I have a desire to stick an ER type collect chuck on my Harrison L5, now I already have a MT3 ER32 collet chuck but that is limited to only very slightly more than the depth of the collets themselves. So I've bought one of the "plate" type mounting ones (eg https://ebay.us/R4QX5L ) so I can have longer work that will then fit down the spindle. I just need to stick it on a backplate.
There I've come adrift because you can't get backplates for the 1.5"x6TPI spindle and while I can easily get a suitable blank backplate for 160mm or so, nothing smaller seems to be anywhere near the correct thickness (~40mm) for the L5 and while I _can_ I really don't fancy machining the extra 80mm of diameter off! Especially as it's more expensive than buying a blank "slice" of cast iron in a more appropriate size.
The issue is that "cast iron" is recommended for screw on lathe spindles (to prevent bruising to the spindle nose and as they're less likely to be stuck and if they are they're easier to remove) but nowhere can I find any kind of grade recommended (beyond "Drawn" on lathes.co.uk).
While I can buy a suitable slice of Cast Iron Meehanite "bar" ( https://ebay.us/e4diY1 ), Meehanite comes in a bewildering number of grades - https://meehanitemetal.com/wp-conte...wide_Specification_Handbook_ver09.07.2013.pdf and ignoring that the seller of that item doesn't say which it is I have _no_ idea what grade would be best (or even suitable) even if they did.
So, what grade would be recommended for a screw on lathe backplate *or* does anyone have any links to ~80mm+ diameter,~ 40mm+ length backplate blanks?
There I've come adrift because you can't get backplates for the 1.5"x6TPI spindle and while I can easily get a suitable blank backplate for 160mm or so, nothing smaller seems to be anywhere near the correct thickness (~40mm) for the L5 and while I _can_ I really don't fancy machining the extra 80mm of diameter off! Especially as it's more expensive than buying a blank "slice" of cast iron in a more appropriate size.
The issue is that "cast iron" is recommended for screw on lathe spindles (to prevent bruising to the spindle nose and as they're less likely to be stuck and if they are they're easier to remove) but nowhere can I find any kind of grade recommended (beyond "Drawn" on lathes.co.uk).
While I can buy a suitable slice of Cast Iron Meehanite "bar" ( https://ebay.us/e4diY1 ), Meehanite comes in a bewildering number of grades - https://meehanitemetal.com/wp-conte...wide_Specification_Handbook_ver09.07.2013.pdf and ignoring that the seller of that item doesn't say which it is I have _no_ idea what grade would be best (or even suitable) even if they did.
So, what grade would be recommended for a screw on lathe backplate *or* does anyone have any links to ~80mm+ diameter,~ 40mm+ length backplate blanks?