Sincere Lathe Threading Compatibility with the Cowells 90CW

[dralexmv]

I would like to understand if the threading for the accesories made for the Sincere lathe (faceplates, chucks, collets, etc) are compatible with the Cowells 90CW lathe. 

My use case is the fabrication of bridges for existing movements that can be engraved / finished by myself. I would like to start with the cheaper Sincere lathe and accessories, and then upgrade the lathe to the 90CW while keeping all the Sincere accessories. 

Outside of the actual operation of the lathe, I am quite a novice in the intricacies of accessory threading. I would also like a recommendation (book, online resource, etc) on how to adequaltely assess the compatability between the accessories of two distinct lathes.

[oldhippy]

I suggest you contact both makers and put all your questions to them. Lathe accessories can be a minefield, you will find some you might even be able to adapt yourself. I suggest you shop around and don’t forget you might want to undertake different tasks as you improve. The more you learn the more you will want to do.  Accessories can be very expensive so you might need deep pockets. If you buy second hand be very careful.   

Edited April 26, 2018 by oldhippy

[jdm]

3 hours ago, oldhippy said:

I suggest you contact both makers and put all your questions to them. 

It's virtually impossible to contact the actual Chinese makers of Sincere lathes. And the re-sellers on Ebay may or may not posses the technical details. Always lots of misunderstandings when communicating with Chinese.

However it's know that the machine is perfectly good for both beginners and advance users.

[measuretwice]

what is the TIR of a typical Chinese spindle/collet combo vs a German, Swiss or American set up?  Anyone measured? 

Experience has conditioned me to expect much lower quality from the low cost Chinese tools and tooling, but I have not tried one of the lathes so a negative comment from me would just be extrapolation, although not devoid of rational...there are reasons for it.  I would be curious to know what something quantifiable like spindle TIR and the Max TIR over a set of collets actually is vs manufacturers claims and our prejudices.

OP, can't help on your question......the obvious idea is to check the manufactures specs for the spindle, but that might be easier said than done

Edited April 26, 2018 by measuretwice

[rodabod]

Well, the Chinese ER collets are quite good in my experience (I use them alongside Conflex 8mm collets). Some Chinese stuff is ok. 

[jdm]

Thread unlocked on member's request.

Please stay on topic; postings which do not will be removed.

[maclerche]

Thanks jdm!

Hi Dralecmv

I myself own a Cowell's 90CW (just got it) and have done some research before my purchase.

A Cowell's 90CW has a spindle nose that fits 8mm. watchmaker types B8 (European Schaublin) and WW (American Webster Whitcombe), all this fit in Cowell's spindle. The difference is as you mention the thread.
B8 has a thread called 6.82mm x 0.625mm pitch with 55 degree threads.
WW collets have 0.275 "x 40TPI or 6.985mm x 0.635mm pitch.
The Chinese Sincere uses M7x0.75 on their accessories.

However, this is not a major problem. Sincerely can provide a universal drawbar that can be used for your Cowells when that day comes. Someone also feels great pleasure by producing some of their tools. Therefore you can easily find tap and die and make it yourself.

Cowells 90CW comes as standard with Drawbar for B8 collets. But as the machines are built to order it will be easy to get it delivered with just the drawbar you want. Even my goal is to make lots of drawbars so I can use what I want.

I can not recommend that you buy Sincere collets, as their runout is way too big for watchmaking!

"Dear Valued Customer, these collets run out is 0.02mm,"  

If you want to meet small run out for small money i think Sherline is the way ..(however, they are not hardened)

If you want to read more about this, Jere Mihalov has written everything about Cowell's 90CW and much about collets treads and other equipment.

https://watchmaking.weebly.com/other-lathe-attachments.html

 

 

 

[maclerche]

Ohh i forgot.. 

I actually intended to buy a Sincere face plate. as it seems to be the right choice for a Cowell's 90CW as well. Dean DK shows it so well here >>>  

 

[Tudor]

Making bridges is above my pay grade but if I was doing it, I’d probably want to use a boring head, rather than a lathe. 

Location and perpendicularly seem critical to me, as a novice. You can drill, team, and then tap without moving the location of the hole center. 

My experience with larger tapped holes I use the Bridgeport (knee mill) and lock the cross slide once I have my location. Spot drill, drill, tap without changing location. If it’s critical I’ll run my drill but in a collet rather than a chuck. I can also under-drill and ream it to size prior to tapping. This is also good for counter-boring where an endmill might be used for the counter and you end up with uniform space all around the screw head.