Consew 206RB rotary hook diameter request.

[LederMaschinist]

I have a favor to ask of the Consew 206RB or equivalent owners here on the forum.

I'm looking for the outside diameter of the rotary hook, and an approximate distance from the point of the actual hook to the face of the collar where it runs against the bushing on the hook shaft as if it were standing on that face upright on a table.  Careful measurement with a ruler would work, but a caliper measurement would be ideal.

If anyone is wondering, I plan on doing something ill-advised and somewhat foolish.  Thanks.

[CowboyBob]

I know what you want to do & It's too large diameter to fit! 

[LederMaschinist]

Lol.  How much too large?

There's room to move the shaft lower either with offset bushings or larger bushings set lower and plenty of room front and back.   I'm lucky it's a small machine because it will fit on my mill.

By the way, did you know a singer 95 will easily do 4.5 spi, and with a little more work will do just under 4?

Edited November 22, 2018 by LederMaschinist

[CowboyBob]

The problem would be you'd need a longer belt.To make the stitch length longer you can drill ot file out the slot so it's longer.There's a difference of .220 on the diameter,so it needs to be .110 from where it is now(it's close but I doubt if there's room),I think it will hit the feed dog if the shaft isn't lowered.the shaft is also larger @ .310 so you'll need a bushing or make a shaft with a larger end & drop it down too.

Edited November 23, 2018 by CowboyBob

[LederMaschinist]

Thanks for the info.  Right now it uses metal flange bearings for the hook shaft that are .500" diameter and the hook shaft itself is .217" (5.5mm). So I could make new .500" bearings and move the hole for the hook shaft up to about .130" before the wall would get too thin on the side of the hook shaft hole in the bearing.  This means I wouldn't have to do any machining on the bed casting itself, and it would be a simple bearing swap with some careful alignment of the new eccentric holes.   I had already planned on changing that swiss cheese belt to an industrial grade timing belt, which will involve changing the pulleys anyway.  So I can just source the proper size belt and pulleys for the new spacing from top shaft to hook shaft.  It's also possible that there's enough slack in the existing belt to handle an additional .220 of pulley to pulley loop circumference without changing pulleys or belt.  Filing the slot for the stitch length is exactly what I did.  The feed dogs have about .225" of travel now and when I pushed the internal lever beyond the slot, I was able to get the dogs walking about .265".

It's weird how some parts are sized in inches and some parts are obviously metric.  And some aren't inch or metric and are something entirely non-standard and different.

It looks like I might have found a 144w204 for the big, heavy duty stuff I want to do.

[CowboyBob]

Ok,this would be tough but you could put an angle on the bottom shaft & keep the belt,the pulley is round & it would probably stay on.

That 144W204 will sew some heavy stuff,most of the parts are still available for it.Some parts are a lot of $$ but it's a great workhorse type of machine.

[LederMaschinist]

3 hours ago, CowboyBob said:

Ok,this would be tough but you could put an angle on the bottom shaft & keep the belt,the pulley is round & it would probably stay on.

That's an interesting idea.  Considering it's just a couple dollars worth of bronze of bronze and a little setup time, it would be a good way to see if the whole plan will work before changing pulleys and belt.  Some quick math (I cheated and drew it up) shows it's going to be half a degree or less of slope to the hook shaft.  I don't think spinning the rotary hook half a degree off axis will hurt function.  I've seen a similar machine on youtube with a bent hook shaft running much further out than that and it stitched just fine.

[Constabulary]

Wild idea I know but yours is wild too  -  how is this. put a good quality tight cardan joint on the hook drive shaft + a support bushing (if needed and you have enough space) and then you only alter the front bushing. Cardan has to be real tight otherwise if could affect the timing I guess. Ya know what I mean?

Have to admit I don´t know how the 206 looks on the underside... Maybe it´s just an early morning brain fart 

 

EDIT

Or is it what Bob mean with an angle? Then I better shut up

Edited November 24, 2018 by Constabulary

[CowboyBob]

Yes,I'm talking about running the lower shaft @ an angle he needs to drop the leftside so the hook can clear & keep the timing belt the same length.