[…]

.

Is that really the situation ??

I thought his lathe came with two chucks, and Jason has procured a die with the intention of making a spindle to use the second one for another purpose.

… Checking the die against the lathe spindle, it didn’t fit.

I’m happy to be proved wrong, but if we’re ‘establishing things’ let’s check.

MichaelG.

[jason shawParticipant @jasonshaw24246]

hi speedy, both my chucks fot the spindle(male 1/2'-16 bsf).

I bought a 1/2' -16 tap… that fits both chucks( this i get)

Neither of the 1/2'-16 dies thread onto my spindle, As i said i havent run the die onto the spindle because i know if it screws up the spindle thread i'm going to be in a whole world of hurt with no way to find an answer. ( i could just be being over cautious and maybe i should get a piece of 1/2' bar, cut a thread on it and see if that fits the chucks?)

i get what my teachers meant when the told me YOU WILL USE MATH AFTER YOU LEAVE SCHOOL!

Don't i feel dumb!

Thanks again guys..

Jason

[Neil AParticipant @neila]

I can confirm that a Flexispeed Meteor 2 lathe has a 1/2" x 16 BSF thread on the spindle nose.

You have stated that both of the chucks fit the spindle, so no problem there.

It is just when you try to produce a dummy spindle that you run into trouble, although you have not said if the thread you have cut is too big or too small.

It is possible that the lathe you have is not a Flexispeed but a Simat 101. This lathe is the next version made by Alphabeta Engineering and has a 14mm x 1,5mm thread on the spindle nose.

I would suggest measuring the diameter of the spindle nose thread before trying anything else.

Neil

[SteviegtrParticipant @steviegtr]

He did not say the 2nd chuck did not fit. He just wants to make a spindle to carry it for another purpose.

MG correct.

Steve.

[jason shawParticipant @jasonshaw24246]

sorry guys, i really didn't think to cut into a fresh bar and test fit untill i was reading all the advice and help…

i might have got a bit spooked when the dies didnt fit the spindle… i'll try this before i waste any more of peoples valuable time

Thanks again guys

jason

[Howard LewisParticipant @howardlewis46836]

For those who are puzzled by the idea of putting the Die on the spindle.

It is NOT to cut the spindle, but to use it as a gauge to adjust the Die to the correct size, to finish cut the thread on the stub intended for storing the chuck.

I regularly adjust a Die by setting it on a known thread of that size and type, It saves having an undersize thread, or having to recut the to reduce to it the correct size.

If you can find a 1/2 BSF bolt try the Die on it.

For the pedants, I am not talking in terms of making micrometers, but of holding things together with nuts and bolts.

If the Die is already too small to fit on the spindle, the thread cut on the storage stub with it would be undersize, so that the chuck would be a loose fit on it.

Sounds like time to check that the spindle nose IS 1/2 BSF (16 tpi ) and that the Die really IS 1/2 x 16 tpi (If either were 1/2 UNF the thread would be 20 tpi, or if 1/2 BSW (12 tpi ). The difference in thread pitches between the parts should immediately be visible with barely need to double check with thread gauges.

Although that might be a good ides here, to confirm the facts..

Alternative ideas.

Get a 1/2 BSF bolt / stud, fix this to a base, and screw the chuck onto it. Even simpler, turn a piece of bar or broom handle to just under the core diameter (0.420" ) and just hang the chuck on there.

If the storage is on a wall, set the stub at an angle so that the chuck slides towards the wall rather than being horizontal.

Let us know how you get on

Howard

[BazyleParticipant @bazyle]

Check that the die is BSF and not UNF.

[jason shawParticipant @jasonshaw24246]

Hi Howard,

thank you for your time, you understood why i was trying the dies against the spindle, as soon as i'm back to the shop i'll cut a test thread on a fresh bar but i'll also strip the lathe down and try to get some real close up detail pictures,

In the meantime i have ordered a set of bsf thread gauges, whichever happens first will give me a better picture of what's happening here. Needless to say, both chucks, and the backplate all fit onto the tap that i bought as per the Flexispeed data says (Lathes.co.uk..Thank you), and also all three fit the spindle on the lathe, so it would seem that it's the dies that are the problem.

after reading all of these replies, and a few of the other flexispeed threads on the net i'm realising i have not only a steep learning curve but a fun and intersting one too.

Thanks again guys

Jason

[jason shawParticipant @jasonshaw24246]

Hi Bazyle

I saw somebody mentioned that earlier in the thread so i looked into it and found that there are 2. 1/2" -16 tpi, one bsf and one unf. i almost ordered a unf die just to check, somebody said some die markings on newer taps and dies can be wrong.

I have a lot to learn my friend… If it's something i can get my teath into i'll think about going the whole hog and upgrading to a lathe with thread cutting and start learning all over again.. time will tell.

Thanks for your time

Jason

[BazyleParticipant @bazyle]

You said the dies don't fit the spindle. If they are split dies they won't just on their own. You would need a sedie holder with 3 screws. The middle screw fits into the split and forces the die open a bit.
If it is not a split die it is really only good for cleaning up a damaged thread on an old bolt.

If the tap fits the chuck easily it is undersize so a nut made with it might not fit on the spindle. However the tap may have a taper and you may only be using the end of it that will be a bit small.

Another area that gets difficult with home made threads is the roots and crests. Your nut thread might be the right pitch and inside diameter and look good but the depth of the thread not enough or the depth good but the inside diameter still too small.
The nose thread might be described as 1/2 BSF but might not be made to the actual spec with rounding of the peaks and troughs. Although a regular bolt has been suggested as a test piece they are often made a loose fit unless part of a special precison machine.

[Howard LewisParticipant @howardlewis46836]

1/2 UNF is 20 tpi. Finer than 16 tpi

1/2 UNC is 13 tpi, Coarser than 16 tpi

AND both are a 60 degree thread form, not the 55 degree of the BSF and BSW.

so 1/2 BSF being 16 tpi is in between.

STUPID question

The Die isn't 7/16 BSF is it? That would not fit on the spindle. You said that it wouldn't fit the 1/2 BSF Tap.

Core daimeters 1/2 BSF is 0.4200,, 7/16 BSF core dia. is 0.3665. Might be worth checking the die with a bit of bar turned down to those sizes.

Howard

[jason shawParticipant @jasonshaw24246]

Hi baz,

the first die i got was a 1 inch closed round, and i then got a 2 inch split die, and a week later got a holder/tool for it, so that's taken care of.

Again i was carefull not to start a new thread when testing and all fit back together as normal afterwards so that's all good, having said all this, I'm sure it'll get to the bottom of the "great flexispeed thread mystery( a lot of time on my hands due to lockdown)

The first thing i ever turned in my life was a mahogany table lamp, on a HUGE metal lathe in primary boarding school, 9 or 10 YRS old if i remember rightly (47 now) , (before the health and safety bods got involved).

The second thing I'll turn in my life will probably be a metal pen on this really quite pretty little flexispeed,

I really am starting at the bottom, so again guys, thank you all so much for all your timer,help and advice.

Jason

[jason shawParticipant @jasonshaw24246]

Howard, this demonstrates my last messege (starting form the bottom), I even read a chart wrong… i have a lot to learn, but thank you.

Jason

[Howard LewisParticipant @howardlewis46836]

Jason, You won't be the first, or the last, to misread a chart, or set up a machine wrongly.

The man who never made a mistake, never made anything.

The main thing is to learn from our mistakes.

"Experience is what allows you to recognise the mistake the next time that you make it"

At some time, we have all set the spindle turning in reverse, or inadvertently cut a REAL odd ball thread and then wondered why it won't fit! (My last one was 0.964 mm pitch, or 26.4 tpi; ALMOST 1 mm pitch, but out by a factor of 120/127 )

If you can get some sets of thread gauges, Whit, Metric and Unified. At various times they will allow you to recognise a thread, by its form, or pitch. But you will come across some "specials" Myford 1.125" x 12 tpi Whit form, 2.250" x 8 tpi Whit form on my lathe Filters for cameras are often 0.75 mm pitch although the sizes may differ, for instance.

It may be extra expense, but assuredly "will come in handy one day"

Howard

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