Need help on decision. Was sent wrong mill and not sure what to do.

projectnut said:
I think you'll find there's a wide range of speeds recommended by different manufacturers Starrett recommends fairly quick rotation while some other manufacturers recommend somewhat slower speeds. Here's a clip from Starrett.

"(Starrett Co.). Step 1 Secure the edgefinder in a collet or chuck in the machine spindle. Step 2 Set the spindle speed to about 600 to 1000 rpm, and slide the edgefinder tip over so that it is off center."

Some of their older publications recommend a minimum speed of 300rpm. 1000rpm is about as fast as they can go without tearing themselves apart. Over the years I've found them to be less accurate at speeds lower than 300rpm.
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That was my recollection on speeds as well, I wrote 800-1000, but thinking about it some more, I think more often than not, I am probably closer to 600. I usually just leave it on whatever speed the mill is at unless it is way off. I was surprised by B2’s comment of using his edge finder at 50 rpm, so I tested mine and I can’t tell the difference between the wobble and when they kick out until it gets above 100 rpm, and even then it doesn’t look repeatable.
 
@Ischgl99
Ischgl99 said:
when they kick out until it gets above 100 rpm, and even then it doesn’t look repeatable
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I have a Starrett edge finder. Long ago I decided that using high rpm was probably going to increase the wear on it. So I just started using the lower rpm. Typically I use about or less than 100 rpm. Maybe each one of them is a bit different. Anyway yes mine moves off center with about a 0.001" step which is the smallest step my CNC pendant is set up to make. However, you have to be patient and watch for it. Anyway, it has been quite repeatable. My 940M has a lot of backlash and so I have to always use the finder via coming in from the same direction. I find the edge, commonly set the CNC software to a zero position, then back off well beyond the backlash and then move in again in the original direction to find the edge. It always seems to come in at zero or within a few ten thousands of it. If I then back off again and repeat I get the same thing. With my machine I don't believe must of anything that is less than 0.001".

The reason I mentioned the 50 rpm is because that is about as slow as my VFD will drive the spindle reliably. The VFD can vary the speed from 50 up to 1000 rpm ( gear position 1) so that is a factor of 20x in spindle speed, but I have actually never tried to cut anything at 50 rpm. I guess I have never open the cabinet to see what the VFD display says the Hz for a 50rpm or 1000 rpm is actually. Guess I should do that. Also, the max speed is 3200 when the gear on gear position 2 rather than 1.

@7milesup
7milesup said:
I also found my 833T to be quite loud at its highest speed.
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Yes, my machine is quite noisy. However, a large portion of that is the fan motor. A good portion of the time during set up it is only the fan that is turning and it is still loud. I don't think I have noticed the noise level changing much with speed, but it must be a louder. ..... of course I am half deaf and I always try to wear my ear protection ... to save what little hearing I have left. I have thought about putting a thermal cut out switch on motor to switch the fan on and off.....as much of the time the machine is on it is not cutting anything.
 
B2 said:
Maybe each one of them is a bit different.
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That could be, I don't have a Starrett, I think it is Brown and Sharp. It doesn't have a brand on it, so I forget which one I got. With how cheap they are, I never worried about wearing it out, so run them at higher speeds to make it easier to see the kick out point.
 
I agree, higher speed easier to see. I went back to a wiggler, it's so much easier for me to recognize the kick off. Yes it is dangerous, and can scratch your part. But it's easier for me to see.
 
woodchucker said:
I agree, higher speed easier to see. I went back to a wiggler, it's so much easier for me to recognize the kick off. Yes it is dangerous, and can scratch your part. But it's easier for me to see.
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I have both, it depends on what I am doing.
 
B2 said:
@Ischgl99

I have a Starrett edge finder. Long ago I decided that using high rpm was probably going to increase the wear on it. So I just started using the lower rpm. Typically I use about or less than 100 rpm. Maybe each one of them is a bit different. Anyway yes mine moves off center with about a 0.001" step which is the smallest step my CNC pendant is set up to make. However, you have to be patient and watch for it. Anyway, it has been quite repeatable. My 940M has a lot of backlash and so I have to always use the finder via coming in from the same direction. I find the edge, commonly set the CNC software to a zero position, then back off well beyond the backlash and then move in again in the original direction to find the edge. It always seems to come in at zero or within a few ten thousands of it. If I then back off again and repeat I get the same thing. With my machine I don't believe must of anything that is less than 0.001".

The reason I mentioned the 50 rpm is because that is about as slow as my VFD will drive the spindle reliably. The VFD can vary the speed from 50 up to 1000 rpm ( gear position 1) so that is a factor of 20x in spindle speed, but I have actually never tried to cut anything at 50 rpm. I guess I have never open the cabinet to see what the VFD display says the Hz for a 50rpm or 1000 rpm is actually. Guess I should do that. Also, the max speed is 3200 when the gear on gear position 2 rather than 1.

@7milesup

Yes, my machine is quite noisy. However, a large portion of that is the fan motor. A good portion of the time during set up it is only the fan that is turning and it is still loud. I don't think I have noticed the noise level changing much with speed, but it must be a louder. ..... of course I am half deaf and I always try to wear my ear protection ... to save what little hearing I have left. I have thought about putting a thermal cut out switch on motor to switch the fan on and off.....as much of the time the machine is on it is not cutting anything.
Click to expand...
My motor's fan makes more noise than the drive does up to around 3500 or so RPM, it has a bit of a high pitched whine cranked up to 5000 RPM but I haven't cut anything at the RPM.
 
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I am a Precision Matthews customer (1340GT Lathe, 950V Mill, Band Saw and many accessories). I too have had extensively pleasing service and support from them. I concur with the majority of responders, (almost) no matter what the savings, if you had planned to purchase a specific model, you will not be fully content down the road always wondering what it would be like to have the one you originally purchased. Yes it may be a bit more work, but NOW is the time to do that. Don't over think this. Get what you purchased, be satisfied, and be done. Cheers-
 
I notice that many cannot even think of a use for a sub 100 rpm speed. I often use hole saws. They are not just for wood and are very good at cutting holes in steel, but my mill with a 230 rpm slowest speed is too fast even for the middlingly large saws. I would love to have a 65 rpm "granny gear".
Bill
 
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