I have a (+/- 2000) Seiko STH-8BLD.
I have read the following at ( https://leatherworker.net/forum/topic/71217-consew-206-rb5s/ )
Prior to the 90s when Consew went bankrupt Seiko manufactured the 206RB for Consew. They started selling the STH-8BLD machines in North America in 2000 with their own name on them.
Soon after, a new Consew company was formed and they started making 206RB machines in China.
My point being is that Seiko uses the same split bolt for the flywheel. I found, at the local Rona building supplies (Lowe’s in Canada) that it threads into a M7 x 1mm nut. I bought a few M7 x 1mm x 25mm bolts (& 7 mm washers) and tried to thread them into my machine. No dice.
So now what… I decided that the split in the bolt must be there for a reason… it is.
I cut a split in my new bolt in the middle using my Dremel tool (just like the original part) and found it fits perfectly. However, it was a hex head bolt so a socket was too big to fit inside the aluminum positioner collar. So I used the Dremel tool to cut a slot in the bolt’s head allowing it to screw with a slot screw driver. Longer bolt problem resolved.
I found there was too much slop in the collar which allowed it to be off centre. To resolve this I used my pluming pipe cutter to cut a piece of copper pipe just long enough to shim the collar to be close to the correct size. I found that the collar was slightly bigger than the copper pipe’s inner diameter. I used the Dremel to cut a slit in the pipe’s circumference (think a C where the ends of the line almost touch). Now this copper pipe slides over the needle positioner collar.
Almost a perfect fit… but the collar with the copper C shim was just slightly loose. Now this part isn’t a perfect solution, but since I don’t have a metal lathe… I wrapped Scotch tape around the copper shim 2-3 times. I started with the end of the tape in the copper slit and finished with it in the slit. I then carefully cut the tape flush with the end of the collar. The collar now fit snugly into the middle of the hand wheel.
Now the easy part… I threaded the bolt through the middle of the collar with a couple 7mm flat washers between the bolt and the positioner collar. The tape ensured it was centred in the hole of the hand rim.
I bought a Reliable Servo motor and positioner. If you have a different Servo motor then you may need to adjust the instructions I’ve provided. It included an aluminum collar for the positioner.
I haven’t done anything big yet, just configured and tested the system. It sews super slowly at the lowest setting and it has no problem with thick leather at the slowest speed. If I have it set to stop with needle down, the needle will go to needle up if I push down with my foot on the foot pedal.
This may be different with your Servo motor. I can’t say they’ll all go up when you push down with your heal. Initially mine didn’t because my linkages were too tight to allow the pedal to push the lever on the servo motor up.
With a bit of practice, I can now tap the pedal and the machine will stitch one stitch at a time. With it set to needle down it will stop in the down position allowing me to turn the material without it shifting. Once I’m done with the line of stitches I can press down with my heal on the foot pedal and it lifts the needle allowing the material to be moved out.
Hope this helps.
John
