Lapidaryforum.net
Gadgets, Gizmos, and Dohickeys => Fixing, Modifying and Refurbishing your Lapidary Equipment => Topic started by: 55fossil on May 08, 2018, 10:38:24 AM
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Anyone out there with an 18 inch Frantom that could list the proper pulley sizes???? My saw seems to cut too fast compared to other 18 inch slab saws I have had. I think maybe one of the pulleys may be incorrect. I would appreciate if someone could list the correct pulley sizes:
motor pulley;
main saw pulley;
shaft drive pulley;
triple shaft pulley;
thanks in advance.... love my olddddddd Frantom
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What is the motor speed? Mine is 1725 rpm
When I get home I will measure them
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Rather than trust what's on someone else's saw, I'd figure them out. The motor and arbor sizes should result in a blade speed that coincides with a mfgr'f recommendation. Now the sled speed is a bit more complicated, but I'd calculate what I had now, and then adjust to slow it down to something in the range of 5 to 10 min per inch. I've heard that 7 min is reasonable speed, but much depends of what you are cutting, how big it is (i.e. how much rock is contacting the blade), and the quality of the blade you are using. The HP saws offer three pulley sizes, and I use the slowest configuration at all times. Time equals blade life and blade life is money saved. Just another approach. Then compare with what another saw is configured to run.
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Jhon; No rush, but I appreciate it. With some new bearings and clean-up this baby is running nice. No new paint, I like the Rat Rod look. Motor is 1750 rpm.
Peruano: I agree on the slow speed, except for really soft rocks and obsidian. But the difference between 5 and 10 inches per minute is huge when you max out the rock vice. This Frantom has a new threaded drive rod and clamps from HP so I know those are correct. So stock pulleys should work as long as the drive belt is not slipping.
PS: While I love my Frantom, I have a 24 inch Covington that just started growling from bad main arbor bearings. I have never had a saw that was so easy to work on. Even taking my time I had the bad shaft bearings out in 30 minutes. Now it will be two weeks while I wait for the new bearings....
thanks all for input.
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Fantom are old saws. I read somewhere that you could speed the blade up on the old ones because modern blades cut so much better. Maybe a previous owner deliberately speed it up with a pulley change? I have a 14 inch in the middle of rebuilding, the folks 9I know claim it's the cats meow!!!
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The motor pully is 2 1/4”
The pully on the blade drive shaft is 8”
The pully on the gear drive is 4”/3”/2”
I usually run on the largest for slower speed about 7 minutes per inch. I will shift the belt down to a smaller pully if I am cutting soft rock
This has been a good old saw for $500
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Thanks Jhon, I will check it out in the morning. Nice thing about being old and retired is slow seems pretty darn fast now..... Just like my women, fast used to be good but slow is better now. Sorry, wife is calling, got to go.......
Orrum, definitely great saws.....
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Well, time to finish the rebuild...... There is one more pulley not mentioned. The arbor that holds the blade has the 8 inch motor drive and also another pulley that drives the 2/3/4 inch gear drive. I need to know what this inside pulley size is so the gears pull the rock vice at the right speed. The second pulley is inside the motor drive pulley on the same shaft if that helps.
Turns out a lot of my pulleys were the wrong size and everything was going way to fast. The 3 1/2 inch pulley on the motor was way too big. But it is still pushing the rock vise at 1 inch in 5 minutes or less. Motor is correct at 1725 and I can live with the gear drive of 5,4,3. I like slow.
The big problem I run across with a too fast saw is the blade cups when you run large, hard rocks. When the cupping gets to about 1/8 inch the saw jams up and the rock has a lot of ridges in the cut instead of a smooth face.
Thanks for all the previous help.
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Hello there!
Don't know if Jhon logs on here anymore. Have an 18" Frantom here that was also "reconfigured" by previous owners.
Ours had a 4" on the arbor to drive the feed drive pulley. Changed it to the smallest 1" ID pulley I could find. (About 2-1/2" OD.) Took me forever to get the 8" arbor pulley off - the arbor had a big groove in it from a set screw that had slipped sometime in the past.