bspisak wrote:Thanks for any insight!
I've been waiting for your question for 6 months. I didn't know how to address this subject, but you have presented a well thought out inquiry. Just the ticket for my expressions.
The 520 is an upgrade many swear by, it undoubtedly is a great tool like the 510. Essentially, the difference between the two are the table rails and the fence. I have often been astonished by reports of the superiority of the 520 over the 510. I often have to think - my 510 does that operation great! I have not yet found (read) a report of something the 520 can do better or easier. That said, the 520 is an upgrade I might buy some year. If I do- it will be because I wanted it - not because I needed it. Let's go to your post and I will comment on your post, - as truthfully as I can, with my not totally unbiased opinion.
Yes, an up-grade to 510 then to 520 will cost more than going directly to a 520.
First the Fence:
*It is wider - yes but what does that get you? Two top "T" slots and a little more beef.
*It allows more fixturing - Really? What kind of fixture requires both of these slots. The 510 fence has one and it works toward either side of the fence.
*Has separate front and rear lock levers - So? The 510 fence locks on both the front and rear also.
*Drops straight on the rails - Yes it does, but why is that an advantage? The 510 fence goes onto the front rail with the rear of the fence raised. This is not a dis-advantage.
Now the rails:
*Uses extruded rails, not tubes - The extruded, angular rail of the 520 are undoubtedly stronger than the chromed tubes of the 510. However the tubes of the 510 are strong and do not bend or stretch. Can't say how much force it would take to bend one.
*The magnetic direct reading scale - Many of the newer woodworking machines have scales Incorporated with their tool. Many woodworkers like it! I wouldn't have much use for it (I think). I prefer
NOT to use measuring tapes and scales. It is my feeling that every time a measurement (little line) from a scale is transferred to wood an error is possible. That's why I prefer sticks and blocks to tapes. Yes, I have to use tapes, but keep it to a minimum. Why would I need one on my SS?
Next - Your Questions]Does the greater fence width provide any advantages other than allowing dual t-slots on the top? Is this fence inherently more stable?
Don't see any advantages with this fence. The 510 fence locks on front and rear. More Stable? The added mass of the fence, probably makes it slightly more stable, however the 510 fence, like the 520, is essentially un-movable when locked down.
[*]What advantage is there to separate locking levers? Seems like more fiddling around. Is the fence not perfectly accurate unless I lock the front and rear in sequence as opposed to with a single lever?
Separate locking front and rear are necessary for stability and no deflection. Both the 510 and the 520 should be locked in sequence. (front first) The difference here is the 510 has a screw operated clamp on front. The 520 has a lever locked clamp.
[*]Do the extruded rails provide greater accuracy?
Probably not. I don't think anyone can show greater accuracy. The tubes of the 510 are very accurate when they are aligned and tightened from the front of the saw table first (before the back). As I've read in this forum, 520 alignment can have its problems, but if installed properly they are very accurate also.
[*]Is there an advantage of the 510 tubular design that you don't get with the 520? I'm thinking the 520 rails look bulkier and might get in the way more. Do the 520 rails interfere any accessories like the support table or extension table brackets (to use the floating tables as out-feed tables?)
I wouldn't be concerned with the 520 rails getting in the way of anything. They work very good with all Shopsmith accessories.
The 510's tubular design of the rails also works perfectly with the extension tubes. The Screw locks of the 510 push the extension tubes out to the front of the tubular rails. If one tightens the front of the saw table first then works outward from there on the front, all floating tables are perfectly aligned for the rip fence.
[*]Looks like the 520 rails have locking knobs for the floating tables. I don't see any on the 510. Is this a problem on the 510?
All floating tables have locks. The 510 locks "from the inside out" and the 520 locks "from the bottom up".
[*]What else justifies what the catalog says gives "better control, precision and quality performance."
I don't know.
[*]Why would I want to upgrade from a 510 to 520 in the future? For those of you who did, what did you get for the extra $300?
Answered above - Won't need one - Might want one, just so I can have one. The money buys you new rails and a new fence.
Octogenarian's have an earned right to be a curmudgeon.
Chuck in Lancaster, CA
