Not to put anybody down but reading this kinda makes me laugh. Hobby machinists sure do like to make mountains out of mole hills.
We have a lot of time to kill between jobs. We left the real world behind a long time ago and never looked back.
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[Newbie] How To Adjust Tool Height On A Lathe?
- Thread starter dave_r_1
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We have a lot of time to kill between jobs. We left the real world behind a long time ago and never looked back.
It seems like I should comment on stuff on this forum once in a while instead of just browsing. I'm also very new to machining, having had my present lathe less than a year. When I got my present lathe, it came with a 4 way tool post, which like has been mentioned, needed the tools to be shimmed to the correct height. After reading thru forums such as this one, I had already decided to change to a QCTP before I'd even got the new lathe set up. I'm pretty happy with the QCTP, having a lot of my tools already set up in tool holders, making tool changes quick and easy. The 4 way is in a drawer in case I need it, but it hasn't been needed since the change.
Oh, and thanks to all the posters on this forum, I've learned a lot from you.
Steve
Oh, and thanks to all the posters on this forum, I've learned a lot from you.
Steve
I'm with BenzB here as well. When I did my apprenticeship back in the mid 1970's we didn't have qctp's. Just the std 4 way. In fact I hadn't even heard of a qgtp let alone seen one. I'd like to say to the OP that in my opinion dont sweat over getting a qctp if cash is bit tight like it is for a lot of people here (myself included). It doesn't take long to accumulate a range of packers and shims of various thicknesses and you will be surprised how quickly your set up speed with increase with a little practice.
Another source of some good shims, though they are usually not real big, is to pull an old car coil apart. The old oil filled can type. The "iron" core in them is made up from a heap of small shims.
All the best with your machining adventures.
peter
Another source of some good shims, though they are usually not real big, is to pull an old car coil apart. The old oil filled can type. The "iron" core in them is made up from a heap of small shims.
All the best with your machining adventures.
peter
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British Steel
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BenzB said:you want to see how centered your tool is? pinch your 6" ruler between the tool tip and the bar in the chuck. it will either be straight up and down (on center), leaning back (below center), or leaning towards you (above center).
Easy peasy. Only grooving, cut-off tools get real finicky about being on center.
May all your chips be tan and broken
T'other way around surely? Top end of the ruler leaning away = tool too high, towards = too low?
As well as parting and grooving, threading tools need to be on centre height in order to get the correct flank angles - too high or too low and you get a larger included angle, less effective thread depth for the tool advance.
Myself, I think QCTPs rank between cat's pyjamas and dog's wotzits, and I've seen them on older lathes (mine came with a Dickson from the factory in 1953) - but they tend to be Toolroom machines, where the toolmaker would be swapping tools regularly, they were too expensive and not necessary for the machines on the shop floor doing repetitive work. As most on here will be doing one-offs rather than production quantities, a QCTP makes perfect sense!
You do need to build up a stock of holders though, incredibly expensive with a Dickson, which explains my change to a BX...
Dave H. (the other one)
P.S. - if you do have to shim tools, it's a real time saver to buy a stock of rubber bands and use 'em to keep the tool and shims together. Not QCTP Quick, but saves all the grovelling and cuts in the swarf tray where they end up...
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British Steel
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On the subject of tool posts,can issue I am having(hope you guys can help me out here) is it doesn't hold the tool parrelel to the stock. This is very noticeable with cutoff tools. It is a Craftex CT701 from Busy Bee. I'm thinking my only recourse is to A)go to a different tool post, B) a QCTP, or C) re-machine the on it came with. And yes, I am new to lathes and the art of using them......
Not sure exactly what you mean here - do you mean it's not parallel with the cross-slide travel (should be easy to adjust, loosen the nut holding the toolpost down and set the parting/cutoff tool against the face of the chuck if necessary with a parallel / 1-2-3 block between them, then tighten up) or the tool's not square vertically? If it's vertically, it may be the parting blade and its holder aren't a "pair" - some blades are ground with a taper from top to bottom and need a matching holder, some are T shaped and need a groove along the top of the "socket" to let them sit square.
Dave H. (the other one)
It's correct. If the tool pinches below center it tilts the ruler under the stock, hence top end away.
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It's in your perspective, or PoV. Most people use their bodies as a reference when doing this, so yes, below center tools push the top away from the stock, but towards the operator. And of course the opposite with above center tools. So you are both correct, from your respective reference point.
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....Away from WHAT ?
The four way could be dedicated to parting. It is more rigid than a QCTP and once the cut off blade is shimmed on centre you would not have to touch it again. Just swap the 4 way for the QCTP when its time to part.
I see why you would question this now. And you are right. Seems I have been running CNC's with the turret on the far side of the spindle for so long that I forgot that the tool on an engine lathe is on the operator side.
I really need to get my Southbend fixed.