[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

[Swede]

Jon, can you describe again the condition which resulted in poor torque at the tool? I understand it was a 1:1 combo - which motor and RPM? The treadmill job? Thanks.

I am hoping that the mini-mill motor will be acceptable, as it is going to deliver more torque to the Sherline spindle than it ever did to the stiff, gear-head mini-mill R8 job.

[JFettig]

Well I couldnt take the same depth of cuts and was affraid to crank up the feed rate to match the rpm. I havent hooked up the threadmill motor yet, but I made my 2" pully for it so far, still have a couple more to make to try out. Im hoping Ill have enough torque to drill at lower speeds with this 2" setup so I can get maximum speed out of it.

It was the stock motor that I still have hooked up a 1:2 ratio now so Im running the spindle at half the motor speed.

Depends on the size of cuts you want to take and all, you should be ok.

Jon

[fpworks]

I'm starting to narrow down my spindle options. As Swede has said before, there is a huge void in options here.

Swede,
Got a question for you. You said on your website that the Sherline ER16 spindle was capable of going 0.06" deep @ 4ipm, otherwise you got some sort of bearing noise/binding/vibration. (can't remember specifics)

Can you tell more details on the conditions that caused this problem. (work material type, endmill size/flutes, and rpm?) Do you think upgrading the spindle bearings to ABEC-7s could help this condition?

These bearings cost much more than the spindle...I'm trying to decide on whether to give up on the Sherline spindle idea, or move up to a more elaborate/expensive spindle. The Sherline spindle remains attractive because of relatively low runout and it bolts on to my Minitech mill.

Thanks,
Justin

[ViperTX]

I'm starting to narrow down my spindle options. As Swede has said before, there is a huge void in options here.

Swede,
Got a question for you. You said on your website that the Sherline ER16 spindle was capable of going 0.06" deep @ 4ipm, otherwise you got some sort of bearing noise/binding/vibration. (can't remember specifics)

Can you tell more details on the conditions that caused this problem. (work material type, endmill size/flutes, and rpm?) Do you think upgrading the spindle bearings to ABEC-7s could help this condition?

These bearings cost much more than the spindle...I'm trying to decide on whether to give up on the Sherline spindle idea, or move up to a more elaborate/expensive spindle. The Sherline spindle remains attractive because of relatively low runout and it bolts on to my Minitech mill.

Thanks,
Justin

Just a thought....we can speculate all we want, but it might be better to just ask Joe Martin (Sherline) what we are attempting to do. The best I can tell is those bearings in the Sherline spindle are very low in the ABEC numbers ...just guessing again based on the info at LittleMachine's replacement parts list.

[Swede]

Justin, don't interpret those numbers to mean anything. Those tests used a stock Sherline and motor setup. There's a good chance the RPM was not especially high.

My gut feel for the Sherline ER16 spindle is that properly setup, with a rigid machine, and the spindle at 7,000+ RPM, it could do respectable work in aluminum and softer metals. The bore of the Sherline is ground accurately, and if one wanted to work on it, the bearings probably could be replaced, correctly preloaded, and it'd be even more capable.

I like the concept of a direct drive, although I don't have a lot of experience in that area. I'm not sure what torque and RPM a coupler like a steel bellows, Oldham, whatever, could handle. I think balance requirements will skyrocket approaching 10,000 RPM. Even assymetrical set screws on a coupler could cause grief, with the vibration being transmitted to the cutter, and short bearing life.

There is a titanic gap in spindles for the small-mill home market, with Sherline ER16 and mini-mill spindles at the low (affordable) end, and an HF spindle like a Hofer or Kavo at the high end. Even a basic HF spindle setup is many thousands of dollars new.

Here are two spindles which I think have some potential for the home mill:

The Finley 50-13. http://www.finleyspindles.com/50-13-spindles_desc.htm
I think the long housing, cartridge spindle, at IIRC about $1k would be the heart of a really nice high-speed bench mill, uses ER20 collets.

There is a German spindle at
http://www.profimaschinen.de/spindel...eleinheit.html
Which looks VERY nice and the price is not much more than a Sherline. ER25 spindle, nice capacity. Any German friends out there with experience or more info? The German block spindle at 449 Euros is attractive. It even comes with a timing belt pulley installed.

[ViperTX]

Darn, maybe I misread the Air Spindle price..I thought it was about $1K for the air motor and about $800 for the spindle...anyway did you see the 35 CFM air consumption and the spindle runs at 3300 RPM underload...the German spindle seems more attractive....if we could only read the info.

[fpworks]

Swede,
Thanks for the information. I'm trying to see into the future and eliminate potential problems of putting an oversize motor on a Sherline spindle, just to have more problems and downtime, rather than tossing out a couple thousand dollars on the table right now for something that should be reliable and better performing.

I found something that has my attention...a SM-C73 Fimec router spindle from www.ekstromcarlson.com.

http://www.ekstromcarlson.com/router_packages.htm

Points:
+ 2.68 hp @ 18,000rpm
+ 1.75 hp @ 12,000rpm
- min speed of 7000 rpm
- requires 220 VAC (not really a minus)
+ BRUSHLESS AC motor
+ ER collet system (I think ER20)
~ 0.0004" runout
+ claimed to be quiet
+ 11 lbs
+ built-in cooling fan
~ $1900 for spindle/motor/reactor/drive (new)
+ no belts/drive fabrication
+ industrial quality for continuous operation
? too fast for 4 mm spot drilling in aluminum? (haven't thought about this)
? too much spindle for my Minitech mill?

I am thinking really hard about this one. Expensive, but I don't see too many alternatives. Does anyone see a disadvantage to this spindle?

[Swede]

Darn, maybe I misread the Air Spindle price..I thought it was about $1K for the air motor and about $800 for the spindle...anyway did you see the 35 CFM air consumption and the spindle runs at 3300 RPM underload...the German spindle seems more attractive....if we could only read the info.

I personally would buy just the spindle, skip the air motor, and drive it with a universal AC/DC motor, looking for 10K or so RPM, or perhaps coupling it directly to a similar motor. I'd be concerned about torque at lower speeds though with a direct setup. When you engineer for pulleys, you always have the option to swap pulleys to achieve the torque and speed you need.

Justin, that web site is new to me. I wish they had a better layout and more information. It seemed hard to find info. I've never worked with wood, and in my spindle searches I've tended to ignore spindles whose primary application is wood. But when working with small carbide cutters, speeds need to be high. I wish the speed range was more along the lines of 2,000 to 14000 or so. Sometimes you need to go even much slower than 2000, and I'd worry about torque. It's a lot of spindle, but it would hurt to shell out that much money and not have it do what you'd like.

Box spindles from Setco and Gilman, in ISO tapers, have always appealed to me, but even the CAT30 spindles are BIG for a modest bench mill. Why can't someone make an ISO 20 or even 10 box spindle with high quality bearings, suitable for 1 HP or so? I guess the market isn't there.

I've been flogging the small spindle problem for a couple of years now, and am no closer to an answer I'm happy with. For $1900, you may want to look for a surplus HF spindle which may be more suitable for metal work, like a Hofer, maybe a Precise. The latter seem to be pretty common on ebay.

Maybe Setco?
http://www.setcousa.com/index.cfm?fu...09&PATRIARCH=3

This is a very high-quality small spindle which would be nice on a mini-tech sized mill.

The next step is a CAT30 spindle from Setco,

http://www.setcousa.com/index.cfm?fu...6&PATRIARCH=3#

Big jump between these two, and nothing inbetween. Darnit.