coarse feedscrew for Presto K8

[Brother Mack]

Hi, I have a working K8, it has a fine feedscrew, would like to know if it is possible to switch that out for a coarse feedscrew. I want to have a single 3 minute song per side.

[emorritt]

I have two K recorders and the mechanism under the turntable isn't a feedscrew, but a fan gear (I think that's what it's called) with a drive gear that moves the cutting arm across the surface of the record. Later units came with three different drive gears that provided different LPI - I don't recall the pitches - but they ranged from coarse (78) to microgroove (LP). I think the machine I have with the interchangable gears is a K10; I'm not sure that the drive gear on the K8 can be changed out, without looking at both machines. The 5C head on my K10 has an advance ball (polished steel - not jewel) assembly attached to it for use with the microgroove drive gear. The 10 and maybe 11 series machines are the only ones I know of with interchangable drive gears, because at that late of time for that series of machines, microgroove had become a big deal. Earlier machines were pretty much designed for coarse groove 78/33 operation only.

[Brother Mack]

Thanks! Yes, mine is definitely not coarse, getting about 6 minutes per side of a 10" pvc. It's a 1936 model.

[Jesus H Chrysler]

Six min per side on 10" @ 33 rpm is standard pitch for K's, 112 lpi. The k-10 has 112 and 224, outside in and inside out, but afaik, those are the only available groove pitches.

[emorritt]

Let me dig out my K10 and take a look under the turntable; I seem to recall three gears. One would be on the shaft in use and there (I think) were two little 'posts' that held the other two. I'll see if the pitches are stamped on them. When I got the machine years ago, it was the first small-format machine I had ever seen that had an advance ball on the head. Once I got into it and discovered the multi-pitch feature it made sense then for the microgroove pitch.