Ok so this is what I am working on

[Prestofan]

Tim: No, the Presto head would not have been original on the Rek-O-Kut - probably someone exchanged it for the original head placed on by the Rek factory.

[Simon]

The ReK O Kut would have had an AUDEX head

and guess what Standard at 8 ohm - I have one here.


My Presto 1d head stamped 8 ohm reads from the leads 4 ohm - which means it is about 8 ohms.

Hope this helps.

[VRCM]

Oh. I missunderstood. I thought the K8 was a rekokut lathe . My Bad.

[Simon]

Presto is a K8

http://www.prestohistory.com/Presto2.html

[VRCM]

Simon- 4 ohms of resistance means 8 ohms of impedence in this case? That means I need to try for 8 ohms of resistance per coil. Also some thing else occured to me--- because there are two coils in parallel, do they need to be out of phase from each other. The top would be pushing while the bottom is pulling-otherwise they would cancel each other out right? I don't know if someone talked about this before or not but forgive me if I am being repeditive.

[Cutterwoller]

I have that Lathe (presto) I also have a spare motor for it! I took the presto motor out and put a Lyrec one in. You can make the belt out of some cylinder shapped rubber.

[markrob]

Hi,

My 500 ohm 1-D meaured about 22 ohms DC resistance. Note that the coils are in series in a push pull arrangment. They are wired in reverse. This makes no difference on the DC ohms measurment, but is essential for proper operation.

I recently re-wound my 1-D for 8 ohms. I had to make new bobbins because mine cracked when I tried to unwind and re-wind them (be carefull if you tear into the head). I used 5/8" molded acrylic rod as the basis for my new bobbins. I can send you dimensions if you are interested. I filled the bobbin with 8 feet of #30 ga. magnet wire (the wire length is more important than the number of turns). Also note, that its tough to get the coil removed from the upper armature. I had to loosen the the springs that hold the armature to the "V" groove to be able to get mine out. At some point I'll post the steps in case anybody wants to give it a go. The head is pretty easy to work with and is well built.

Mark

[VRCM]

Mark-- This is exactly want I want to do! I originally assumed that the coils were in parallel but they were torn from the terminal posts so I really didn't know. I also found the same thing out when I unwound the bottom coil---I broke the bobbin into three pieces (although I super glued it together rather well). I did make one out of thin (.015in) plastic and a piece of straw. I have wire that apears to be approx. 31 gauge wire. I wound it on to the bobbin and I probably maxed it out at around 8 ft or so. I had already unrolled 128 feet which I thought would be right (obiously a miss calculation). I will unwind it and find out. I would definitly be interested in specs on the bobbin--I have a lathe I could machine them on. Now how did you determine that length of wire (8 ft)?

[VRCM]

Now when it comes to the upper coil you don't need to loosen the spring screws (the manual said it was a bad idea). The entire spring assembly can be taken off of the main plate and then the top coil slips right out. That way you don't need to mess with the springs. Maybe your head is different. Here are some pics.
http://guadalajara.es.craigslist.com.mx/wan/1010528679.html

[VRCM]

Lewis D-- How was the original motor installed? Do you have pics of the original installation and or the modifications? I don't know how any of it went together becuase they ripped out everything--even the wires and switches. Also do you now of a type of motor I could get in America that would work?

[Cutterwoller]

Hmm, I got it from America and they guy took pictures before sending it. Not sure if there was one of the motor. My lathe came all in bits and pieces aswell. Also the motor shaft was bent. I put it back together partly using logic and with a bit of help from the presto 8GV Manual. pm me so I can email you stuff to help you. Do you actually have the motor?

[Simon]

Here is a modified one off the Presto History Page





There are some pictures on Dr Dubs for sale page.

This lathe was sold.

http://www.drdub.com/presto/html/drdub_forsale.html









Off topic there is even a pic on the Amp I purchased in this list.

[markrob]

Mark-- would be right (obiously a miss calculation). I will unwind it and find out. I would definitly be interested in specs on the bobbin--I have a lathe I could machine them on. Now how did you determine that length of wire (8 ft)?

Hi,

I got the wire gauge and length from an 8 ohm 1-C head head I also have. I decided to use the 1-C for my experiments adding motion feedback. So, I removed the coils and unwound them to determine the length. Thanks for the tip on getting to the top coil. I should have done that first before removing the springs!

Here are the dimensions I measured for the bobbin. Center hole - .180" Outside diameter of center hole - .215" Diameter of bobbin - .600" Width of bobbin - .125" Inside diameter of bobbin -.100"

I made my bobbins on my Craftsman 6" metal lathe using a .040" wide cutoff tool to cut the inside area of the bobbin. Molded acrylic rod stock worked great. I also used the cutoff tool to part the finished piece from the acrylic rod stock when complete. I drilled an .060" hole with a Dremel near the center of the bobbin to feed the wire. I wound the coil before the final parting while the still in the lathe. I used my backgear to run the lathe slowly and guided the wire by hand. I also added a bead of Duco cement around the coil to help seal it (dipping in varnigh might be better). I finish it off with a .100" wide strip of masking tape about 2" long. When I re-assemble everything, I re-gap the poles using 4 small strips of .005" paper between the laminated poles and the armature. I set the stylus holder at a right angle to the front edge of the frame via the sprigns using a square and 1/16" drill blank before I gap the head. Finally, I tack the bobbins to the pole pices using Duco (make sure they are centered on the armature). You can PM me if you need more help. Hope this makes sense.

Mark

[VRCM]

I had been on the drdub page but I did not see this part. Thank you. I would probably set up something similar to the first pic from the history page. Theoretically I could put any motor in there as long as I use pulleys to get it to the right speed. Electronically would be difficult unless I actually had the original motor. Maybe three different pulleys: 33, 45, and 78?