5C "spinde" bearing advice requested

Zahnrad Kopf · May 10, 2013

I have an idea for a tool that might be helpful for me in the shop. It is basically a 5C spindle. The "catch" here is that I need it to be as compact as possible, and have as little runout as is practical. I am looking for a donor tool to start from/with to prove my concept at first, but am having very little luck finding something inexpensive to test the theory with.

I can make up a 5C spindle easily enough, but I have no idea what to do about bearings. Can someone give me an idea of a decent inexpensive bearing arrangement that I can test the theory with? If it works for me, I would purchase and use more expensive bearings if there was an acceptable gain, but for testing I want to keep the costs low.

I'm thinking the spindle tube would be about 4" long, total. Also, it needs to be sealed from corrosives, so seals would be good too.

Thanks.

Heavey Metal · May 10, 2013

When you put the compact and sealed requirement on this you would have to alter this(donor spindle) any way why not build from scratch?

Few questions: What closer, what speed,what is the corrosive material that needs sealed, define your runout requirements, how will it be driven, what is the expected rad & axial load, # cycles per hour/shift/ expected.

Zahnrad Kopf · May 10, 2013

Heavey Metal said:
When you put the compact and sealed requirement on this you would have to alter this(donor spindle) any way why not build from scratch?

Two reasons -
Because if I can find something suitable for testing it will save manufacture time for me.
And...
If I can find something suitable ( using the spindle ) I can make the block it will reside in and install seals.

Heavey Metal said:
Few questions: What closer, what speed,what is the corrosive material that needs sealed, define your runout requirements, how will it be driven, what is the expected rad & axial load, # cycles per hour/shift/ expected.

Simple nut closer to allow through usage.
Corrosive environment, not material. I will likely make the permanent article from Stainless materials.
It would be driven by a small DC motor and there will be no radial or axial load, save for its own weight and friction.

To be honest - think Harig Spindexer. ( motorized version ) LIKE THIS
The difference being that I want to do something more compact and for a specific, dedicated purpose with a much lower profile, and in stainless.

I am willing to make everything if I have to, but for the test prototype I want to test the theory before dumping a bunch of time and money into one.

Heavey Metal · May 10, 2013

Air bearing

stephen thomas · May 10, 2013

Airbearing would be cool!

If you use conventional antifriction bearings my only comment would be don't copy the Harig design (one, deep row radial ball bearing, albeit "rebuildable"). Think closer to the Suburban design with 2 bearings. Master-Grind INDEX FIXTURE & ACCESSORIES by Suburban Tool, Inc.

Edited: Looks like I may be wrong on the spin-dexer you linked to - they refer to "...large preloaded ball bearings.." = bearings plural. Many of their other products such as the Ultra-grind, Grin-all, & Uni-dex products are all single race design.

smt

Zahnrad Kopf · May 10, 2013

I would like to stick with conventional antifriction bearings for the moment. I am not familiar with the bearing arrangement in the Suburbans and did not see an exploded view there. Can you tell me what's inside? Would this be as simple as just getting two tapered roller bearings opposing each other? I've worked with bearings all of my life but sadly know very little about what to use for my purpose on this. Hence, my seeking help here. Thanks.

stephen thomas · May 10, 2013

My original point was not to favor tapered roller vs ball, but to favor 2 bearings vs a single deep row as Harig uses. My understanding is that the Harig's single bearing designs can be somewhat sensitive, and they do eventually lose preload. While they can be rebuilt, I'd prefer the more robust design of 2 bearings. But I also corrected my misapprehension about the (apparently mulitple bearing) Harig spin-dexer, compared to their other products with the single bearing.

I suppose they favor the deep single row for the most precise units to avoid (for lack of a technical term) the possibility of some potential hula motion from 2 bearings. But if the risk is more deflection and faster wear (for a single), I'll go with proven-everywhere multiple bearing spindle design. Hardinge, for instance, used to claim 25 millionths for their lathe spindles.

Not being an engineer I don't know enough to actually specify, though I am confident in my abilities to research and calculate if necessary for my own purposes.

Good luck with it, seems like an interesting project!

smt

gbent · May 10, 2013

Forum member RJ Newbould uses an air purge to keep the bearing dry on his 5C spindles. They just use felt seals but are suitable for submerged usage in an edm tank. Newbould also uses a single row deep groove bearing.

As far as the design of the bearing think two circular vee grooves, one facing in and the other facing out. The inner vee groove is a two piece unit to allow assembly of the bearing. The groove is stacked solid with balls, no separator is used. This is a very compact design axially, but gets its rigidity from the diameter of the bearing.

CalG · May 10, 2013

Have you ruled out a plain bearing for any reason?

A spindexer provides for all the features you have requested thus far, except sealing.
I doubt you could wear one out while testing your concept.

Inexpensive enough just to cut up as desired.

I may have missed some important reason why you might require additional moving parts.

Cheers

Zahnrad Kopf · May 10, 2013

gbent said:
Forum member RJ Newbould uses an air purge to keep the bearing dry on his 5C spindles. They just use felt seals but are suitable for submerged usage in an edm tank. Newbould also uses a single row deep groove bearing. As far as the design of the bearing think two circular vee grooves, one facing in and the other facing out. The inner vee groove is a two piece unit to allow assembly of the bearing. The groove is stacked solid with balls, no separator is used. This is a very compact design axially, but gets its rigidity from the diameter of the bearing.

I actually wrote RJ right off the bat, a week or so ago. Unfortunately, I think I did not properly convey what I was trying to accomplish and it occurred to me that it could be possible to read what I was writing as trying to steal his design or possibly looking for freebies from him, so I dropped the matter.

Regarding your Vee groove explanation, I'm not "getting" it... Can you explain more or show a picture? Thanks.

CalG said:
Have you ruled out a plain bearing for any reason? A spindexer provides for all the features you have requested thus far, except sealing.
I doubt you could wear one out while testing your concept. Inexpensive enough just to cut up as desired. I may have missed some important reason why you might require additional moving parts. Cheers

Funny you should mention that... I was just ( literally ) speaking with a colleague and friend who suggested the very same. I had thought of it, earlier, but would like to get just a little bit more stability/accuracy out of "the widget". The problem is that those things have just a wee bit too much radial play and a lot of axial play. This might play havoc with my experiment. Then again, it might not. I very well might rig a motor up to one that I have and try it, but would like to get my head wrapped around the bearing issue anyway, for when I do set about to building one.

Thanks.

CalG · May 10, 2013

Plain bearing spindles have overcome those play issues for generations. It may take more attention than the $35 Chicom units provide. ;-)

But a proper thrust bearing is a very compact unit, and plating can give as close a fit as can still be free too move in a refined bore.

Can you tell, I'm partial to lightly loaded steel on C.I. I just like the way it feels ;-)

For "ideas" regarding antifriction bearings in a small volume, look to bicycle methods. Tried and true, but only to a certain level of precision.

Zahnrad Kopf · May 10, 2013

Likely I will hack up the spindexer I have on hand to test my theory and curiosity.

gbent · May 10, 2013

Zahnrad Kopf said:
Regarding your Vee groove explanation, I'm not "getting" it... Can you explain more or show a picture? Thanks.

No pictures. They were a lot more difficult back then.

As far as an explanation: Start with a 3" bore. Put a 90 degree vee groove in the bore such that when filled with 1/4" balls the diameter of the centerlines of the balls is about 2.990. This is the outer race. For the inner race you have a spindle that is 2.000 in diameter, and has a larger diameter of 2.980. The exterior corner, from the shoulder to the large diameter, is a 45 degree angle. This angle forms one half of the inner race. The other half of the inner race is a loose piece that pilots (with a slight interference) on the 2.000 diameter. It has a chamfer that matches the one on the spindle. The loose piece is bolted solid to the shoulder on the spindle forming a vee groove on the OD of the spindle.

The assembly of the bearing is very dependent on the size of the chamfers. The bearing is tightened by grinding the mounting face of the loose piece. It is loosened by either using smaller balls or grinding the chamfer larger. The concentricity of the chamfers of the spindle and loose piece is very important.

My hats off to Mr. Newbould as a most excellent grinder hand as well as inventor.

Zahnrad Kopf · May 10, 2013

Very nice. Now I get it. Thank you.
If this proves to work as I hope it does, I will look for a suitable existing product to modify to suit. ( basically just adding the pulley and motor ) RJ's is on the short list of places to inquire with.

oldbikerdude37 · May 10, 2013

Zahnrad Kopf said:
Likely I will hack up the spindexer I have on hand to test my theory and curiosity.

hell yea,you can get a cheapo for under $100 and do what you want and not break the bank.

Zahnrad Kopf · May 10, 2013

oldbikerdude37 said:
hell yea,you can get a cheapo for under $100 and do what you want and not break the bank.

Part of my problem is my resistance to spending ANY of my money on items from places like horror freight. I just refuse. I would sooner turn my own spindle. I do understand that something like this would be the perfect reason to purchase such a thing from such a place, but I just can't. Some times this position of mine causes me grief by delaying things or making them more expensive than they might need to be. Still, it is a personal value that I absolutely refuse to compromise on. That said, I do have one of the less expensive spindexers in the shop that I have had since the late Eighties. I have no idea where it came from as it was in a box of tooling that came with a machine I had bought. I'd be absolutely shocked if it was domestically made, but it is still much better quality than the typical horror freight types of examples.

CalG · May 10, 2013

Zahnrad Kopf said:
Part of my problem is my resistance to spending ANY of my money on items from places like horror freight. I just refuse. I would sooner turn my own spindle. I do understand that something like this would be the perfect reason to purchase such a thing from such a place, but I just can't. Some times this position of mine causes me grief by delaying things or making them more expensive than they might need to be. Still, it is a personal value that I absolutely refuse to compromise on. That said, I do have one of the less expensive spindexers in the shop that I have had since the late Eighties. I have no idea where it came from as it was in a box of tooling that came with a machine I had bought. I'd be absolutely shocked if it was domestically made, but it is still much better quality than the typical horror freight types of examples.

I share your determination to NOT PURCHASE JUNK. Just don't do it ;-)

strokersix · May 10, 2013

Agree with the sentiment not to purchase junk. However, I got a green one for about $35 I think. Pleasantly surprised with it's performance. Sure beats cutting up a good one to test your concept.

oldbikerdude37 · May 10, 2013

Zahnrad Kopf said:
Part of my problem is my resistance to spending ANY of my money on items from places like horror freight. I just refuse. I would sooner turn my own spindle. I do understand that something like this would be the perfect reason to purchase such a thing from such a place, but I just can't. Some times this position of mine causes me grief by delaying things or making them more expensive than they might need to be. Still, it is a personal value that I absolutely refuse to compromise on. That said, I do have one of the less expensive spindexers in the shop that I have had since the late Eighties. I have no idea where it came from as it was in a box of tooling that came with a machine I had bought. I'd be absolutely shocked if it was domestically made, but it is still much better quality than the typical horror freight types of examples.

the beauty of buying the cheap shit is you can hack,saw, weld, mount fixtures or anything you want to it and only make it better. You could spend 10 X more and get one that holds .0000050" and still have to machine it,but its your money.

I like to buy the cheap wrenches so I can cut them up or weld on them and never think twice about the cost.

Building it would take less time then talking about it. Hope you make it and post pictures and show off your work. I would like to see it.
Iv been wanting to build a tracer copy router jig that's a similar idea.

Heavey Metal · May 10, 2013

I think rj has an indexer with a motor on it for sale.

Some times when you are busy it is cheaper to buy something ready to go rather than reinventing the wheel.

5C "spinde" bearing advice requested

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