Link belts stretch terribly, both long term and elastically. ?Also, depending on type, if the V pulleys or belt are significantly worn on the cheeks, the rivets can bottom out on the grooves of the pulleys, which pretty well eliminates the friction necessary for power transmission. ?Use an endless V belt. ?It is only worth using link belts either if you can double them up where doubling would not otherwise be necessary, or you have a big movement on the belt tensioner, preferably with self adjustment e.g. by the weight of the motor hanging on it.
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Eddie
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------ Original Message ------
From: jkling222@...
To: [email protected]
Sent: Saturday, March 16th 2024, 20:22
Subject: Re: [SouthBendLathe] Depth of cuts
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On Sunday, June 25, 2023 at 04:13:48 PM EDT, Steven Schlegel <sc.schlegel@...> wrote:
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Wow. Lots of questions. One fact is really obvious. My machine operator pair should take cuts 10x deeper than I am.
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The lathe head and all associated gearing is good. It was recently rebuilt and all pins, etc. were replaced correctly. Of that I am pretty certain. The drive unit moves freely, was also rebuilt, and operates correctly.?
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Speeds are from the ebay chart I bought. The HSS tools I grind are based upon lots of videos I watch. I bought a jig to help get the angles correct. My carbide are inserts, many are still the original chinesium, but are being replaced by higher quality as they die. I use a Boxer quick change toolpost.
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Now, here is where I feel the problem lies since I do not have the power to make deep cuts:?
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I use a link belt on the motor. It slips especially as oil gets on it. The bearing in the drive unit slings oil. The drive belt to the lathe head is a serpentine auto belt. It seems to transfer power efficiently. The drive unit is mounted on channel so it's adjustable.??
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I am wondering about switching to an auto v-belt for the motor. Next, could the channel be flexing? It is the kind used to support conduit.
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Thanks,
Steven
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What sort of carbide are you using? I've never had good luck with the 0 degree rake brazed carbide. I hear that it wants to run really fast.
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On 6/25/23 14:24, Brandon Corey wrote:
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0.002” is way too low. ?I run 0.015”-0.020” at a minimum for the hardest materials. ?Material? ?Speeds? ?What size is your motor?
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Brandon
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I have a simple question. How deep of cuts do you normally make?
I have a 1949 vintage SB9C, with 6 speeds. I replaced the 1/4 hp motor with a 1/2 HP one. I use carbide a lot, but HSS still gets used some. Many of the videos say I should take at least a 0.005" cut for the best finish. I usually cannot take more than 0.002" with dragging down, or stopping, the spindle.
What's reasonable for me?
Thanks, Steven
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