• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

BB CX701 lathe spindle nominal measures?

PaulL

PaulL

Technologist at Large
Premium Member
My lathe is a Busy Bee/Craftex CX701. I'm trying to figure out my nominal spindle dimensions: nose, bolt pattern.
The spindle flange is 125mm. The nose is 70mm (2 3/4")across, with a 43.5mm (1.7") passthrough.
I've measured across the studs on a chuck, subtracted the diameter of one stud to get 84.4mm, and divided by sqrt(3) to get a nominal radius of 49mm (+- 0.5 on a lack of measurement repeatability), giving a bolt hole radius of 98mm, or 3.86", effectively.
I've been looking at tables of spindles, including, for instance, that at https://www.northlandtool.com/spindle-nose-standards/ .
Since there are no bolt holes in the nose itself, I expect it to be a B2 class spindle nose, but there is *nothing* I can see with anywhere near that bolt-hole radius.
Any idea where else to look up my nominal specifications? The manual is, of course, no help.
I'd love to know my nominal nose taper, for example, before machining a back plate to fit it. The landing is so short (7.14mm) that it's difficult to get a confident angle off it even with a DTI in the compound.
 
@PaulL This is the drawing I received.
I've asked for a closer shot of the cut off side of the page.
 

Attachments

  • 290 SPINDLE.jpg
    290 SPINDLE.jpg
    149.6 KB · Views: 43
Last edited:
David_R8 said:
@PaulL This is the drawing I received.
I've asked for a closer shot of the cut off side of the page.
Click to expand...
That is gloriously helpful! Just missing the nose angle in the cut off side.
No ISO-702 spindle has a 98mm bolt circle :-)
Paul
 
The real question, of course, is how we can get our hands on these drawings in a more "regular" way. Critical components should be drawn like this in the manual!
 
jcdammeyer said:
Wow! You got the 98mm bolt circle correct. I'm guessing the #5 means it's an MT 5 taper. If I were to eyeball the bevel at the nose I'd guess a 45 degree chamfer.
Click to expand...
The chamfer is easy, but I expect some angle on the nose, given that my chucks slip on wobbly and get tighter as I press them home. But it won't be much.

Though I don't see anything on the drawing. So... back into the shop for a minute.
 
It's also possible your chucks have a slight taper. From the drawing it doesn't look like the end of the spindle does. Perhaps turn a piece of scrap with that ID from the drawing and see if it slips on. Tedious I know but might give you a clue.
 
PaulL said:
Though I don't see anything on the drawing. So... back into the shop for a minute.
Click to expand...
Oh, there is no taper. At all. Just the chamfer. I wonder how much that limits repeatability of chuck mounting? Only a problem for the 3-jaw, I guess.
 
jcdammeyer said:
My guess is they've added a taper, very slight, to the inside bore of the chucks and face plate. So it becomes almost a press fit and that's how it's centered.
Click to expand...
Yes, I can make out a tiny difference in light reflection in the chucks and backplates. It also explains the slight worn spots on the spindle nose, which appears to be gaining a matching taper ;-)
 
PaulL said:
Yes, I can make out a tiny difference in light reflection in the chucks and backplates. It also explains the slight worn spots on the spindle nose, which appears to be gaining a matching taper ;-)
Click to expand...
Get some lapping compound and call it a day :p
 
I really feel like it's time to make a camlock adapter for this thing.
Not that I trust my precision particularly at this point...
 
You must log in or register to reply here.
Back
Top