The Lower Guard you show is NOT the actual Lower Saw Blade Guard for your 510. It is a stripped-down version of the guard made for the Mark V 500 with the original Table System to use as a Dust Collector for the Sanding Disk. If you look at the picture I posted you will see yours does not have the rods, springs and moving part.
In your second picture the extendable part of the Lower Guard is catching the Guard part attached to the Table Tie Bar thus not allowing the Table to go any lower. As already been mentioned the knurled knobs need to be loosened and the outer part of the guard pushed back towards the quill before lowering the Table. That will allow the part attached to the Table Tie Bar to go outside the Lower Saw Blade Guard.
Russ
Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
In your picture below the arrow points to the spacer on the rear Way Tube JPG was referring to. It spaces the Carriage from the Headstock the correct distance for the Saw Blade to be in the Table Insert Slot without extending the Quill. This makes the set up for sawing much easier and repeatable. Once set correctly it will be the correct position in later set ups.
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jimbrauer 1 spacer arrow.jpg (135.5 KiB) Viewed 47613 times
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In your picture below this may better explain what I was referring to in my previous post. The Edge of the "Lower Guard" indicated by the red arrow should go behind the part attached to the table Tie Bar indicated by the green arrow. Not vice versa as currently shown in your picture below. That is what is causing the Table to not go lower.
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jimbrauer 2 Guard arrows.jpg (142.83 KiB) Viewed 47613 times
Russ
Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
As usual from thee, a very accurate, detailed explanation!!!
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
You can also experiment with slightly tilting the table (just a degree or two) while adjusting blade height, then returning to square. Sometimes this gets around the physical interference long enough to make your adjustment.
Tilting the Table to clear the part of the Lower Guard Assembly mounted to the Quill and the part of the Lower Guard Assembly attached to the Table Tie Bar will not change the interference shown in the picture in my previous post.
Russ
Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.