QCTP finished - quick change tool post

I've finished the tool post , and I like it . The first thing I
noticed , like on the very first cut , it how much less "spring" there
is . After making a cut the tool doesn't leave a mark on the work when I
crank it back to the start of the cut . The lantern always left a spiral
scratch . I have 8 tool holders - so far - we'll see if I need more .
Reply to
Snag
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I bought the setup from Busy Bee designed for the mini lathe to useit on my South Bend 9" similar to one from HF where the tool holders have the male dovetail. The one I got only has one dovetail on the post portion where the HF one has two at 90 deg. I have never found the HF one in stock at the Fort Gratiot MI. store. Anyhow, I bought two sets from Busy Bee and latter got two additioal holders on sale giving me eight holders with 1/2" capacity and two @ 1 1/8" for parting tools etc. On the SB I used a 3/8" grade eight bolt and a 1/2" CRS riser to mount it in place of the lantern tool post. So far I am quite happy with the new setup ant will keep my eye out for more holders.
Reply to
Gerry
Mine was machined from recycled stock in my shop ... if I need more tool holders I'll make them . Five of mine are milled for 5/16 tooling , 2 for 1/4" , and one has a slot 1/2" tall by 3/8" wide for a parting tool (that's not here yet) . If anyone wants the plans I can email them . I got them from the Logan Lathe email list , don't know the origin of them but it's a very nice piston type suitable for 9-10-11 inch lathes . It has dovetails on 2 adjacent sides (it would be easy to add a 3rd) , male on the post . As drawn it's designed for 1/2" cutters , I chose to change that to smaller sizes .
Reply to
Snag
Mine was machined from recycled stock in my shop ... if I need more tool holders I'll make them . Five of mine are milled for 5/16 tooling , 2 for 1/4" , and one has a slot 1/2" tall by 3/8" wide for a parting tool (that's not here yet) . If anyone wants the plans I can email them . I got them from the Logan Lathe email list , don't know the origin of them but it's a very nice piston type suitable for 9-10-11 inch lathes . It has dovetails on 2 adjacent sides (it would be easy to add a 3rd) , male on the post . As drawn it's designed for 1/2" cutters , I chose to change that to smaller sizes . Snag
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I tend to prefer Armstrong-type bit holders over clamping the bare HSS bit in the tool post block, because they fit into tighter places. Yesterday I cut short thread-root-diameter lead-ins on 8-32 screws and had to work very close to the chuck.
The lead-ins aid installing wing nuts outdoors, where I don't want to drop and lose hardware in the dirt or snow. The screws are for a generator sound-damping enclosure made from fireproof suspended ceiling tiles rimmed with sheet metal to keep the edges from crumbling. It's too bulky and fragile to store assembled. Today's project may be a snow- and rain-proof roof for it, and a cut-down pallet for a base.
The screw holding fixture is a cup turned from 1/2" drill rod, with a tapped hole for the screw through the bottom. The operation is more accurate with the cup in a collet, faster in a chuck because the cup is easier to grasp.
Reply to
Jim Wilkins
I can work right up to the chuck with the right grind ... and up to an eighth of an inch with a 1/4" threading cutter . I don't know how much closer you can get .
I've considered an enclosure for my generator , but it's about 50 feet from the house when in (house power) use . Not loud enough inside that it's annoying . And I'm lazy ...
I've used a pair or three nuts to hold a screw or bolt . How do you keep the screw from backing out while cutting ?
Reply to
Snag
That could indicate its being pulled into the part slightly during the cut. I notice this on heavy cuts with aggressive inserts even on the 1440. With a smaller lathe it might not need to be such a heavy cut. They dig into the part and are pulled forward.
A heavy gouge on the return indicates its flexing away from the part during the cut.
A very light (tenth or so) scratch on the return might be as close to perfect as I ever get. Generally I've found I can get sub thousandth reliably be taking two roughly equal finish passes that are still removing a fair amount of material. Measure, cut, measure, cut. DONE. If I am trying to chase better tolerances I'll use a different fresh sharp tool for a final pass, but as you know light passes can be problematic to get good finishes in some materials.
Generally I do not allow the tool to touch the work piece on the return travel at all. Only once in a while if I cam curious about how a new tool/insert performs at a particular FPR, DOC, and RPM at that diameter. 99% of the time its cut and measure. Almost never drag except when learning what exactly is happening so I can plan my cuts.
By adjusting everything on your lathe and replacing the compound with a solid base you can reduce this, but probably not totally eliminate it. I use my compound modestly often so I live with it even though swapping the base and compound probably would not be that time consuming.
ALL machines flex. Even granite machines flex. Just not as much.
Reply to
Bob La Londe
Snag - what metal are you using? Anything special?
Hul
Snag <Snag snipped-for-privacy@msn.com wrote: > I've finished the tool post , and I like it . The first thing I > noticed , like on the very first cut , it how much less "spring" there > is . After making a cut the tool doesn't leave a mark on the work when I > crank it back to the start of the cut . The lantern always left a spiral > scratch . I have 8 tool holders - so far - we'll see if I need more . > -- > Snag > "You can lad a dummy to facts > but you can't make him think."
Reply to
Hul Tytus
Most of it is mystery metal , probably similar to 4140 . This steel was shipping brackets and stiffener members for a CNC router table installed at Memphis Millwork around 2007 or so . The height adjuster buttons are from melted cartridge casings (split necks/Berdan primed) that I cast into rod forms .
Reply to
Snag

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