Hello,
I have 125 mm center height lathe (CQ9325 10 x 18" 250x450mm), much like this:
http://users.picknowl.com.au/~gloaming_agnet/cq9325rev.htmltop slide:
http://users.picknowl.com.au/~gloaming_agnet/cq9325rev-b.htmlThe original top slide and it's mounting is too weak and I have replaced it with simple mount for QC-tool-post. However top slide has it's uses and I'm thinking of building one, but I never have build such thing and would appreciate some opinion.
I can think three cenarios for top side use:
* Threading (even the original would do)
* Short tappers, like ER collet holders, MT1/2 maybe even #3 and such (the original has very short travel)
* Fine feed, when adjusted into acute angle, but then handles could foul cross slide handles or tail stock
Am I missing here anything really tactical?
I have round GI stock OD115 mm length 190 mm and some shorter/thicker pieces to work with. I think this would allow me build big enough dove tail slide for 85 mm effective movement.
* What mechanism would be good for swivel?
Original is like this:
http://users.picknowl.com.au/%7Egloaming_agnet/1254.jpgMyford M10 type I'm familiar with
http://www.lathes.co.uk/myfordml10/img6.gifMyford 7 type:
http://www.lathes.co.uk/myford-ml7/img21.jpgI don't want to carve too much into original cross slide assembly and I don't have too much headroom there, I'm thinkking very simple bolt down flange structure. Simple structure means that I need to remove bolts to move it extremes, but when I got it was turned most of time to 30 decree mark (half of 60 decree thread flank or a little less with carbide inserts to prevent rubbing on flank).
* Opinion about lead screw?
I'm not completely happy with cross slide "almost" metric lead and 100 division collar. I'm little tempted to replace cross slide screw with 16x4 mm left hand acme screw, which seems to be fairly common size. Although it might be mostly viable only with new cross slide. I can find 14x4 and 12x3 mm screws on catalogs....I'm wondering if I run out of space for 16 mm screw on top slide would it be very confusing to have different lead on top slide and cross slide? Cross slide and top slide leads are all different on all of my three lathes, but is there an instance this actually would be a problem?
I'm not aiming here for absolute accuracy (bit pointless considering rest of the lathe) but more into confort and reliability.
* Opinion about lead screw placement? Usually it's on the middle, but some smaller and clock making lathes tend to have it much offset or even outside of the dove tail slide. This will cause some assymmetric moment, but how much it is of a factor here? I tend to use top slide mainly for finishing cuts.
* Gib strip placement - of cource towards operator side when crank is on the right? Reasoning is that on "normal" orientation forces act more on fixed side and less on the side that has a gib. Am I missing here something?
* Gib type? I don't see many slide locks on top slides, but for me it's a stiff top slide or quick change between tool post that has top slide and another without. Is this a place for standard set screw gib or something more fancy?
Pekka