[ZipSnipe]

Ok here is a pic of my quill spindle that I am doing for my mill.

question #1 If I use snap rings do I need preload on the outer race of the bearing?

and if I do can I get away with like using the wavy spring washers?

[dmalicky]

With snap rings, it would be very difficult to machine the spacer length, and install the snap rings, so it all fits with the right amount of compression. (Even if successful, when it heats up and expands, the preload is thrown off.)

If there is axial slop between the rings, the R8 spindle would shift up/down when the cutting force changes direction. A wavy spring washer delays some of that, but once the axial force exceeds the spring load, slop occurs (less abruptly, though). The slop may get worse as the snap ring/groove gets hit repeatedly. The design may work if cutting forces are very light.

The standard spindle config uses duplex angular contact bearings at the nose, with the outer races clamped to the spindle casing using a plate or similar. Those 2 bearings take all the axial loads. At the tail, a radial bearing floats axially in the housing, located with spacers like your sketch shows. There are some nice drawings and schematics in the archives. It's tough to improve on that design: stiff, no slop, simple, and ~insenstive to thermal expansion.

[ZipSnipe]

Thanx for the reply David

So maybe can the snap rings and do a bolt on plate would be better?

[handlewanker]

Loosely speaking, yesssss, but it needs to be PROPERLY designed not just a "bolt on plate".

Check out the conventional spindle/quill designs and if you have the machining capability use the design as it is shown.

Spindles will react to bad design in a very predictable manner....LOL.
Ian.

[RICHARD ZASTROW]

Nearly every spindle I've seen that uses a snap ring has the same problem. The bearing pushes against the snap ring; the snap ring beats on the ring groove; the ring groove gets deformed; the bearings get axial play in the housing.

If the bearings are arranged face to face (not the best idea), they will loose preload as well. It only needs to loose a few microns to loose preload.

Dick Z

[ZipSnipe]

I guess what I should mention that this spindle is based on the Mini Mill X2 spindle which is what I have on the mill now. And when I look at an exploded view of the X2 The only place I see on the spindle that would get any preload adjustment is on the inner race with the spindle nut, The outer race is covered with plastic dust cap.

I guess I will just basically mimic the same design as it has served me well for over 6 years and with radial bearings at that

[RICHARD ZASTROW]

I'd like to see that spindle drawing, but I can't open the attachment.

Dick Z

[ZipSnipe]

Sorry I don't know why it won't open for you. I clik on it and it opens fine.

I should also point out that this spindle is going into a quill

[handlewanker]

Hi Zip, just looked at your drawing in post #1, as it opens now for me.

I see you have an angular contact at the bottom and a radial at the top, with snap rings top and bottom.

This is not a conventional build, and although it might work the top bearing is being forced to act like an angular contact bearing, but is not designed to come anywhere near it's capability.

You could just as well have an angular contact bearing in both positions, one at the top and one at the bottom cups facing outwards, although spindle design dictates that thermal expansion will upset the bearing preload if used in this way, but it will be heaps better than having a radial at the top.

Used in the manner I stated, you do not need to have any snap rings as the bearing outer races are being pulled against the shoulder in the housing top and bottom by the nut on the spindle against the top bearing inner race.

The nut does need to be locked once preload is set, usually you will have two nuts locked together, or if the nut is above the level of the housing top you can have it split with an Allen cap screw through the side to lock it tight.

The bottom of the housing then just needs a cover plate with a seal to keep the lube in and the swarf out....the same for the top.

This is not the ideal design, although similar, it's better than the design you show in post #1 with the radial top bearing, and you can adjust the preload as required knowing that the bearings will take it.

If you wanted to go the whole hog, have two angular contacts at the bottom cups facing inwards, and a radial at the top with a long spacer between the angular contact bearing inner races at the bottom and the radial at the top, and the nut locked down on top of the radial bearing inner race....the radial bearing outer race is allowed to float up and down in the housing bore.....a sliding fit.

You will also need a bearing retainer cap in the bottom of the housing to clamp the angular contact bearings against the shoulder in the housing bottom.

This means you need to bore the bearing bores at the bottom deeper to take the two angular contact bearings ( a sliding fit), and the spigot of the retainer cap......the cap MUST clamp the bearing outer races against the shoulder.
Ian.

[RICHARD ZASTROW]

ZipSnipe, What Ian said will work. Also, the locknut you might look at Whittet & Higgins "Bearhug" locknuts. Taper Line Inc. makes locknuts with built in clamping screws to prevent them from backing up or loosening.

Dick Z

[handlewanker]

Hi Dick, I like that method of locking a retainer nut, very positive.....seen too many designs that rank from the screw through the side on a soft copper slug to the slit side version where the circular nut is split through the side of the nut to the thread and a screw on top compresses it against the thread.....OK if you only have access from the top.

The worst ones are the twin lock nuts with slots round the periphery,that always are the pitts to get tight.....many are hit loose or tight with a pin punch, and the other one that has a washer underneath that gets tagged into a hole and has the side bent up to secure the nut.

The spindle design will depend on the machining ability of Zip, but he'll need to have some machining ability to make it work, whatever the design finalises at....it'll make or break the spindle as a useable item.
Ian.

[RICHARD ZASTROW]

Whittet & Higgens sells extended socket wrenches for the slotted locknuts. Kinda pricey but they let you tighten locknuts inside a cavity. They also sell the screw locking types as well. Some tighten on the axial axis others from the radial side.

I don't have any relation to them other than a customer.

Dick Z

[handlewanker]

Hi Rich, wherever possible it's best to avoid having those slotted lock nuts in a cavity where you can't get at them.

By that I mean if the top ball race of a spindle is level with the top of the quill, the nuts will be out in the open on top of the bearing inner race, in which case a number of nut designs can be used.

Personally I like the split nut with the screw through the side clamping method, adjusts easy and clamps up rigid.
Ian.

[RICHARD ZASTROW]

Ian, Right now we're building some spindles. They're inside of housings that require the nuts to be inside of cavities. A real PITA!!! Those socket wrenches work well in there.

Another good nut is the Spieth adjustable locknut from Germany. A bit pricey also, but good stuff as is most German hardware. (can you tell I'm of German heritage?)LOL

Dick Z

[handlewanker]

Ja!.....LOL.....sree munts von der vaderlund out Ja?.......ich bin ein Pom......30 years out from the Motherland.

On the subject of spindle bearing locking, I have a small jig borer, and in the spindle rebuild it was intended to have the two A/C bearings at the bottom secured, cups facing inwards, with a pair of nuts before inserting in the housing, then clamped in the housing by the bearing front retainer cover.......at the top there was going to be a sealed radial bearing secured in the housing against a shoulder and floating on the spindle in the usual way.

Now I want to have the two A/C bearings at the bottom, but with a long spacer between the inner race and the the radial ballrace inner race at the top, and have the retainer nut on the top of the radial ballrace inner race, the bearing floating in the housing.

This will enable the spindle to be locked to all bearings out in the open at the top with just one retainer nut with the split and side lock screw I'm so fond of, mainly because it makes access to the locking method simple.

BTW, how does the Spieth adjustable locknut work?
Ian.

[RICHARD ZASTROW]

Ian, My family comes from the Mecklenburg/West Pomer area, from the booming metropoli of (can you believe it?) Grosser Zastrow and Klein Zastrow.

Back to work. All the Spieth hardware catalogs are on the internet. They have all kinds of clever stuff. We use locknuts and quite a few "clamping sleeves". These are great for securing thngs with I.D.'s to things with O.D.'s like shafts to pulleys etc., no key or keyway required.

Try "googling" Spieth or clamping sleeves or combinations like Spieth Locknuts.

I'm not connected to Spieth only a happy customer.

Latest spindle has two sealed A/C bearings back to back. These are clamped on the inner rings to a shaft shoulder at the working end of the spindle by a locknut directly behind the A/C bearings inner rings. This is held in place by a housing shoulder behind the rear most outer ring and a bearing cap at the front outer ring. Common practice.

The opposite end (powered end) has a floating sealed radial bearing clamped to a reduced spindle shaft dia. by another locknut. This can float in the housing bore with .0002" clearance.

This way, no spacer is required. This is not to say spacers aren't a good practice. Spacers between the front A/C bearings (at least as wide as the bearings width) add rigidity and help in heat dissapation. The spacers, both inner ring & outer ring MUST BE EXACTLY THE SAME LENGTH & PARALLEL. If not, the spacers will cause havoc to the high precision bearings. We keep ours within .00005" (.0013MM). Not for the average DIY'er.

'nuff fer now.

Dick Z

add: www.ame.com/products

[handlewanker]

Hi, Had a look at the Spieth locking nut........I like that design for access from the top, now I have two favourite methods, and it's completely DIY capable, just two thin nuts with a space between them to allow compression on the thread by a couple of screws round the periphery.

I'm trying to work out how the design would work for a plain shaft, or is it only for locking threads etc.

I suppose if you had a pulley you wanted to lock to a shaft, and you had a collar against the pulley boss that had a tapered face, it would lock onto the shaft if the collar was drawn against it with a couple of screws on one side by the deflection of the collar bore......hmmmmm.

The pulley, or anything else, like a gear or retainer collar etc, would have to have a bore diam/length ratio of at least 2:1 to ensure the pulley etc did not deflect as well as the locking collar and cause it to run out.

Thinking about this at great length, which is what I seem to do best these days, the collar being behind the pulley boss, which normally faces inwards on most machinery, could be locked from the outside face of the pulley by the screws going through the pulley outer face....very accessible and simple, but it does increase the pulley boss length.

Even using the taperlock pulley retainer system, I have found that when the locking screws are tightened, although the tapered split bush does go tight on the shaft, the pulley itself can have a bit of run out (face wobble) if the screws are not tightened very carefully and progressively, and some loosening and retightening is required for a perfect alignment......dial indicator for perfectionists.....LOL.
Ian.

[RICHARD ZASTROW]

Ian, I hope ZipSnipe is getting some good info from our discourse on his thread.

For securing pulleys to shafts etc. we use the clamping sleeves, not locknuts. Check out the clamping sleeves catalog. Since it clamps to shafts without the need for keys/keyways, you can adjust the part you are clamping axially and radially for timing.

I bet you could find a use for the adjustable gibs as well.LOL

Dick Z

[handlewanker]

"ee's gone very quiet, maybe the original design was already in the making....oh well, advice given is dirt cheap.
Ian.

[ZipSnipe]

Gentlemen excuse me for not replying back. I actually lost this thread.

Anyway, I will not be using snap rings, The locknut I have has a set screw to help lock it down. The top bearing is a radial bearing but its the same bearing that is used in the x2 so I should be fine.

I do appreciate your feed back, thanx again !!!!