steverboss,
Welcome to the Shopsmith Forum.
You asked the following questions,
What are pros & cons of the 555608 vs the 555321 arbors?
There use is based on which Table System your Mark has.
Why are there 2 different arbors?
When the Mark V 510 & 505 were introduced the Lower Blade Guard design had a deeper throat. This required longer Arbors for its use. That Lower Blade Guard is the same one used with the Mark V 520, Mark 7 and Mark 4. Originally an Arbor part number 555118 was used for the Mark V 510/505 and looked like a longer 555321 Arbor. The 555118 was later replaced by the Arbor 555608 which had been in use for the SawSmith Table Saw. The 555118 Arbor has the same spacing as the 555608 Arbor
When will each not work properly?
The 5/8" Arbor part number 555321 cannot be used on the Mark V 505, 510, 520, Mark 7 and Mark 4. It is too short. Arbor 555608 being longer may not work in all Mark 5/V 500 Lower Blade Guards. The carriage also has to be further away from the Headstock to center the blade when using the 555608 Arbor on a Mark 5/V 500 Table system.
Or are they interchangeable.
Yes and no. Depending on the Lower Blade Guard in use on a Mark V 500 or original Table System Mark 5/V the longer Arbor 555608 could be used. The Arbor 555321 cannot be used on the Mark V 505, 510, 520, Mark 7 and Mark 4 as noted above. The Arbors 555118 and 555608 are interchangeable for the Mark V 505, 510, 520, Mark 7 and Mark 4.
Below is a picture of the Arbors 555321 and 555608.
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- 555321 555608 labeled.jpg (169.65 KiB) Viewed 1135 times
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Lastly, JPG gave good advice. ALWAYS check the prices for parts here on the Shopsmith website. Quite often prices for items on ebay are higher especially when you consider their often-higher shipping costs. Plus, it is new vs used. Just because someone calls it "vintage" on ebay, parts may very well be the same as current new parts from the factory.