Anyone have an import dividing head? BS-0 or similar?

[WobblyHand]

Is there any difference between the bs-0 from PM and a bs-0 from one of the generic brands? There is a large difference in price. Willing to pay more for quality, but can't find anything different

In my opinion, yes. I had a generic one, and returned it. It had been dropped and had internal damage. It wasn't packaged properly. The machining was inferior and had razor sharp exposed edges. The gradations and numbers had very sharp edges. The interior was filled with grinding debris and machining swarf. All of which I might have forgiven, save for the internal broken bearing casting which cannot be sourced. It was a fight to return it, the seller making up excuses, or asking me to attempt repair at an offered hourly rate of less than $2/hour. Finally I had eBay step in and they told the seller to refund my money.

In contrast, my PM BS-0 was double boxed. The internal styrofoam was precision cut and tightly fitted to the BS-0 and accessories, preventing any shifting whatsoever. The generic one had ill fitting generic styrofoam which did not immobilize the 52 lb block of iron from moving about. The fit and finish of the PM unit was superior. The markings and gradations did not cut your hands. The rotation was smoother. It was a vastly superior device.

All that being said, I'd bet they were made in the same factory. The internal boxes look nearly identical. But the generic one failed QC, and the PM one didn't. The PM one got superior packaging. Although it cost more, I am extremely happy with my PM BS-0. Maybe you will get lucky with a generic one. More likely not.

 

[WobblyHand]

I bet the plates are slightly different in thickness or something- but it does look like a hokey assembly- what holds the spring in place? Nothing, as far as I can see
Time for a re-design- why not use a regular wire spring? No room?

It is hokey. Nothing really holds it in place. What do you mean by a regular wire spring? Like just a spring whose end loops are attached to each other? Encircling and fitting in the groove?

 

[markba633csi]

No, never mind. I was thinking of a short compression spring but it won't work in that location. Drat
I see what the spring is supposed to do, but
Oh wait- what you need is a large wavy washer! without a cutout-- right? Springy like stainless and thin

 

[WobblyHand]

Here's a picture with the crank off and the arms separated. You can see the washer will foul the spring. I don't quite know how one would do it , but one could make the spring a smaller OD. Maybe the washer OD can be reduced as well.

 

[markba633csi]

I was thinking something like this wavy spring washer- wouldn't the crank hold it in place or does it need to fit in to the groove?

 

[WobblyHand]

I was thinking something like this wavy spring washer
Lots of companies sell them- Fastenal and many others

Think one needs a split wavy washer to get it to fit. (Or cut it?) There is a groove that the current spring fits in. Was just looking at them on McMaster. Need to measure the groove ID, the OD and the height needed. Yeah, (I) need to measure all that!

 

[BladesIIB]

I have the PM BS-1 dividing head and my spring moves around freely with the arms so they are not pushing it off. Seems like your just got to tight in the notch and does not want to spin freely anymore. Maybe see if the edge got a burr or is catching? or if something is caught in the slot. That may explain why it worked before you took it apart and not now? Good luck.

 

[markba633csi]

On second thought I don't think that wavy washer would work. The crank would drag it around and the sector arms would move
It has to engage the groove so it stays put when the crank is turned. Goofy setup- hard to improve on with the space constraints
Yank off the plates and crank and put a proper stepper motor I say

 

[682bear]

My PM BS1 doesn't have the washer under the phillips head screw... the screw head seats into a counterbore in the arm.

Is the washer really necessary? If not, remove it, maybe?

My BS1 has turned out to be a very decent accessory... I'm very happy with it.

-Bear

 

[Windsurfer]

... The machining was inferior and had razor sharp exposed edges. The gradations and numbers had very sharp edges. The interior was filled with grinding debris and machining swarf.

All that being said, I'd bet they were made in the same factory. The internal boxes look nearly identical. But the generic one failed QC, and the PM one didn't. The PM one got superior packaging. Although it cost more, I am extremely happy with my PM BS-0. Maybe you will get lucky with a generic one. More likely not.

So was the one from PM deburred with the sharp edges removed and was it free from interior debris and swarf ?

Aside from the shipping damage, was there any material difference between the two ?

Can you be specific about what failed QC? Assuming the cracked casting was shipping damage, was the damage apparent without disassembly ?

Thanks,
-jd