No, not the way it works. The spring are essentially “balance” against the weight of the carriage and router assembly. If you got spring tension just right (this isn’t 100% true, but it’s close enough for a “hand grenade” discussion), there would be essentially no weight on the belts, and the only thing resisting the belt would be the friction of the pulleys. Mental exercise: take the springs off. Does the carriage feel heavier or lighter if you try and lift it? Heavier. What does the belt work against - that perceived weight. What does the stepper work against? That belt. Stronger spring, less perceived weight, LESS belt tension.
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good point! Ace hardware here I come.
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I understand what you say regarding the belts for a heavier spindle in regards to the weight felt by the belts because of stronger springs carrying that extra weight. Now to my thoughts, I would like to use a makita 2 1.4 hp router (forgot model #) which accepts a 1/2" shank bit (specialized cutting requirement) but my main concern is the extra weight of that router (7.3 lbs) on the Z axis carriage itself. Your explanation that the springs would carry the extra weight for the belts does not include that extra weight on the carriage, correct? I’m not poking holes in your explanation (which I agree with and the fact that my question is differs from Ray’s), I’m trying to expand it for my thoughts and asking if you think the carriage would carry this extra weight (v-wheels, extra torc of the larger router and bits, distance router extends form Axis plate etc.) I think I need a heavier cnc machine for 1/2" shank bits, do you concur? Thanks Randy and MMDV (my mileage does vary).
My point was really about how the springs are a counterbalance, that they don’t make forces on the belts and steppers worse.
What happens with a 7lb router on the carriage? Got me… as you say, there is a lot more weight on the wheels, more torque, etc. There’s probably someone around here with better input on that.
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Spring may help hold the 2.2 kw spindle on the Z axis however, the Y axis stepper motor and belt will still have to push that extra weigh sideways. I’m also guessing that the weight in the middle of the Y axis will cause “lots” of flex (torsion, not just up and down) on the assembly. A .8 kw or 1.5 KW spindle would be more appropriate for this machine. Plus they are way quieter than a router.
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The only reason I’m considering the 2.2 kw is the need I have to use a 1/2" shank bit. I cant get a1.5 kw with an er 20 collet.
Ran a little test.
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What kind of bit do you require the use of, that only comes in a 1/2" shank?
The reason I ask is, larger bits can require quite a bit of force. It isn’t just a matter of a heavy spindle but the forces required to drive that bit through the material.
Obviously one can take shallow passes, but you can still end-up in ruin trying to drive a (for example) 90-degree v-bit through 3/4" of material even .01" at a time.
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so what your saying is just because I can I should! j/k.
3/8" might be sufficient for the panel bits I’m looking to use. 1/4" shank panel bits are not right proportionally for what I’m doing.
I’ve been looking at the Kress spindle that accepts up to 10 mm shank. Problem is looks like the 1050 is on back order???
Anyone care to share their personal experience with the Kress?
Hey Ray, do you have 10 lb springs (two 5 lb) installed for the Buzz Lightyear video ? I also have a need to utilize 1/2" shank bits but not the time yet to delve deeper into the research. I wonder if we’re both planning similar projects, what do they say about grape minds or vines or great minds ???
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stock springs in the video. going tomorrow to get bigger springs. will let you know.