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You just described tramming the head of the mill perfectly. Now you know what tram is and that your mill is in tram.
Rotary Table Alignment
- Thread starter Jmccrack
- Start date
Help Support Home Model Engine Machinist Forum:
This may not effect this problem, but I have came across a bent shaft of the pinion gear and it was giving me a problem with accurately indexing with the rotary table, because of being put away without being careful not to bang the handwheel, they should be resting on a board to where the hand wheel is not touching anything.
Richard Carlstedt
Well-Known Member
Bruce, You got it !
If I may ,I think I can speed up your process (60 years in a shop)
Always do the X axis first ( L & R) ( 9 and 3 O'Clock) ( We called it Twist or Rotate)
Then do Front to Back (called Nod or Tilt) .....but know this
Many guys try to do it at 6 and 12 O'Clock,,,..don't !
Too easy to get confused ( Had many Journeymen even get lost)
Use your Dial indicator at 12 and 3 O'Clock only while adjusting the Nod.
You Nod the headstock to get the two readings the same - discard what you had when doing X axis readings as it means nothing , you want 3 and 12 the same - and when they are the same, then go to 6 and 12 to tweek
Rich
If I may ,I think I can speed up your process (60 years in a shop)
Always do the X axis first ( L & R) ( 9 and 3 O'Clock) ( We called it Twist or Rotate)
Then do Front to Back (called Nod or Tilt) .....but know this
Many guys try to do it at 6 and 12 O'Clock,,,..don't !
Too easy to get confused ( Had many Journeymen even get lost)
Use your Dial indicator at 12 and 3 O'Clock only while adjusting the Nod.
You Nod the headstock to get the two readings the same - discard what you had when doing X axis readings as it means nothing , you want 3 and 12 the same - and when they are the same, then go to 6 and 12 to tweek
Rich
Rich, this is interesting - I'll give it a try next time. Up to now I have found it best to set the nod first, then do the rotate. Just have to remember that the nod motion is out on a cantilever, and take that into account ...
I do X first (9 and 3) but when doing the Nod, I do 6 and 12 and never have had a problem. Why would you want to do 3 and 12? Are you worried that they will get confused by the direction of the indicator and turn the wrong way? These days, i use the dual indicator setups which is easy and fast.
Joe Pi's YouTube videos using a rotary table are quite good
Joe Pi's YouTube videos using a rotary table are quite good
Richard Carlstedt
Well-Known Member
Why would you want to do 3 and 12?
Speed , is the essence of working on setups.
Setups do not pay bills, so in most all machine shops , it's the tricks of the trade that can make a job profitable or not. Fixing Nod is a pain in the butt for most machinists, as evidenced by your purchase of a duel indicator tool ( no offense meant, just most shops do not have them )
With 12 & 3 , no "zeroing" of a indicator is needed- just balance the reading
No Worry about what the reading should be, just the same.
No changing of the machinists position is needed to read the dial as it's easy to view a indicator in a 90 degree arc . (ie, lean over the table on the right side)
Faster as a 90 degree move takes less time than a 180 degree turn .
Many of the Youtube Video's that folks watch show these tricks of the trade.
They are huge time savers. In the Old days, shops did things that are unknown today. Things like .....never use a center drill to start a hole (Lathe) and have a more accurate center for the drill... or never use a height gauge or the dead center for setting tools in a lathe, but use your pocket scale.. .making your 3 jaw more accurate .....and on and on.
Rich
Speed , is the essence of working on setups.
Setups do not pay bills, so in most all machine shops , it's the tricks of the trade that can make a job profitable or not. Fixing Nod is a pain in the butt for most machinists, as evidenced by your purchase of a duel indicator tool ( no offense meant, just most shops do not have them )
With 12 & 3 , no "zeroing" of a indicator is needed- just balance the reading
No Worry about what the reading should be, just the same.
No changing of the machinists position is needed to read the dial as it's easy to view a indicator in a 90 degree arc . (ie, lean over the table on the right side)
Faster as a 90 degree move takes less time than a 180 degree turn .
Many of the Youtube Video's that folks watch show these tricks of the trade.
They are huge time savers. In the Old days, shops did things that are unknown today. Things like .....never use a center drill to start a hole (Lathe) and have a more accurate center for the drill... or never use a height gauge or the dead center for setting tools in a lathe, but use your pocket scale.. .making your 3 jaw more accurate .....and on and on.
Rich
Rich, what is the issue on using a center drill to start a hole in the lathe?
Richard Carlstedt
Well-Known Member
You do not need a centerdrill.
Centerdrills are for making centers in a shaft in order to use a live or dead center, but it's "convenient" for some to use for drilling, but sometimes even centerdrills are off . Also they are 60 degrees and not 118 like a drill.
Do what machinists have done for 100 years, before they had easily obtained centerdrills.
Process
When ever you want to drill in the lathe, always place the bit in the chuck with the cutting lips/edge of the drill in a horizontal position. Bring it up to the work face ...then using your tool bit and cross-slide ,( raise the tool bit up about 1/8 ") and then move it in maybe 1/4" to 1/2 " behind the cutting flutes and push the drill off center about .010" ( the above depends on the size of the drill-) . Now this is a two hand operation advance the drill so the divot in the work piece is about 1/2 the drill size and when that point is reached -keep feeding the drill in and at the same moment retract the crossfeed !
Now you have a perfect centered hole start !
Technical Data explanation
So here is what is happening . Pushing the drill away from you makes it cut only on the far side cutting lip( it becomes like a boring bar in miniature) The result is a conical shaped hole with a *** in the middle and is a true centered machined surface ( like a boring tool). Now what you want is a cone length longer than the *** length - when this is reached ( 50 % to 90 % diameter) and the drill forced in (without side cross-feed pressure !) the hole forces the drill lip inward as the force needed to cut the *** is less than allowing the drill lip to cut the cone .
A few notes
Doing the above saves setup time . The machinist immediately goes to his drill , no swapping chucks or using the Jacobs key.
With Aloris Tool Posts , it easy to raise the tool bit and then drop it back into place as I suggested here, but when the old guys used Lantern Posts, they just made sure the tool bit's cutting edge did not touch the cutting flute of the drill bit and used the "Heel" of the toolbit when touching the drill bit.
In fact, the old guys did not even "face the end" of the work before drilling, and used the above method to "mini-face" the saw cut stock with the drill a small amount before proceeding as noted.
All the above is for those who wish to expand their skills .
It also adds to satisfaction at using your skills in new ( or old ! ) ways
Rich
Centerdrills are for making centers in a shaft in order to use a live or dead center, but it's "convenient" for some to use for drilling, but sometimes even centerdrills are off . Also they are 60 degrees and not 118 like a drill.
Do what machinists have done for 100 years, before they had easily obtained centerdrills.
Process
When ever you want to drill in the lathe, always place the bit in the chuck with the cutting lips/edge of the drill in a horizontal position. Bring it up to the work face ...then using your tool bit and cross-slide ,( raise the tool bit up about 1/8 ") and then move it in maybe 1/4" to 1/2 " behind the cutting flutes and push the drill off center about .010" ( the above depends on the size of the drill-) . Now this is a two hand operation advance the drill so the divot in the work piece is about 1/2 the drill size and when that point is reached -keep feeding the drill in and at the same moment retract the crossfeed !
Now you have a perfect centered hole start !
Technical Data explanation
So here is what is happening . Pushing the drill away from you makes it cut only on the far side cutting lip( it becomes like a boring bar in miniature) The result is a conical shaped hole with a *** in the middle and is a true centered machined surface ( like a boring tool). Now what you want is a cone length longer than the *** length - when this is reached ( 50 % to 90 % diameter) and the drill forced in (without side cross-feed pressure !) the hole forces the drill lip inward as the force needed to cut the *** is less than allowing the drill lip to cut the cone .
A few notes
Doing the above saves setup time . The machinist immediately goes to his drill , no swapping chucks or using the Jacobs key.
With Aloris Tool Posts , it easy to raise the tool bit and then drop it back into place as I suggested here, but when the old guys used Lantern Posts, they just made sure the tool bit's cutting edge did not touch the cutting flute of the drill bit and used the "Heel" of the toolbit when touching the drill bit.
In fact, the old guys did not even "face the end" of the work before drilling, and used the above method to "mini-face" the saw cut stock with the drill a small amount before proceeding as noted.
All the above is for those who wish to expand their skills .
It also adds to satisfaction at using your skills in new ( or old ! ) ways
Rich
The double indicator method is so fast - no changing positions, etc - that I am surprised shops do not use it more. But I do realize it is another piece of "kit" that you have to have hanging around. In my opinion, the Starrett/SPI style of spindle square is the best because calibrating it is so easy - just rest on a surface plate and set dials to zero One really nice seldom mentioned feature is that the same spindle square can be used with a sine bar to set an accurate tilt to the head if needed. Practical Machinist just published a brief article on tramming. In the linked video, he is using the double style that I do not like as much because of how it has to be calibrated - takes longer.
https://www.practicalmachinist.com/...edium=email&utm_campaign=2020Chatter_February
Rich, I really like the description for drilling that you gave -I will have to try that. Thank you for taking the time to explain it so well. For the same reasons, I like Joe Pi's videos - just like you, he takes the time to not only tell you what to do but why. That added knowledge makes me much better at machining and adapting techniques to new situations. How he used spacer blocks on a recent video where he was using a rotary table to make some parts for the cannon is a good example. It was not something that would have occurred to me but now I can add it to my repertoire. Unfortunately, lots of the cumulative machining knowledge gathered over the years is going to be lost, I am afraid. So I appreciate whenever I see someone passing it on to others. I just purchased Tom Lipton's Metalworking, Sink or Swim where it looks like he has tried to document some of that knowledge.
I have asked this question on another forum and never got an answer: Why do people always tram their table and then mount a vise and assume the tram to the vise is good? Shouldn't you always tram your work holding device, the table if clamping to the table and the vise if using the vise to hold the material? It seems like tramming just to the table potentially adds error when using the vise.
Ken
https://www.practicalmachinist.com/...edium=email&utm_campaign=2020Chatter_February
Rich, I really like the description for drilling that you gave -I will have to try that. Thank you for taking the time to explain it so well. For the same reasons, I like Joe Pi's videos - just like you, he takes the time to not only tell you what to do but why. That added knowledge makes me much better at machining and adapting techniques to new situations. How he used spacer blocks on a recent video where he was using a rotary table to make some parts for the cannon is a good example. It was not something that would have occurred to me but now I can add it to my repertoire. Unfortunately, lots of the cumulative machining knowledge gathered over the years is going to be lost, I am afraid. So I appreciate whenever I see someone passing it on to others. I just purchased Tom Lipton's Metalworking, Sink or Swim where it looks like he has tried to document some of that knowledge.
I have asked this question on another forum and never got an answer: Why do people always tram their table and then mount a vise and assume the tram to the vise is good? Shouldn't you always tram your work holding device, the table if clamping to the table and the vise if using the vise to hold the material? It seems like tramming just to the table potentially adds error when using the vise.
Ken
Rich, thanks for the explanation. That's a technique I've not encountered before!
Ken, here's my thinking about the vise: the key issue is that the movement of the work piece past the tool in the spindle is going to be controlled by the table, not by the vise. Thus, if one trammed to the vise and not to the table, one will wind up with results other than what are expected.
The answer, of course, is to square the vise to the table - typically along the X axis (though could be along the Y) unless one needs to cut at an angle, but equally important is that the bottom of the vise clamping area must be parallel to the bed - if it is not, no amount of tramming will correct the problem; the vise must be replaced or repaired.
Ken, here's my thinking about the vise: the key issue is that the movement of the work piece past the tool in the spindle is going to be controlled by the table, not by the vise. Thus, if one trammed to the vise and not to the table, one will wind up with results other than what are expected.
The answer, of course, is to square the vise to the table - typically along the X axis (though could be along the Y) unless one needs to cut at an angle, but equally important is that the bottom of the vise clamping area must be parallel to the bed - if it is not, no amount of tramming will correct the problem; the vise must be replaced or repaired.
Thanks. I was not referring to indicating the vise to the table travel but making sure it was perpendicular to the spindle in the x-y plane (parallel to the bed as you mentioned).
I think I understand what you are saying, it is the "cosine" problem. If the vise is not parallel to the table, the dimension of travel on the dial/screw will be different than the amount of travel of the cutter on the surface of the part as well as the depth of cut varying. Tramming to the vise will give you perpendicular sides but inaccurate dimensions. Tramming to the table will give you known travel distances but your sides will not be perpendicular if the vise is off relative to the table. I will indicate the height of the vise holding area after tramming to the table and see if there are any differences across the vise. I have always trammed the table until the last couple of times. The projects I have done since are not ones where I could see the error if I created one. If the vise is good, there would be no difference. Worth checking because if the vise is parallel to the bed, then tram can be checked without removing the vise. Saddle wear on a heavily used mill could add error if tramming to the side of where your vise is located. I would surprised if most vises are off significantly enough to notice.
Or I still have it wrong
Ken
I think I understand what you are saying, it is the "cosine" problem. If the vise is not parallel to the table, the dimension of travel on the dial/screw will be different than the amount of travel of the cutter on the surface of the part as well as the depth of cut varying. Tramming to the vise will give you perpendicular sides but inaccurate dimensions. Tramming to the table will give you known travel distances but your sides will not be perpendicular if the vise is off relative to the table. I will indicate the height of the vise holding area after tramming to the table and see if there are any differences across the vise. I have always trammed the table until the last couple of times. The projects I have done since are not ones where I could see the error if I created one. If the vise is good, there would be no difference. Worth checking because if the vise is parallel to the bed, then tram can be checked without removing the vise. Saddle wear on a heavily used mill could add error if tramming to the side of where your vise is located. I would surprised if most vises are off significantly enough to notice.
Or I still have it wrong
Ken
Richard Carlstedt
Well-Known Member
Discussing vises is a good way to start arguments
I have had a 5 inch Kurt in my shop for 43 years and it is as close to perfect as they come. I was given a 4 inch Kurt imitation made in India and it was a piece of garbage. Took about 30 hours of rework to get it square and flat. I would say 60 % of my work is done without a vise , so I do not worry about vise tramming as I use the table and clamps. When you talk about Vice tramming , I assume you mean tramming the top of the vise where it is flat ?
A quality Vise like a Kurt is very flat and is only required to be checked once .
Should have mentioned this earlier
Always tram with the quill fully extended and clamped ( Most accurate tramming ) and then fully retracted and recheck to determine if quill wear has affected the tram
Rich
I have had a 5 inch Kurt in my shop for 43 years and it is as close to perfect as they come. I was given a 4 inch Kurt imitation made in India and it was a piece of garbage. Took about 30 hours of rework to get it square and flat. I would say 60 % of my work is done without a vise , so I do not worry about vise tramming as I use the table and clamps. When you talk about Vice tramming , I assume you mean tramming the top of the vise where it is flat ?
A quality Vise like a Kurt is very flat and is only required to be checked once .
Should have mentioned this earlier
Always tram with the quill fully extended and clamped ( Most accurate tramming ) and then fully retracted and recheck to determine if quill wear has affected the tram
Rich
Fortunately, I have a Kurt. I trammed the bottom where one's parallels would sit. My spindle square just fits inside the fully open vise.
Excellent idea to compare extended vs retracted. I try to keep the quill retracted for stiffness and have always trammed that way because that is how I use it but I can see where tramming extended would make any "errors" more noticeable.
Ken
Excellent idea to compare extended vs retracted. I try to keep the quill retracted for stiffness and have always trammed that way because that is how I use it but I can see where tramming extended would make any "errors" more noticeable.
Ken
we always center drilled a spotting drill nicer but kinda rare the most accurate cdrill technique was to just barely start the tip the stub tip is the right angle don't go deeper than the tips of the first set of flutes the idea is to have the drill engage on the cone shaped hole, not a sharp hole edge. the work surface was as smooth as possible surface ground often even surface lay direction made a difference , the idea was to load each flute evenly right from the start and not get anything that would deflect the drill tip like a groove or ridge drilled hole locations were on the order of +-.001 if they were in a hurry and +-.0002 as measured on the CMM if looking for accur.
