Help with spacer sleeves

[RSG]

Hey guys,

Most of you know I make fishing reels and this is the time of year were I am at the assembly stage. Part of that involves producing spacer sleeves to set the correct space between the bearings in the journal. This requires a great deal of precision as the difference between the inner and outer sleeve thickness must be .00035" to set the proper preload. So my issue is machining them to this level of tolerance without having to take them to a granite table with fine sandpaper to hone them in.

Pic of the journal below
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The specifications are as follows:
Material - Aluminum
Size (Length) - Outer spacer - .2259"
-Inner spacer - .22555"

Currently I machine the dia and bore, then part off square. Then flip over and machine the other face in soft jaws. When finished they tend to be all over the place as far as dimension goes and the faces aren't parallel. They can be off as much as 3 or 4 tenths from one side to the other.

Is there a better way to do this so I can just part off at the correct measurement without having to keep taking the bearing out to hone the spacers several times for each reel.

Thanks in advance.

[Magicniner]

Currently I machine the dia and bore, then part off square. Then flip over and machine the other face in soft jaws.

I had imagined that the soft jaws, if properly machined and used, and mounted on a quality chuck ought to be getting you very close

[leeko]

Forgive me if I'm missing something, but I'm not sure that getting closer than 3 or 4 tenths is a consistently gettable target on a lathe - that's where grinders come in. What kind of lathe are you using? What condition is it in?

Lee

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[RSG]

Forgive me if I'm missing something, but I'm not sure that getting closer than 3 or 4 tenths is a consistently gettable target on a lathe - that's where grinders come in. What kind of lathe are you using? What condition is it in?

Lee

Sent from my SM-N920T using Tapatalk

I would also agree but I what I think is important to me is getting the faces parallel, and currently I'm not. As for grinding, I didn't think you could use a conventional surface grinder for aluminum. The lathe is a 12x36 King only a few years old.

[RSG]

I had imagined that the soft jaws, if properly machined and used, and mounted on a quality chuck ought to be getting you very close

Ya, I thought the same. My soft jaw chuck and jaws are robust and I am no stranger to fabricating them. My only thought was that the parts are so small there is room for movement when inserting them in the chuck. I get excellent results on larger parts in soft jaws.

[Conrad_R_Hoffman]

I grind aluminum quite often. Obviously it doesn't stick to the magnetic chuck! Depending on surface area and how much needs to be taken off, I bond it to a steel plate (that's been ground parallel) using either double stick tape or a thermal adhesive made for crystal and semiconductor type dicing.
http://www.aquabondtechnologies.com/The ... -Adhesives

Whatever you use, there has to be enough surface area to hold the part reliably, as a tilting cylinder is a recipe for disaster with a grinder. Maybe back it up with a V-block so it can't tilt if it comes free. My 612 grinder is OK, but it's still hard to get better than 0.0002" just due to settability of the dial and mystery temperature and time effects.

WD-40 works well- don't do it dry! I would have though a special wheel was needed, but a open bond white wheel ("sugar wheel") works fine.

[RSG]

Thanks Conrad, if I only had a grinder...LOL

[Magicniner]

Have a play with an arbor, Joe Pieczynski on YouTube has a very good current video on Arbors.

[spro]

How thick are these sleeves ? There is THINBIT tooling which are very thin but sturdy. It comes to what has been said about parting blades. The pressure of a wider cutoff tool upsets the thin items' center.

[RSG]

Have a play with an arbor, Joe Pieczynski on YouTube has a very good current video on Arbors.

Thanks for that Magicniner! It gives me an idea about turning my soft jaws opposite to how I do them now. I might try making them grip on the open instead.

[RSG]

How thick are these sleeves ? There is THINBIT tooling which are very thin but sturdy. It comes to what has been said about parting blades. The pressure of a wider cutoff tool upsets the thin items' center.

Spro, They are fairly thin - .050" wall thickness. Thanks for the recommendation. Looks like make a huge variety of tooling.

[Patio]

I would try using an arbor too. Bore the ID of the sleeve to size. Mount them on an expanding arbor, and you should be able to turn the OD, face both ends of the spacers, and measure them, in one set up.

Just a thought.