milling machine spindle

[kd0afk]

I want to build a milling spindle for my lathe and I have been looking at designs. I found one and I was wondering if it will work.
I don't have the space or the money for a mill so It will be a lathe attachment.
I have a couple questions though; what is meant by preloading the bearings and what is the proper way to do that? And I've read that the bearings need to be opposed. Will a set of tapered bearings be ok?
Will this design work?

 

[dalem9]

HI KD Pre loading the bearings is how much you would turn the nut after all play is removed from the shaft . Say 1/3 turn or 1/8 turn after end play is gone . Yes taper bearing would work . To save space and money I would use an R8 spindel .Unless you have other reason for doing so . Hope this helpes .Dale

 

[velocette]

Hi
This looks like it is the "cats pyjamas" for a milling spindle.
The back to back Angular contact bearings make for smooth running spindle.
How ever they need to be reversed and a spacer on the inner races.
You can then "Preload" them with the end cap spigot made slightly longer.
The end cap is tightened up snug and even all round and then measure the gap between the cap and the housing at three places and take the average.
Fabricate suitable shims- spacers to fit and adjust the shim thickness to give the correct preload.
It is fiddly operation to get it right so patience is required.

Eric

 

[kd0afk]

HI KD Pre loading the bearings is how much you would turn the nut after all play is removed from the shaft . Say 1/3 turn or 1/8 turn after end play is gone . Yes taper bearing would work . To save space and money I would use an R8 spindel .Unless you have other reason for doing so . Hope this helpes .Dale

Are you talking about the draw nut for the collet?

 

[kd0afk]

I want to say that this is not my design. I found it on an image search but couldn't find more info on it.

 

[kd0afk]

Hi
This looks like it is the "cats pyjamas" for a milling spindle.
The back to back Angular contact bearings make for smooth running spindle.
How ever they need to be reversed and a spacer on the inner races.
You can then "Preload" them with the end cap with the spigot made slightly longer.
The end cap is tightened up snug and even all round and then measure the gap between the cap and the housing at three places and take the average.
Fabricate suitable shims- spacers to fit and adjust the shim thickness to give the correct preload.
It is fiddly operation to get it right so patience is required.

Eric

What spigot are you talking about?

 

[velocette]

What spigot are you talking about?

Hi
the spigot is on the end cap were it holds the outer bearing race snug in the housing
A small step that locates the cap concentric with the housing

Eric

 

[kd0afk]

What would be an appropriate steel to use for this?

 

[dalem9]

No this would be the spindle nut . Dale

 

[enfieldbullet]

you can use 1045 for the spindle.needs to be ground and polished on the bearing fits.

angular contact ball bearings will be more expensive than conical roller bearings and more difficult to find.

however, we need to decide on the acceptable TIR(total indicated runout), regular bearings have quite some runout, for taper roller about 40um(just under 2 thou) if i remember correctly. if that's too much you need higher precision bearings.

making machine spindles is somewhat of a big undertaking. everything that comes from it can only be as precise as the spindle and it's bearings are. if you want a machine for hogging off material you'll certainly make something useful. but getting it to shave a few tenths may demand more involvement.

 

[Swifty]

The spindle drawing that you have is for a CNC machine, it's evident by the cutter arbor that's in the spindle, it also has a pull back stud on it for retention.

Although the basic design of the spindle will be the same for a manual machine.

Paul

 

[mu38&Bg#]

This is the one I built. The bearings in that diagram are correct. A matched pair of P4 spindle bearing don't need anything additional for preload.

Greg

 

[Wizard69]

I want to build a milling spindle for my lathe and I have been looking at designs. I found one and I was wondering if it will work. I don't have the space or the money for a mill so It will be a lathe attachment. I have a couple questions though; what is meant by preloading the bearings and what is the proper way to do that? And I've read that the bearings need to be opposed. Will a set of tapered bearings be ok? Will this design work?

There is a lot of design information on the bearing manufactures web sites. I highly recommend spending some time on those sites downloading information.

Before anybody can answer how do you intend to use this spindle? I have to ask because you have a picture of a very large spindle. If you are looking for a spindle to mount on the cross slide I'm afraid you have to take a different approach. Probably the best approach in this case would be to build an ER type spindle. With an ER spindle you should end up with decent capacity without blowing the rest of the spindle up size wise.

As for the bearing I'd suggest looking at the bearing manufactures web sites for example of light duty solutions. Unless you have a plane for something more substantial that a cross slide mounted spindle I don't see any reason to go overboard with the spindle design. A set of angular contact bearings ought to do the trick. As far as bearing type I'd probably go with angular contact ball bearings or possibly what ever is cheapest and gives the required performance.

As far as this specific designed have to say no, it won't work. I could qualify that a bit but it is probably better to just go looking for something else. The interesting thing here is that I think one of the model engineering magazines covered the build of a spindle for use on a lathe not too long ago. I think it was one of the British magazines.

 

[kd0afk]

Basically I would like to cut grooves and slots while the work is on the lathe. Light duty stuff. Some examples would be; making a crotch center or machining the dovetails for a ball turning attachment or finger grooves on a collet chuck nut.

 

[grg12]

I will recommend a book: "Spindles" Harprit Sandhu, available fir example here: http://www.arceurotrade.co.uk/Catalogue/Books.

 

[Cogsy]

Just for reference, you can purchase matched sets of very high precision angular contact bearings, complete with matching spacer (or shim) for the desired preload. Adding preload to a bearing can substantially reduce it's life though (although a very slight amount does increase life a little, but it's technical). These sets are designed for lathe spindles and I used to supply them to engineering firms all the time. They are very expensive though.

If you go for tapered roller bearings, make sure to spin the bearings as you adust them and measure end float. If you don't, you'll end up with 20-40 thou more end float than you thought when the bearings are running.

 

[DICKEYBIRD]

Hey kd, I'm accumulating stuff to add a stepper controlled 3rd milling axis to my ORAC CNC lathe. I recommend looking for a used Sherline 5000 spindle. All those hi-tech bearings & spindles won't be necessary for what you & I are wanting to do.

I searched ebay this morning for one to show you what I'm talking about and ended up buying one for myself as an early birthday present for $82.00. SWMBO will be happy to know she's off the hook now!

Anyway, they don't have fancy bearings & all but they work very well for light milling at up to 10000 rpm. They are compact, mount easily and have a 3/4-16 spindle nose & MT1 taper. I picked up a $15.00 MT1/ER16 collet chuck from CTC tools (+ high shipping from Taiwan) for my Sherline mill. I made a simple drawbar for it and once installed never took it off. ER16 will hold everything you want up to 3/8".

Just a thought that might save you a lot of hassles.;D

Milton

 

[mu38&Bg#]

Milton's suggestion is an excellent one for the use it will see. My spindle went on a CNC mill I use quite often and is capable of much more than you need. If I could have bought exactly what I wanted, I wouldn't have built it as it was a lot of work and not cheap. A simple spindle could be build using common preloaded bearings like the Sherline, but for the money just buy one. There is an er-16 version listed on ebay ending in a couple days. I have no idea what that might be worth.

 

[kd0afk]

Yeah, I meant to post yesterday that I found a sherline lathe/mill head on eBay and that probably the route I'll take. I also saw these AC engraving motors. I'm trying to find out more info on them but that might be an option as well. But, yeah the sherline is what I'm looking for.

 

[petertha]

I recommend looking for a used Sherline 5000 spindle. Milton

Do you mean harvesting the chunk off the mill (attached pic)? That looks like something dead useful mounted on a larger lathe.

I found this link on parts/bearings, but not sure how current the model is.
http://metaltronics.wordpress.com/2010/01/26/replacing-sherline-spindle-bearings/

Not quite sure what this is about, but throwing in the pot FYI
http://www.kickstarter.com/projects/19659206/affordable-sherline-atc-spindle-head