Pulley sort of

redbaron1917 · 20 July 2011, 07:22 PM

Just adapted (jury rigged)

a grooving insert to a current tool and had to try it out.

Wasn't sure it would hold or work properly. I want to make a set of pulleys for my DVII to be. Still unsure if the OD is 50 or 52mm and the bolt 4 or 5mm.

I've seen both so far. Anyone shed light on this?

Anyway, faked a small diameter pulley to test the grooving insert. Seems to work fine.

Best Regards,

Tony Moore

Von Writter · 21 July 2011, 02:45 PM

Looks good can a guy opt for a SAE size bolt though? Anyone coming by my plane with a set of "critical" calipers is likely to get knocked on the head

redbaron1917 · 21 July 2011, 04:19 PM

Of course. that is the oilite bronze bushing that will be pressed in.

AN-3 or AN-4?

Best Regards,

Tony

Von Writter · 21 July 2011, 05:42 PM

Quote:

Originally Posted by redbaron1917

Of course. that is the oilite bronze bushing that will be pressed in.

AN-3 or AN-4?

Best Regards,

Tony

Well my plans call for a 4mm bolt (is it really that small?) so that would be 0.1574" =so if my math is OK an AN-3 (0.1875) looks like the ticket no?

redbaron1917 · 21 July 2011, 06:15 PM

I have seen 2 different drawings. 1 has a 52mm OD pulley and a 5mm ID on the bushing (steel original).

The other has a 50mm OD and a 4mm ID. I lean toward the 52mm OD and 5mm ID.

In your case, I would go with at least an AN-3 bolt.

Best Regards,

Tony Moore

Von Writter · 21 July 2011, 06:21 PM

An AN-3 should be fine considering it is probably a higher grade bolt than was originally used and is in between the 4 and 5mm size leaning toward the 5mm

gipsymoth236k · 22 July 2011, 11:12 AM

Tony,

I sent you an email regarding this topic.

Fokker factory drawings show the bolt to be 5mm with a 5.2mm hole in the pulley assembly bracket. I'll check the pulley wheel diameters next.

Regards,
Gary Sewall

redbaron1917 · 22 July 2011, 06:19 PM

Thanks Gary!

That would have .0078" of clearance on the bolt. A bit sloppy, but probably normal for a non ball bearing style pully.

I didn't see the rest of the attachments initially.

The 5.2mm is for the hole in the bracket. That sounds appropriate for a bolt to slip through.

Scaling the drawing with a known dimension, I come up with 46mm diameter.

You mention 45mm OD I believe for inboard pulleys. This is quite close.

Scaling again for width, I come up with 7.5mm and a 5mm groove width.

Does this jive with your research?

I would have thought skinflint AHGF would have used the same size pulleys everywhere.

It is looking like that is not the case.

Best Regards,

Tony Moore

gipsymoth236k · 23 July 2011, 10:17 AM

Tony,

I've scaled the Fokker-factory D.VII aileron inner pulley drawing that shows two outline circles for the pulley wheels. They come out to exactly 45mm diameter, just like the Dr.I. Unfortunately the Fokker-factory drawing for the aileron outer pulley does not show outline circles, but I scaled their logical diameter anyway to properly fit them into the bracket. The wheel could be either 50 or 52mm in diameter. So, I still wonder where Achim got his "52mm" wheel diameter? I used 50mm in the Dr.I. I'll check my Fokker-factory Dr.I wing drawing of this detail to find out. I think I have it, and will let you know....

Regards,
Gary Sewall

Maxim08 · 23 July 2011, 10:25 AM

Tony,
Watching this with interest.
Regards,
John