Coronet Major lathe headstock Insert

[Wood Worker]

I understand that anyone with the Red Coronet Major struggles with headstock fittings as the thread is an obsolete 7/8” 16Tpi.
Having one of these myself and having just started to use the lathe I thought I would source an insert that would allow the use of more modern chucks etc. I did post this on the end of another thread but not sure anyone picked up on it.
I’ve got a price from a local engineers to CNC machine a insert with a 7/8" 16Tpi internal thread and M33 3.5 external thread.
Prices are:-
1 off threaded insert @ 70.00
5 off threaded insert @ 30.00
10 off threaded insert @ 23.00
If anyone is interested please let me know and we could make a bulk purchase and get a good deal .
I’ve added a rough sketch of what I have asked them to price up.
I live in Sale Cheshire and would be willing to post to anyone who would like one.
Cheers SMcK
PS. I hope this doesn’t break any forum rules.

 

[Jarhead1009]

Interested! Having similar issues

 

[Jarhead1009]

I understand that anyone with the Red Coronet Major struggles with headstock fittings as the thread is an obsolete 7/8” 16Tpi.
Having one of these myself and having just started to use the lathe I thought I would source an insert that would allow the use of more modern chucks etc. I did post this on the end of another thread but not sure anyone picked up on it.
I’ve got a price from a local engineers to CNC machine a insert with a 7/8" 16Tpi internal thread and M33 3.5 external thread.
Prices are:-
1 off threaded insert @ 70.00
5 off threaded insert @ 30.00
10 off threaded insert @ 23.00
If anyone is interested please let me know and we could make a bulk purchase and get a good deal .
I’ve added a rough sketch of what I have asked them to price up.
I live in Sale Cheshire and would be willing to post to anyone who would like one.
Cheers SMcK
PS. I hope this doesn’t break any forum rules.

https://www.ebay.co.uk/itm/173945379628

 

[Wood Worker]

Well eventually got my insert made and it turned out I knew the guy at the engineers I had been emailing for prices so got a good deal on that. My insert gave me a M33 3.5 thread so I went looking for a chuck and I found a Record Power SC3 at Elmers hardware for £99 delivered. Its a nice feeling chuck and good value I believe and it all fits on my lathe perfect. Just need to get turning now. Bit cold out in the garage yet.

 

[JKatRedhouse]

I understand that anyone with the Red Coronet Major struggles with headstock fittings as the thread is an obsolete 7/8” ......

Hi, I need a 7/8x16 to 1”x8tpi AND 7/8x16 to M33x3,5mm
I am also in Cheshire near Chester, you found a maker of the M33. Can you advise who made it for you, and ... did you get a bunch of them so i could buy off you?
Any help appreciated JK

 

[Wood Worker]

Hi I did advertise it on the Forum but no one took me up on the offer of getting a few made. Its hard to find anyone with a 7/8" x 16TPI thread tap but the one I found is Brown Engineering in Stockport. He made my insert on his CTC lathe so would have it in its memory to make another I'm sure.
Ive sent contact details on private message

 

[AJH777]

I understand that anyone with the Red Coronet Major struggles with headstock fittings as the thread is an obsolete 7/8” 16Tpi.
Having one of these myself and having just started to use the lathe I thought I would source an insert that would allow the use of more modern chucks etc. I did post this on the end of another thread but not sure anyone picked up on it.
I’ve got a price from a local engineers to CNC machine a insert with a 7/8" 16Tpi internal thread and M33 3.5 external thread.
Prices are:-
1 off threaded insert @ 70.00
5 off threaded insert @ 30.00
10 off threaded insert @ 23.00
If anyone is interested please let me know and we could make a bulk purchase and get a good deal .
I’ve added a rough sketch of what I have asked them to price up.
I live in Sale Cheshire and would be willing to post to anyone who would like one.
Cheers SMcK
PS. I hope this doesn’t break any forum rules.

Hey there,

Trying to figure out why the need to stop 3/8" short of the hex nut?
Clarification would be great.
Could get the old man to machine it but he want's some more info.

Cheers,
Adam H

 

[Democritus]

Hey there,

Trying to figure out why the need to stop 3/8" short of the hex nut?
Clarification would be great.
Could get the old man to machine it but he want's some more info.

Cheers,
Adam H

Hi Adam
This thread is an old one (Sept. 2020).
Best wishes and welcome to our forum.

 

[ChaiLatte]

Trying to figure out why the need to stop 3/8" short of the hex nut?

This is guesswork, so may be incorrect.

As it is an internal thread, the minor diameter of the thread will be smaller than its 7/8" stated dimension.

If the lathe has a plain portion of spindle 7/8" diameter (called a register), something smaller than that will not go over it.

The drawing notes are written in an odd way. A more conventional way would be to note that the left hand 3/8" length of the bore should be 7/8" (plain) diameter, with the remaining length threaded 7/8"-16.

Look at the picture of the Robert Sorby one above. I think the drawing is trying to describe what you see in that picture.