Several days ago, I posted about an inexpensive Baileigh bench top DP and was mainly interested in this machine because of the apparent 'electronic' speed variation - trying to understand 'how' this feature can be offered at that price (knowing other electronically speed control DPs ofter sell for $1000 or much more) - SO, looking inside the top (pic below), there is just one belt - thus changing 'pulley' sizes (radii) is not the answer; another thought would be changing the speed of the motor, such as in universal motors inside routers, but my assumption is that an induction motor is used on this DP - any comments would be appreciated. Thanks - Dave
.
03-13-2018, 11:10 AM (This post was last modified: 03-13-2018, 11:11 AM by Dave Mc.)
That is some type of continuously variable pulley transmission setup. It probably has a stepper motor the varies the width of the pulleys making the belt ride higher or lower in the groove.
"During times of universal deceit, Telling the truth becomes a revolutionary act"
(03-13-2018, 11:10 AM)Dave Mc Wrote: That is some type of continuously variable pulley transmission setup. It probably has a stepper motor the varies the width of the pulleys making the belt ride higher or lower in the groove.
Thanks Dave - since I posted and after your response above, I've been googling some articles on CVT using a pulley system - found the GIF image below HERE which gives me a nice visual explanation - assume that is the pulley setup used on the Baileigh DP - now wondering 'how reliable' this pulley mechanism is - assume has been around for a while, but not commonly used in drill presses in this price range vs. the multiple belts? Thanks again - Dave
03-14-2018, 02:47 AM (This post was last modified: 03-14-2018, 02:49 AM by kurt18947.)
(03-13-2018, 12:05 PM)giradman Wrote: Thanks Dave - since I posted and after your response above, I've been googling some articles on CVT using a pulley system - found the GIF image below HERE which gives me a nice visual explanation - assume that is the pulley setup used on the Baileigh DP - now wondering 'how reliable' this pulley mechanism is - assume has been around for a while, but not commonly used in drill presses in this price range vs. the multiple belts? Thanks again - Dave
It looks like a Reeves drive. Reeves drives are/were commonly used on wood lathes. Some had issues but the issues may have had to do with cheap materials (pulleys would wear) and lack of lubrication.
that's the same scheme a bridgeport mill uses to change speeds. They vary the distance between the flanges of the pulley on the controlling end, and the other end has a spring that keeps the tension. Is it really electronically controlled? That is not something I would want. There is a big knob on the side that looks like it might control the speed, if it was electronic they would have used a much smaller knob. Bridgeports have a plastic bushing that gets noisy over time, replacing it is one of the most common repairs made on one of those machines.
I have a cnc bridgeport where the adjustment handle was replaced by an air motor. I always figured that it would be fairly easy to replace that with a stepper. Not sure how the original control decided what speed they were at, there doesn't appear to be a home switch or anything that would serve a similar function.
(03-14-2018, 02:47 AM)kurt18947 Wrote: It looks like a Reeves drive. Reeves drives are/were commonly used on wood lathes. Some had issues but the issues may have had to do with cheap materials (pulleys would wear) and lack of lubrication.
(03-14-2018, 05:58 AM)EricU Wrote: that's the same scheme a bridgeport mill uses to change speeds. They vary the distance between the flanges of the pulley on the controlling end, and the other end has a spring that keeps the tension. Is it really electronically controlled? That is not something I would want. There is a big knob on the side that looks like it might control the speed, if it was electronic they would have used a much smaller knob. Bridgeports have a plastic bushing that gets noisy over time, replacing it is one of the most common repairs made on one of those machines...................
(03-14-2018, 07:28 AM)GlenS Wrote: No info here. Just a comment.
I've never seen or heard of this setup & it's fascinating.
Thanks all for the further comments - spent a couple of hours yesterday reading on CVT (Continuously Variable Transmission) - there seems to be quite a few different engineering designs, so not sure which one is used in the DP under discussion; there is a large knob on the left side (in my first post pic w/ arrows) - would be curious as to the effort needed to turn the knob as the machine is running (recommended in the manual) and also the noise produced - of course, I'm most concerned about reliability - at least w/ multiple belts there is virtually nothing to break but the motor?
I'm also a recent member of the Sawmill Creek forum and there was a Baileigh sponsor's sub-forum there that now seems defunct - however, there were several contacts and email addresses - I sent a couple of messages w/ the same questions above but have not received an answer. Dave
it doesn't change speeds well if the machine isn't running, certainly not increasing speed. Quite possibly damaging the belt if adjusted while stopped. Looking at the picture, I'm really not convinced I understand the exact mechanism, but the rod that holds the top half of the driving pulley looks like it might be a leadscrew/nut arrangement.
(03-14-2018, 04:01 PM)EricU Wrote: it doesn't change speeds well if the machine isn't running, certainly not increasing speed. Quite possibly damaging the belt if adjusted while stopped. Looking at the picture, I'm really not convinced I understand the exact mechanism, but the rod that holds the top half of the driving pulley looks like it might be a leadscrew/nut arrangement.
Hi Eric - I read the manual for the Baileigh DP and the statement was made to ONLY change the speed when the machine is running; basically, the pulley halves change their opening diameter by moving in a reciprocal fashion so that the single belt is maintained under the same circumference and tension - below is a YouTube animation (believe for an auto or other?) - fascinating concept once I understood the principles.
BUT, I'm still concerned about how well this works in a DP and holds up under average use? Dave
(03-14-2018, 02:47 AM)kurt18947 Wrote: It looks like a Reeves drive. Some had issues but the issues may have had to do with ... lack of lubrication.
Shopsmith used the Reeves drive. There is a hole in the sheave into which I drop some sewing machine oil on a regular basis. The manual is very clear about performing this maintenance. Do some research on the Shopsmith to determine durability. The Shopsmith had other issues, but I do not believe durability was one of them, though I may be wrong.
I tried not believing. That did not work, so now I just believe
Here are some supplies and tools we find essential in our everyday work around the shop. We may receive a commission from sales referred by our links; however, we have carefully selected these products for their usefulness and quality.
