The planets are in alignment

[DonInReno]

My darling significant other bought a nice little Wittenstein 75 series 7:1 planetary gear reduction unit as a birthday present!  To be honest I have no idea if this will somehow work in place of big pulleys and extra belts let alone be a better solution, but it's cool and in my hands so we're gonna try!

Nothing in any google searches comes up regarding planetary reduction and sewing machines of any kind, but doesn't it seem reasonable that something like this could make a cleaner way to slow things down?  If anyone's gone down this road it would be interesting to see what worked and what didn't.

Rather than start with a marginal reduction and have to use a really small drive pulley, 7:1 can be sped up easily or kept super slow.  This unit has .866" (22mm) input and output, with the input sleeved to .754" or so.  A different sleeve will need to be whipped up fitting a servo motor and some kind of plate to mate the motor securely.

How noisy are these? The other potential downside is how significant the extra rotational friction is and how it affects manually using the hand wheel. This might be the downfall of the unit since the rubber seals have quite a good grab on the shafts, but it can be spun backwards with about the force it takes to turn over a Juki LU-562 type of machine.

 

 

 

 

 

[Gregg From Keystone Sewing]

Obviously only one way to find out...report back please!

[DonInReno]

Finally a relaxing weekend to play with the reducer!  Since it's usually best to start with easy stuff.  The factory spacer was removed and a little duct tape became a temporary coupling to make sure the initial motor torque could overcome the grip the oil seals have on the input and output shafts - at least with no additional resistance the motor didn't seem to notice the reducer was attached.

Another potential problem was an additional source of noise.  However, these reducers are nearly silent - or at least the motor hum drowned out any sound the planetaries may have made.

The cool part is right off the reducer on the lowest 200 to 500 RPM speed range it's roughly 30 to 70 RPM so even directly coupled to the head 1:1 it's a nice slow granny-gear range, albeit maybe a little too slow.  At 3000 motor RPM's the reducer puts out 410 RPM's - (edit - this is about the speed I like to sew most things at).

The higher the reduction the harder the hand wheel on the sewing machine will be to turn so my gut feeling is the reducer needs a slightly larger pulley than the machine for that reason as well.  

Edited April 14, 2018 by DonInReno

[DonInReno]

A scrap of 1/4" aluminum large enough to mount to the motor that will in turn attach to the factory spacer on the reducer was a whopping $ .40 and a bronze sleeve that will be bored out and pressed on the motor shaft was another $3.

This motor is not in any way bullet proof! Just looking at the thing cracked the fan shroud and the front cover that supports the input bearing is not confidence inspiring - definitely too thin to mount the spacer to, so the four screws holding the bearing retainer in place will also be the attachment points for the 1/4" aluminum plate.  The bearing retainer bore must be cast .003" -.004" larger than the input bearing - at the slightest bearing roughness this is sure to be the end of the motor as the outer bearing race eats and wobbles out the retainer - hopefully it squeals a warning before spinning the bearing.  Having said that there's no reason this motor can't run indefinitely as long as it's not overheated damaging the coils and the sealed ball bearings are replaced at the slightest sign of roughness.  There are no brushes or other moving parts.  

[DonInReno]

To make sense out of these reducers there is a lot of documentation in the 454 page catalog!  Basically I picked up a rather ordinary middle of the road model.

[480volt]

How about a little Loctite red on the bearing when you assemble it to encourage it to stay put?

[DonInReno]

Yes, I think some kind of extra hold on the bearings is a good idea.  I'd like to still be able to pull the covers without having to heat them up to release something like loctite so....IDK.  I'll probably peen the aluminum to close up the bearing recess a little to a stiff slip fit and not worry about it.

 

As for the reducer I picked up, the next one will be a smaller size - the o75 size is rated for about 50 ft-lbs of output torque - much more than required.  The ratios available are 1:3 to 1:100 and 1:5 is probably a better choice as well! Lol

There are literally hundreds of variants of this reducer - many of which would be hard to retrofit, so it's pretty important to at least see the input and output.  

[DonInReno]

The reducer is finally installed, but not in the way originally intended.  Direct connection of the motor shaft to the input of the reducer seemed like a great idea, but it turns into a long awkward looking contraption.

With the Consew CSM1000 the 111w155 with factory hand wheel will sew one stitch per second up to about 30 stitches per second - the speed range I was aiming for.   The biggest downside to this arrangement is the force required to turn the hand wheel by hand - it would be much better to use a bigger hand wheel and bigger output pulley to reduce the reduction a bit.

I wouldn't get another planetary reducer unless a servo with NEMA mounting arrangement could be used to cleanly directly mount the two.  Compared to the typical 3:1 pulley reducer it is more compact, and different, but better I'm not so sure yet. :-)

[DonInReno]

Rather than shifting machines with different bed lengths to the rear of the bed cutout to line up with the speed reducer, I want to easily slide the motor/reducer to where a machine is.  It’s a tall order to use one table for a sailrite clone to a double needle upholstery machine, to a center mounted cylinder arm, to an edge of table mount! Lol   

The 7:1 reducer was just way too slow and 3:1 is popular for a reason.  This little guy is 3:1 and was removed from decommissioned equipment. About $500 new - for $100 I don’t mind if it has .001” extra backlash, but so far it feels nice and tight.  

 

[dikman]

An interesting project, I look forward to seeing how it turns out.

[DonInReno]

Thanks - it’s just a goofy fun project to give me something to do over the Christmas vacation :-)

[DonInReno]

Finally had time to dig into the new reducer and so far it seems much more compatible for sewing.  It’s a 050 size, which is two steps down from the first one that I’ve been using this year.  It’s super compact and eliminates one belt that would be used in a traditional reducer.  It’s so compact in fact there’s a good chance at least one of my fabric machines will get directly coupled and eliminate all the v belts, although in that case a 5:1 reducer might be better matched.

I was happily surprised to find it came with a flex coupling.  So the input shaft is 14mm, the output is 16mm and both ends of the flex coupling are 14mm.   

A 5/8” pulley was drilled out to 16mm with a countersink bit that was .005” under 16mm then finished up with a router bit that just by chance was exactly 16mm across the cutters.  Honestly I didn’t expect the router bit to survive, but with lots of oil and a very slow feed rate it appears none the worse for wear.

Drilling out one side of the flex coupling didn’t go as well since I tried to save a half hour and clamped it in the vice with a bored out piece of wood that was just too soft and it moved a bit over .008” which is too much runout for this type of coupler.  We’re a little spoiled with a Grainger store about 5 minutes away - a new coupler already the correct dimensions is only about $10.

For a motor that little consew servo will mount up very easy - if the front bearing retainer plate is just too thin and it craps out I won’t miss it much.   To join the motor the threads are cut off the motor shaft, four mounting holes are drilled in the front case and it bolts together in a nice compact package.

The world is so full of metric parts I almost ordered a set of drill bits, but instead wasted a couple of hours that would have paid for the new drill bits - it’s silly what we do to avoid having to wait two days for shipping...it still makes me chuckle.

 

 

[DonInReno]

I almost forgot to mention how much I’ve grown to like the first reducer.  I’ve sewn with it about 8 months and the biggest change is I rarely have to touch the hand wheel.  Literally the handwheel may not get touched in any given sewing session.  With a quick tap on the gas I’m able to inch it along 1/8 of a stitch at a time.  Stopping the needle all the way up or down is a piece of cake so a needle positioner wouldn’t do me much good.

Between the motor and reducer the pulleys are set up to function more like a 5:1 and the initial stiffness I was worried about has not been an issue and it’s not difficult to hand wheel if need be.  Having a little too much reduction makes sewing much more relaxing and I’ll not miss the days of always being on edge with a machine that hauls asss! Lol

[dikman]

Haven't got a lathe? You definitely sound like you need one! As for using a router bit to ream out the hole - (but I guess as long as it worked).

These days if you do any metal work you really need a set of metric drills, taps and dies unfortunately. Even then you can still run into lesser used pitches that you don't have a tap for!

[DonInReno]

It’s funny that you mention a lathe - being primarily a wood guy my side of the family garage is filled with woodworking tools, but for a month now I’ve been adjusting to the idea of replacing a mobile wood lathe for turning tapered columns with a big stationary metal lathe.  Here’s a cute little bar in a train caboose that I finished earlier this year.

[dikman]

Now that looks very classy!

If you're going to tinker with making things in metal (as you have been) then even a medium sized lathe will be invaluable. A small mill is also very useful, but a milling attachment can be used on a lathe. I just bought one of those little lathes on ebay and it's quite useful for turning small items (the bigger lathe can be clumsy for small pins etc.) but it did need a bit of work to get it usable.

[immiketoo]

Wow.  The level of cool here is off the charts.  I love this experiment.

[CowboyBob]

That is some really nice looking work you've done there.

[alpha2]

Nice caboose! (And I don't say that to all the guys!)

Maybe I don't hang out in enough bars, but what is the thing circled?

Jeff

[DonInReno]

On 12/27/2018 at 6:39 AM, alpha2 said:

Nice caboose! (And I don't say that to all the guys!)

Maybe I don't hang out in enough bars, but what is the thing circled?

Jeff

Wow - this is an old post - sorry Jeff I somehow missed your question!  :-)

For months the client and I were on the lookout for an old looking faucet for the bar sink, then one day he showed up grinning from ear to ear saying he found a good one!   This is a $4k faucet, but it’s not available in brass, so he sent it to a plater and had it brass plated and with a clear coating of some kind - probably another $1k?  It was nice to have such a good budget on that project!

The caboose is a “yard bar” and when large parties are thrown a bartender is hired to pour drinks and the bathroom is fully functional.

 

[1hp]

thanks to @DonInReno for shoving me down this rabbit hole. it is a 4:1 by Micron.

[Quade]

What kind of servo is that? 

[1hp]

it is the original consew cs1000 that came with my 206rb5 like 10 years ago. had to do the optical mod on it.

[Quade]

Thanks. That seems so much beefier than what Consew is selling today.