Spindle proposal

[fpworks]

I have an idea for driving a Sherline spindle. (not on a Sherline mill)

Directly mount the below motor to the spindle shaft with a two-way flexible shaft coupler, eliminating the belt drive. I should be able to align the shafts to within 0.05mm, both in parallelism and position.

http://www.grainger.com/Grainger/pro...762111&ccitem=

I would have to make a custom bracket and sheave for this motor to work with a pulley arrangement anyhow...a direct connection would be a bit more simple, and the 1:1 ratio is perfect.

Any advice is appreciated,
Justin

[ViperTX]

1 to 1 coupling is always possible...just need a motor with more torque then one which has a pulley or gear giving it some mechanical advantage.

[JFettig]

A direct connect would be nice, except if you have to get at the drawbar.

I bought a 1.5hp DC motor off of ebay for about $200 and I would suggest that to ya over the one you have listed there.
http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWA:IT


Jon

[fpworks]

About the drawbar...I'm swapping my Sherline Morse spindle for an ER16 spindle, so no problem there. Sorry...forgot to mention that I already had that covered.

I'm cutting aluminum with small endmills (1/8"), so I shouldn't have to "gear down" for more torque with the motors that I'm considering.

Jon,
Do you have that motor up and running? How has it worked? I know of some industrial firms that push Dayton motors quite hard and long, with very good results.

[JFettig]

I havent gotten this motor hooked up to the mill yet, I still need to finisht he mounting plates and make a double pully.

You may need to change the bearings or release some of the preload on the spindle bearings for those speeds.
This is a dayton motor or the one your looking at is a dayton motor?
mine is 2.5hp 'treadmill duty' and 1.5hp continuous duty wich is what I will be running it at.

Jon

[JRoque]

Hello. Slightly off topic, what is the advantage of using that particular motor over a router motor? I recently bought a Porter Cable 3.25 HP router for $285. Other routers with ~2 HP motors go for around $150. These motors are also universal type and they come with collet holders that can couple directly to your spindle shaft.

Julio

[JFettig]

I am using it on a mini mill with a quick change tooling system. I dont think a router would stand up to the load I put on it and I need a low enough RPM. I think this motor is more suitable for the job.

Jon

[ViperTX]

JFettig, must an FYI....If you check the other spindle related thread, I found that same motor for about $40, it's a treadmill motor and a new controller from Grainger is under $100.

[JFettig]

Yes, I did see that, the motor is actually $19.99, you looked at the wrong one next page top Yes I know, the reason I am refering to this one is that its already set up and ready to go.

[fpworks]

Yes,
That treadmill motor may be a better choice. I would think 1.5 hp continuous would be plenty...and some. Please keep us posted when you install it.

The Dayton motor I saw in action was not the same...I saw a 1/2 hp version, running at very high load for 1.5 hour cycles. (don't know % load, but you could hear the rpms falling off)

I've already backed off the preload on my Sherline Morse spindle for the rpms...however, I don't like having to keep such a close eye on belt tension for vibration at those speeds. This is why I am most interested in the direct connection. When I pick up an ER16 spindle variant, I may choose one with a cogged timing belt sheave.

[Swede]

This thread has a great interest to me, as I have been adapting a number of unusual motors to a Sherline "Industrial" ER16 spindle for my bench CNC mill. The original retrofit motor I tried was a 17,000 RPM Dayton AC/DC motor, supposedly 1 HP. I'm pretty sure it came out of a vacuum cleaner... it was LOUD. TOO loud. It was also a unique surplus that I found at a local store, and if it dies, I was out of luck.

I'm currently deep into retrofitting one of the ubiquitous 4/5 HP Chinese "mini-mill" motors, as these are dirt cheap and plentiful. The mini-mill motor tachs at 7,000 RPM, and I am planning on using some step-down to achieve 5,000 at the spindle.

One thing which I have done is to turn some new pulleys from aluminum which allows the use of TWO of the stock Sherline belts simultaneously so the system can handle the higher speeds and HP. The motor is mounted on a plate which runs on a small THK RSR12 rail, and a 1/4" leadscrew allows quick and on-the-fly adjustment of belt tension, which seems pretty important at 10,000 RPM.

I really like the direct drive concept, and I think BOTH of these motors, especially the Grainger job, look really primo. I wish the Grainger motor was just a bit cheaper. Top quality, but $200+, ouch.

Anyone else adapted faster/higher HP motors to a Sherline? I think the Sherline ER16 spindle shows a lot of promise for retrofit, especially if fixed Z tooling is used.

[JFettig]

I just made a 2" pully for my spindle, a double pully that will go along with the 2.5" pully on my 1.5hp motor

I plan on making a 2.5 and a 3" pully later on, simple change in the program on the cnc

Swede: I am running that same motor belt drive 1:2 so 3000 or a little more at the spindle and its running quite well, I ran it 1:1 at one time and hardly had any torque to do much.

Hopefully at 8000rpm Ill be ok with mine

btw, the guy who I bought my motor from said it runs 130v 8a and 6500rpm at that.

Jon