Shars 6" Fully Machined Threaded Back Plate 1-1/2-8 For 3 or 4 Jaw Self Center Chuck 202-6109 S

Good product. Works as it should.

Slight machining was done to fit it to my chuck as required. Over all very pleased

As some others have commented, the axial runout is pretty bad, 0.025" on the one I got. But, since you have to turn down the mounting shoulder anyway, a truing pass over the face isn't all that big a deal. So, I would call it 'mostly fully machined'. It appears that the cause is the center bore not being all that perpendicular to the axis. Still, you need one to mount the Shars chucks, and it's a lot easier than machining one up yourself. For the price, totally acceptable.

Threads fit correctly, mounting holes correctly located and there was enough material to machine the registration shoulder concentric to my lathe.

Two issues kept me from rating this higher. The threads don’t start for about 1/2 inch causing a reduced thread engagement on my Atlas lathe. I had to machine off about 1/4 inch of the non threaded back to ensure I had at least 5 threads engagement on my 1 1/2 -8TPI spindle.Also backplate only came with 2 jacking screws. Plate is machined and threaded expecting 3 jacking screws to separate backplate from chuck.

The order arrived on time. The lathe back plate is made from cast iron which does not machine very well, but it will do. the tolerances are as specified so it will suite my purposes.

It fit just fine on my new 6 inch chuck. There was a very minimal amount of milling necessary. With a small amount of adjusting the run out was between 1 and 2 thousands which is plenty good for my hobby type of work.

Packaging was fine. And it arrived in good shape. But what the point when the product itself has so much runout you have to turn it down and pray it runs true with the chuck.I returned the first and was shipped a replacement thinking the first was a lemon. Turns out thats standard for this product and now i can't return it as I turned it true. So warning all future purchasers.... don't do it.