Post by tereza on Apr 25, 2020 20:57:11 GMT -5
Hi folks,
I recently finished refurbishing and old Lortone ST10 and while doing that I found out that some of the parts are not originals and that the saw has been modified for faster feed speed. I am having several issues with the saw but the main thing I am trying to figure out now is if the feed speed is too fast and how to tell if it is.
The modified parts are the feed screw and components around it (feed nut, collar, bushings, castings,...). Supposedly these saws had originally 3/8-24 thread feed rod and mine looks like 3/8-16 making the feed run about 30% faster. I am not sure what the RPM of the feed motor is, I cannot find any marking but "Brevel products model F".
Regarding the saw blade setup:
Arbor motor: 1725 rpm
motor shaft dia: 0.5 inch, pulley: 2.5inch
arbor shaft dia: 0.75 inch, pulley: 4inch
After talking to HP I decided to get 3" for the arbor shaft to speed up the blade a bit as well - supposedly the blades should handle that fine and it's what they are putting on their small slab saws - I haven't changed the pulleys yet though.
I was warned that this setup might cause significant load on the motors and that I should buy the "original" feed rod - but that also means buying replacement for the other parts that have been modified. Before I decide I really have to spend that money I wonder if there is some way for me to tell if the saw is handling it fine or not. My understanding is that the previous owner has been running it in this setup for quite some time...
I tried cutting a few small jaspers on the saw and it went ok, but quite a bit faster than what I am used to from my lapidary club, both motors, arbor shaft and arbor shaft bearing heated up - the shaft + bearings to about 90F, the main motor to about 130F.
Another problematic thing is that since the feed rod is threaded along its whole length the coupling that attaches it to the feed motor doesn't grip well on the threads and the set screw likes to come loose after just a minute or two of cutting so I have to keep stopping it to reattach it. I tried to fill in the threads with epoxy to simulate a smooth shaft and it helped for about four cuts after which it started coming loose again.
So now I am trying to figure out if I really have a problem with the feed speed and what to do about the coupling (the original shaft was flat on ends so it probably help better).
Any advice/opinions are welcome.
Tereza.
I recently finished refurbishing and old Lortone ST10 and while doing that I found out that some of the parts are not originals and that the saw has been modified for faster feed speed. I am having several issues with the saw but the main thing I am trying to figure out now is if the feed speed is too fast and how to tell if it is.
The modified parts are the feed screw and components around it (feed nut, collar, bushings, castings,...). Supposedly these saws had originally 3/8-24 thread feed rod and mine looks like 3/8-16 making the feed run about 30% faster. I am not sure what the RPM of the feed motor is, I cannot find any marking but "Brevel products model F".
Regarding the saw blade setup:
Arbor motor: 1725 rpm
motor shaft dia: 0.5 inch, pulley: 2.5inch
arbor shaft dia: 0.75 inch, pulley: 4inch
After talking to HP I decided to get 3" for the arbor shaft to speed up the blade a bit as well - supposedly the blades should handle that fine and it's what they are putting on their small slab saws - I haven't changed the pulleys yet though.
I was warned that this setup might cause significant load on the motors and that I should buy the "original" feed rod - but that also means buying replacement for the other parts that have been modified. Before I decide I really have to spend that money I wonder if there is some way for me to tell if the saw is handling it fine or not. My understanding is that the previous owner has been running it in this setup for quite some time...
I tried cutting a few small jaspers on the saw and it went ok, but quite a bit faster than what I am used to from my lapidary club, both motors, arbor shaft and arbor shaft bearing heated up - the shaft + bearings to about 90F, the main motor to about 130F.
Another problematic thing is that since the feed rod is threaded along its whole length the coupling that attaches it to the feed motor doesn't grip well on the threads and the set screw likes to come loose after just a minute or two of cutting so I have to keep stopping it to reattach it. I tried to fill in the threads with epoxy to simulate a smooth shaft and it helped for about four cuts after which it started coming loose again.
So now I am trying to figure out if I really have a problem with the feed speed and what to do about the coupling (the original shaft was flat on ends so it probably help better).
Any advice/opinions are welcome.
Tereza.