Belts for 2 x 72 surface grinder attachment

weo

weo

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Hello all. I recently got a SGA for my 2x72 and when playing with it yesterday was wondering if I have the right belts. I use ceramic belt for hogging off material and these like high speed and high pressure to re-fracture the grit. It's my understanding that SGAs work best when taking of small amounts of material, which (to me) means I'm not 'hogging' with high pressure, so should I be using different belts?
Thanks
 
Thanks, Hoss.
So you're saying I'm worrying too much about not using much pressure.

On a related note, would the best use of belts be using new/fresh ones for surface grinding and initial grinding, and used/older ones for profiling? Or should I be using older belts on the surface grinder and use new/fresh ones for initial bevel grinds?
Or am I overthinking this?
 
WEO - I have been thinking about the possible need to do surface grinding. Can you please post a photo or two of your attachement???
 
I'm certainly no expert on grinding belts. Hoss is correct that ceramic belts run cooler and last longer with heavy (hogging) grinding. It seems that ceramic belts need that (as Weo said) pressure 'n high speed to fracture the grain to keep them sharp. That high speed and pressure isn't available with my SGA. What seems to work for me are the cheaper AO belts for SGA work. Yes, they do get dull, but I can use 2 or 3 of them for the price of one ceramic belt.
 
weo said:
Thanks, Hoss.
So you're saying I'm worrying too much about not using much pressure.

On a related note, would the best use of belts be using new/fresh ones for surface grinding and initial grinding, and used/older ones for profiling? Or should I be using older belts on the surface grinder and use new/fresh ones for initial bevel grinds?
Or am I overthinking this?
Click to expand...
Use new ceramic one and see how long will last and what finish you get .Then compare that with how much last your ceramic belts which you use for grinding blade .. My bet is that on surface grinder they will last longer , regardless of slower speed :)
 
Ken H> said:
I'm certainly no expert on grinding belts. Hoss is correct that ceramic belts run cooler and last longer with heavy (hogging) grinding. It seems that ceramic belts need that (as Weo said) pressure 'n high speed to fracture the grain to keep them sharp. That high speed and pressure isn't available with my SGA. What seems to work for me are the cheaper AO belts for SGA work. Yes, they do get dull, but I can use 2 or 3 of them for the price of one ceramic belt.
Click to expand...
Ken , ceramic grain will fracture even in slow speed .They don t fracture any time while we grinding , they break when tip get dull and make lot of resistance rubbing on steel. Pressure depend of feeding ....
 
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i like the 3m 984 ceramics. the belt bump is very very small. i only take off 5 thousandths at a time, if i try 10 thousandths its hard to keep the speed of the table passing the contact wheel consistent, and the blank gets very hot.
 
I use 60 grit 3m Cubitron II belts on mine with fairly shallow passes and water cooling. I sometimes follow that up with a 120 AO belt.
 
I run slightly used belts over a solid steel wheel, a solid wheel helps brake down the grains. The wheel could be aluminum also. With experience you’ll be able to tell when they stop cutting well.

Hoss
 
I'm not sure how helpful this will be, but I generally run a 120 grit ceramic belt on my SGA when going though a "bulk removal" phase (think cleaning up pieces of a Damascus stack).

When finishing the flats of a knife; I've really been liking the gator belts on my SGA. I'll get it up to around a 320 grit gator finish, then throw the cork belt (400 grit) loaded with green compound on the SGA.

Seems to do a fairly good job.

You can see my progression and results starting at 3:38 here:
 
weo said:
Do you start at 120? If so, why not start at 36-60?
Click to expand...

This is for stock removal:

I do all my grinding post HT (generally 1/8'' stock). Right after the temper I throw it on the SGA and nowadays have been starting with a 220 grit gator belt.... then 360, then cork. The 60-120 seems to just add scratches I have to get off.

I try and take little steps (0.002-0.003). Grinder is running at full tilt which puts the belt at 914 RPM... which I think works out to 5484 SFPM.

Just how I've been doing it... not the gospel for sure.
 
I use the cork with green compound on blades, but never tried it with the SGA. I'll have to try that sometime. Thanks for the idea.
 
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