5/8 Arbor Length?

[paulrussell]

I am sifting through an accumulation of Shopsmith parts and noted I have a huge collection of arbors, including two 5/8 arbors. These have a short screw shaft and appear to be for the mounting of a single blade -- not a dados/shapers or "universal" arbor.

In the attached photo, the arbors are (from left to right)
Old 500 arbor
Newer 500 arbor
5/8 arbor in question
510/520 arbor
5/8 "Universal" arbor

The thing I don't understand is the length of the middle 5/8" arbor -- it mounts the blade further from the headstock than a 500 arbor, but closer than a 510/520 arbor.

Why is this?

(When mounted on the Shopsmith, the 5/8 arbor aligns the blade on the arbor to the left, the 500/510/520 align the blade to the right.)

[tomsalwasser]

Not sure Paul but I have a question for you. Are the set screws all at a 3 degree angle?

[paulrussell]

Not sure Paul but I have a question for you. Are the set screws all at a 3 degree angle?

I cannot say if they are exactly 3 degrees, but all set screws are canted slightly with head of screw closer to headstock than mating end.

[JPG]

Methinks either a 'goof' or intentionally(&^%W$%#E#$^%) made to not self align 'foreign' blades. Then again, maybe self aligning not considered at all for the 5/8" arbor.

Now why is the longer(505-520) arbor aligning to the right?(on a 505-520 'shopsmith' I assume) Short/collapsed rubber spacer?

[paulrussell]

Methinks either a 'goof' or intentionally(&^%W$%#E#$^%) made to not self align 'foreign' blades. Then again, maybe self aligning not considered at all for the 5/8" arbor.

If it is a goof, I've got several with the same mistake.

Now why is the longer(505-520) arbor aligning to the right?(on a 505-520 'shopsmith' I assume) Short/collapsed rubber spacer?

I think I said something somewhat ambiguous:

By "aligning to the right" I mean that when mounted on the SS the fixed mating shoulder on Shopsmith 1.25" arbors is to the right, the nut to the left, thus aligning right.

The 5/8" arbors (universal and the one in question) have the fixed shoulder to the left, and the nut to the right -- thus aligning left.

[JPG]

Methinks either a 'goof' or intentionally(&^%W$%#E#$^%) made to not self align 'foreign' blades. Then again, maybe self aligning not considered at all for the 5/8" arbor.

If it is a goof, I've got several with the same mistake.

Now why is the longer(505-520) arbor aligning to the right?(on a 505-520 'shopsmith' I assume) Short/collapsed rubber spacer?

I think I said something somewhat ambiguous:

By "aligning to the right" I mean that when mounted on the SS the fixed mating shoulder on Shopsmith 1.25" arbors is to the right, the nut to the left, thus aligning right.

The 5/8" arbors (universal and the one in question) have the fixed shoulder to the left, and the nut to the right -- thus aligning left.

Ahhh left/right = interior /exterior shoulder, NOT blade slot.

[jsburger]

Methinks either a 'goof' or intentionally(&^%W$%#E#$^%) made to not self align 'foreign' blades. Then again, maybe self aligning not considered at all for the 5/8" arbor.

If it is a goof, I've got several with the same mistake.

Now why is the longer(505-520) arbor aligning to the right?(on a 505-520 'shopsmith' I assume) Short/collapsed rubber spacer?

I think I said something somewhat ambiguous:

By "aligning to the right" I mean that when mounted on the SS the fixed mating shoulder on Shopsmith 1.25" arbors is to the right, the nut to the left, thus aligning right.

The 5/8" arbors (universal and the one in question) have the fixed shoulder to the left, and the nut to the right -- thus aligning left.

As far as the 5/8" arbor, the nut can't be located on the left since it is smaller than the diameter of the body of the arbor and it won't fit over it. The nut on the 1 1/4" arbor is larger than the diameter of the body of the arbor and it will fit over it.

As to why the 1 1/4" arbor is made with the fixed flange the way it is I don't know other than it can be done that way and the 5/8" arbor cannot. Maybe it is a manufacturing consideration. It might be easier/cheaper to machine the part that way rather than have the fixed flange in the middle of the arbor.

[reible]

The other factor that comes into play with arbors are the table saw and radial arm saw that shopsmith use to have. I seem to remember that they had different sizes and perhaps even different thread directions.

The last one on the right has at least two version as well. Some of these things have been posted about here before.

Just got back and found I had not posted this......... well a couple of hours late but still.....

Ed

[JPG]

The reason for the 1 1/4" arbor nut being on the 'inside' is to minimize the extent of the arbor beyond the slot(think trunion interference). Now that incurred the extra cost of having to make it with a left handed thread.

[rpd]

As to why the 1 1/4" arbor is made with the fixed flange the way it is I don't know other than it can be done that way and the 5/8" arbor cannot. Maybe it is a manufacturing consideration. It might be easier/cheaper to machine the part that way rather than have the fixed flange in the middle of the arbor.

Also, with the flange on the outboard side the blade can not escape in the unlikely event that the nut comes loose.