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Author Topic: Gravity Feeding Slab Saws  (Read 293 times)

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StillRockinPdX

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Gravity Feeding Slab Saws
« on: August 05, 2017, 01:00:17 PM »

     Does anyone know what amount of weight one should use on the various types of rocks? I mean how do you know when the right amount of weight has been added to your gravity pull rope? Will you know pretty much straightaway if it is in adequate or overweight?
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peruano

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Re: Gravity Feeding Slab Saws
« Reply #1 on: August 05, 2017, 01:19:22 PM »

There is no fast rule, because of so may variables.  With a power feed saw I try for speeds between 1" in 5 min to 1" in 7 min.  Whether you can duplicate that with gravity is unknown to me.  You are try to keep the rock in contact with the blade but not crowding it.  Clearly the amount of weight will depend on rock size and hardness. I'd play with little specimens until you get the hang of it.  I have used water bottles hanging on the cord so that I can easily adjust weights as needed. 
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StillRockinPdX

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Re: Gravity Feeding Slab Saws
« Reply #2 on: August 05, 2017, 01:25:16 PM »

Okay. Water bottles sounds like a great idea. Was just going through stuff looking for something to hang from the feed tray rope. Also I forgot to get the stp additive. Off to the store before I waste fresh mineral oil.
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vitzitziltecpatl

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Re: Gravity Feeding Slab Saws
« Reply #3 on: August 05, 2017, 09:08:04 PM »

Another thing to keep an eye on is your vise. Many will rise up if the feed rate is too fast. Too much weight and it might pull the stone into the blade faster than the blade can cut. If so the vise can rise up during cutting causing binding, or at the least a slab with inconsistent thickness.

Some saw vises have design features to keep them from rising up, but my old refurb HP 10" does not.

Rockoteer

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Re: Gravity Feeding Slab Saws
« Reply #4 on: August 06, 2017, 11:18:44 AM »

Just trial and error, trial, trial and error until its trial and success.
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55fossil

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Re: Gravity Feeding Slab Saws
« Reply #5 on: August 06, 2017, 11:39:37 AM »

    I hope M*****  will jump in on this.  Vices should not rise.   Everything wears on a saw but you should adjust your saw vice so that the table cannot rise or tilt when you pull on it. You should have just enough tolerance on the slide bars or rails for the vise to move smoothly but not lift in any direction. Most vices have bolts for adjusting this.

   I know M***** keeps his saws so tight you would think they are >>> well, you know the type.  very tight....  Hope he does not mind me throwing him into this convo but he is a reliable source.
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vitzitziltecpatl

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Re: Gravity Feeding Slab Saws
« Reply #6 on: August 07, 2017, 08:01:28 AM »

The little vice carriage on our HP 10" is one of those that rides on a single rail, and can be rotated up and away from the table so it isn't in the way during use as a trim saw.

Have seen variations on this type carriage designed to keep it flat, but don't remember who made them.

55fossil

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Re: Gravity Feeding Slab Saws
« Reply #7 on: August 07, 2017, 10:01:11 AM »

ooooh, that kind of vice.  Guess I would just go with a low feed rate and be happy.
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MilanJoe

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Re: Gravity Feeding Slab Saws
« Reply #8 on: December 01, 2017, 11:51:11 AM »

The little vice carriage on our HP 10" is one of those that rides on a single rail, and can be rotated up and away from the table so it isn't in the way during use as a trim saw.


Thanks for mentioning that!  I recently acquired an old HP E-10 and I didn't ever think to rotate the vice carriage. I was thinking 'Crap, this can't be used for trimming.'  Duh!
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lapidaryrough

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Re: Gravity Feeding Slab Saws
« Reply #9 on: December 01, 2017, 12:11:45 PM »

 ''old HP E-10 and I didn't ever think to rotate the vice carriage.''

  you mean the wood clamp sliding on brass rod under vise. with a  3/8 shaft. that one.

  cable ran over a  1'' wheel on right and had a counter weight on end. as sold in 1955 for my unit.

  and the unit was sold with a black diamond blade ( 9'' ).  Highland park label

  myself i don't used the side weight waste of time ... to much sanding refacing time . best to use a slab saw. saves on waste refacing.
high speed cutting x waste. $$$ in mud.

  Jack

 

 
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lapidaryrough

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Re: Gravity Feeding Slab Saws
« Reply #10 on: December 01, 2017, 12:21:11 PM »

found  photo of  E-10  this one is a 1955
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MilanJoe

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Re: Gravity Feeding Slab Saws
« Reply #11 on: December 01, 2017, 12:38:15 PM »

found  photo of  E-10  this one is a 1955
This is my E-10. Not sure what vintage it is. Just added 3 wheels to it. I haven't cabbed in over 10 years, but it's time to get busy again!
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vitzitziltecpatl

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Re: Gravity Feeding Slab Saws
« Reply #12 on: December 01, 2017, 07:15:27 PM »

Looks like you're all set to get going again.

The HP 10" saw we have looks identical to the saw on that unit. The saw was refurbed by Cigar Box Rock and came to us with an 8 lb. trolling downrigger weight for the gravity feed. Using a good blade it cuts smooth as glass.

If you need to slow the feed rate you could use a lighter weight. Have seen people use cans of concrete with an eye bolt set in them, but even a jug of water will work. Add or remove water to change the weight as needed.

There was another brand of saw vise that had an additional rod or cable to keep the carriage from riding upward, but I don't remember who made that one. I sometimes add a little extra weight to my carriage, but if you slow the feed rate it should eliminate that problem too.

Happy Cutting!
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