Lathe Chuck Backplate Identification.Help Needed.

19.5.17. MEW FORUMS.Yes I an back again with yet another hard to solve problem.here is the question-

i have a backplate which is the normal 12 cm dia to suit the normal 4J 12 cm modern chucks.The side facing the tail stock has the standard size spigot and four drilled holes to suit 12 cm (3/34) 4J chuck.However the side facing the spindle seems to me very odd. Theres a parallel unstepped center through hole of apprx 51.8mm. or 2.04 ins. dia. Surrounding that hole are three studs of 9.8 mm dia.There are three tubular nuts which have two flats each for spanner.nuts.The center distances tween studs are all 65 mm.A rough but fairly accurate idea of diag pitch of studs is 75 mm.. The backplate overall is 22mm thick. This is not home made, its been factory produced to a very high std. and theres no ID marks.I reckon this would have cost in uk about £40.00. at least. Has anyone come across this before.Have looked at Int Spindle Nose lists and cannot find the items spec.. Also baffled by not being able to find the spindle nose specs in the Int lists.which is on my Clark Chinese CL 500. This has a chuck mounting flange which is part of the spindle. Theres no tapers or keys or anything which i see in the charts. No I am not an Engineer we are working 7 days a week on Political. Legal. Medical. Govt and air crash issue so have little time except for dogged survival . Soon the UK and Europe will be made aware.No we dont have access to media. .So if we seem a bit dumb its because we are. Read somewhere a week ago that Trivithic was poverty stricken. Would not surprise me in the least.Anyway anyone got any idea what this backplate is used for please. still got the 10 yrs old problems re tooling foir Adcock Horiz No1 1942 Mill. Got frustrated and took a chance with BT 35 which has now cost £100 for 11 tools but, the taper at the large end is about 3/32 too lge.Never mind the drive dogs cos I have not managed to get that far. I reckon thats a brave near miss done in a panic or a stupid thing done in an impatient episode. .Yes I know its in fact NS thats needed but honesty is more easy to find than that.Spose I should not be too upset regarding gambling cos Maxwell lost 50. million just by trying to launch a new newspaper and he, believe it or not was an MP. That old chestnut relativity keeps cropping up. Hope someone can solve the problem of the mystery back plate.Have got a huge victoria dividing head that i keep falling over and I reckon someone might want to buy it to save my legs.Its no good foir me.Got to go to do my Ayurveda tactics.Best regards to all.

Sounds a bit like a Prazzimat backplate though some of the other far eastern lathes are also using a bayonet type stud/nut and keyhole ring now.

Edited By JasonB on 19/05/2017 13:48:10