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Discussion Starter · #1 ·
Hello Everyone.
I've been a member of the Router Forums for some time, but just now bought a CNC router and joined this forum.

After a lot of waffling, I have just bought a SainSmart Genmitsu 3018-PROVer Desktop CNC Router Machine. I will only be using it for the occasional household item or birthday gifts, etc., now and then.
The spindle is a 775 motor, 12V~24V, 10000 RPM made for 1/8" bits although I understand 1/4" collets are available.
Am I correct in thinking that running 1/4" bits on this motor might over tax it somewhat? Or is it completely doable - I have a good selection of 1/4" shank bits.

Thanks
 

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Hello Everyone.
I've been a member of the Router Forums for some time, but just now bought a CNC router and joined this forum.

After a lot of waffling, I have just bought a SainSmart Genmitsu 3018-PROVer Desktop CNC Router Machine. I will only be using it for the occasional household item or birthday gifts, etc., now and then.
The spindle is a 775 motor, 12V~24V, 10000 RPM made for 1/8" bits although I understand 1/4" collets are available.
Am I correct in thinking that running 1/4" bits on this motor might over tax it somewhat? Or is it completely doable - I have a good selection of 1/4" shank bits.

Thanks

Hi, welcome to the conversation!

I am not familiar with your particular spindle, but GENERALLY speaking, a router or spindle motor is not taxed simply by adding a larger bit. It is how you USE the bit that may, or may not tax the motor.

Think of a snow shovel. It will pick up a certain quantity of heavy wet snow on the blade. Now pile the heavy wet snow HIGH on that same snow shovel blade, and the handle will bend or break under the LOAD. The shovel BLADE has not changed. The person lifting the snow has not changed. The weight of the snow per cubic inch has not changed. Only LOAD on the handle has changed, by increasing the VOLUME of snow you are attempting to lift.

Your SPINDLE is the HANDLE of the snow shovel.

A router bit can only move through material at the speed at which one blade has moved material out of the way BEFORE the next blade attempts to take the portion of material it was designed to remove per rotation. So a a two flute router bit that scrapes away 1/64" of material with each flute will safely remove 1/32" of material per revolution. If you attempt to force that bit to remove 1/16" or 1/8" of material per revolution, you WILL tax the spindle, as it cannot produce the horsepower needed to move that much material with each revolution of the blade.

In order to "tax" the spindle (read: exceed the rated LOAD of the shovel's handle) you must :

1. increase the cut speed through the material so that each flute must dig deeper and remove more material with each pass. This is equal to piling HIGHER the amount of snow you are attempting to lift on the shovel blade with each scoop. The handle may bend or break under the excessive LOAD.

2. Increase the amount of material each flute must remove per revolution of the bit by using a larger bit. This is equal to replacing the shovel BLADE with a much larger one, but still maintaining the same HEIGHT of the snow LOAD you are attempting to lift with the HANDLE of the shovel. The larger BLADE has added additional LOAD to the shovel handle even though the snow on the shovel is at the same height. The handle may bend or break under the excessive LOAD.

A bigger bit does not tax the spindle as long as you are only putting the same LOAD onto the spindle as the bit rotates. A bigger bit means smaller bites per revolution, which equals a slower cut speed or a shallower pass through the material.

A bigger shovel blade does not tax the handle as long as you are only lifting the rated LOAD of the handle, regardless of how large the shovel blade is. A blade twice the original size will not tax the handle, if you are only piling the snow onto the shovel blade 1/2 as high.

The handle is only taxed, when you have piled too much heavy wet snow onto WHATEVER SIZE blade is attached to the handle. It is not the size of the blade that matters. It is the LOAD you expect the handle to lift that matters.

Now, Grasshopper ... extinguish the incense, and tell that guy wearing the bed sheets to stop ringing that infernal bell! 馃ぃ

I have used a 2" surface planer bit on a DeWalt 611 router (1-1/4 HP) with success, by simply slowing down the cut speed and reducing the cut depth. Thus, the motor was not taxed by the LOAD it was cutting with a bit it was never designed to use.

Joe
 

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Discussion Starter · #3 ·
Thank you, Master.
I promise to follow 'The Path' and stay away from shoveling too much snow.
As MacConfucius says; "Many a mickle makes a muckle." (A saying from the Scottish temple) :rolleyes:
 

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Thank you, Master.
I promise to follow 'The Path' and stay away from shoveling too much snow.
As MacConfucius says; "Many a mickle makes a muckle." (A saying from the Scottish temple) :rolleyes:

I look at it this way. If they MAKE a 1/4" collet for it, then they must think it can handle biit with a 1/4" shank.

Joe

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