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Curiosity - anyone seen a home brew solution for a CNC saw stop system?

JasonPAtkins

Hot Rolled
Joined
Sep 30, 2010
Location
Guinea-Bissau, West Africa
I don’t have time to do anything about this right now, but curiosity got to me as I was looking at my saw the other day. I’ve seen some really nice looking commercial setups (TigerStop, maybe) for CNC cutting stops for chop saws, band saws, and the like. The one I saw could program multiple cuts, and then each “go” button press would cycle the stop to the next length – pretty slick. The prices were pretty impressive too! Easily justifiable for a commercial shop, I’m sure, but for my little non-profit school kind of breath taking.

The functionality there isn’t all that complicated. I’m wondering if anyone has seen a homebrew solution on an Arduino or R.Pi or something like that? It wouldn’t even need to be that accurate (in terms of normal CNC accuracy in the thousandths, I mean) to be very useful. Has anyone rolled their own?

At the very least, I want to get a movable, lockable stop that at least reads on an embedded tape, like the fence on a table saw, but the computerized idea would be pretty cool!!
 
It would need to be accurate to a few thousandths if you intend the positioned to return to the same place so that you can cut another batch of the same part.

Tigerstop guarantees .010", which in my humble opinion leaves something to be desired for repeat positioning. For a home shop you're probably better off to simply add a DRO and position the stop yourself.

Mind you, what may not be apparent is that if you want reliable results the saw itself must be very sturdy and must be capable of holding position, it must carry a sharp blade full kerf and have large, accruate blade stiffeners to keep. If not, than the accuracy of the position is not all that meaningful.

This saw is typically a few thousand USD to 10k+

Furthermore the positioner must be mounted in a fashion in which the distance between the saw and the stop remains hard fixed. I built an outfeed table which is bolted to the floor and stiff, the saw is bolted to the floor as well.
 
It would need to be accurate to a few thousandths if you intend the positioned to return to the same place so that you can cut another batch of the same part.

Tigerstop guarantees .010", which in my humble opinion leaves something to be desired for repeat positioning. For a home shop you're probably better off to simply add a DRO and position the stop yourself.

Mind you, what may not be apparent is that if you want reliable results the saw itself must be very sturdy and must be capable of holding position, it must carry a sharp blade full kerf and have large, accruate blade stiffeners to keep. If not, than the accuracy of the position is not all that meaningful.

This saw is typically a few thousand USD to 10k+

Furthermore the positioner must be mounted in a fashion in which the distance between the saw and the stop remains hard fixed. I built an outfeed table which is bolted to the floor and stiff, the saw is bolted to the floor as well.

Thanks for your thoughts. Yeah, my Wells saw already includes bolt holes on the back that can be used to attach my infeed roller stand, so if the stop were attached to the roller stand, you'd have a rigid assembly attached to the saw.

Obviously the stop system can't make a saw more accurate than the saw already was, but it would be at least as repeatable as scribing the cut line on the stock and lining that up behind the blade, which is the alternative for most people.
 
If you are not fixated on cnc, this would be pretty easy to do in other ways. The Warner and Swasey AC and AB line used contacts and relays, and they were good for a thousandth or less. Instead of entering numbers you moved trip dogs. Wasn't very difficult :)

I can imagine doing this with air or hydraulics or even mechanically, but you have to decide how to move the stock first. Then the method to control the motion will present itself.
 
One of the guys here did a pretty good one IIRC. I want to say it was jim rozen? Try a search. I don't remember if it was just a stop positioner or if it actually unclamped, advanced and reclamped the stock.
 
Get a better scale and learn how to read it. Wood moves as it is cut and the operator can only push so hard to try to keep material against a stop or fence. I had a Whirlwind chopper with a Tiger fence. Two years later it was gone.
 
Chop saws are used for more than woodwork. I have an Omga and I believe they, along with most other industrial brands are geared toward sawing aluminum extrusions to length. That said, wood does not change in length and if it is moving as described than the preparation is suspect and should be evaluated.

By the time wood is on the chop saw in my shop it has adjusted to the shop humidity, has been jointed, square edged and thickness planed. Hand pressure is enough to clamp it.

I’m lost as to what learning to read a scale has to do with the post, no different than adding a DRO or CNC capacity to any other machine. Accuracy is often the fastest path.

Whatever is being cut the steps taken to prep the saw are the same, the cut must be precisely square and the stop must be compared to measurement standards. I find this simple enough. I square the saw then compare measurements to what my longest calipers read.
 








 
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