Indicating the joint pin

S

sliprock

AzB Silver Member
Silver Member
I was wondering what method you guys use to indicate standard joint pins.
By standard, I mean the normal 5/16 and 3/8 pins that don't have the piloted nose like the radial,uni-loc,etc. How do you get an accurate reading without the threads interfering.

Also, how much runout do you think is possible without affecting the cues straightness. Thanks
 
sliprock said:
I was wondering what method you guys use to indicate standard joint pins.
By standard, I mean the normal 5/16 and 3/8 pins that don't have the piloted nose like the radial,uni-loc,etc. How do you get an accurate reading without the threads interfering.
Also, how much runout do you think is possible without affecting the cues straightness. Thanks
Click to expand...

If the hole is straight there will be little or no runout.
You install the pin just after making the pin hole ( it should be a snug fit) and spin the lathe.
If you SEE runout at the tip of the pin your hole is crooked or the pin is bent.
If you can not SEE any runout you did a good job.

The fit of a lot of 3/8 x 10 and 5/16 pins in relation to the shaft hole are sloppy.
(the shaft wobbles around when you screw it on)
They depend on the faces of the joint to align the shaft straight with the cue.
Five or six thousands of runout would not effect these pins very much.
However, as a cuemaker I take great care that the hole the pin goes in is very true to the center line of the cue and the pin runs true to that line. Makes things a lot easier when things are round, concentric, and true.
Some cuemakers will drill a small center hole in the end of the pin to aid with alignment or to provide a reference for later cuemaking operations.

Willee
 
WilleeCue said:
If the hole is straight there will be little or no runout.
You install the pin just after making the pin hole ( it should be a snug fit) and spin the lathe.
If you SEE runout at the tip of the pin your hole is crooked or the pin is bent.
If you can not SEE any runout you did a good job.

The fit of a lot of 3/8 x 10 and 5/16 pins in relation to the shaft hole are sloppy.
(the shaft wobbles around when you screw it on)
They depend on the faces of the joint to align the shaft straight with the cue.
Five or six thousands of runout would not effect these pins very much.
However, as a cuemaker I take great care that the hole the pin goes in is very true to the center line of the cue and the pin runs true to that line. Makes things a lot easier when things are round, concentric, and true.
Some cuemakers will drill a small center hole in the end of the pin to aid with alignment or to provide a reference for later cuemaking operations.

Willee
Click to expand...


Sorry If I'm off topic, but I believe I saw a good point in there that probably should've been mentioned in another thread for those that don't already know. The center drilling of the pin has It's advantages, but is not really an alternative to to installing It straight in the first place. You may be able to get away with It on a plain jane, or by going in earlier with It, but not recomended, and can throw the grain lines off center If you depend on it too much.
I would do the same either way, but On a cue with ring work, points, etc, I definatly would'nt depend on centering off the pin to trim, if it was installed previous to the points & ringwork, unless it was installed straight in the first place, because It can throw all that stuff off when you trim. It's hard enough to get It all lined up in the first place, just to trim them, and cause everything to run off on Your final cuts.

The runnout on the pin- I have indicated as easily as just doing It off the joint, and then off the back of the cue to make sure it was chucked up correctly before I even drill, and tap. I can see the runnout in the end of the pin if I indicate the joint that way, and know by sight if the pin is exceptable or not, because It's usually very obvious, but I suppose some people indicate the pin also. However someone goes about It, Installing the pin Is a critical point in the build, and It pays to figure out whatever works best for you, so the question has quite a bit of merit.

I also agree that the faces are important in how the butt section and shaft matchup, regardless if the pin is straight or not.

Greg
 
Indicating threads

sliprock said:
I was wondering what method you guys use to indicate standard joint pins.
By standard, I mean the normal 5/16 and 3/8 pins that don't have the piloted nose like the radial,uni-loc,etc. How do you get an accurate reading without the threads interfering.

Also, how much runout do you think is possible without affecting the cues straightness. Thanks
Click to expand...

If you only use one or two thread sizes make a female gage from UHMW plastic or Delrin. In a metal lathe in one set up ( maintains concenticity ) turn a convenient diameter then center drill, drill, and cut the desired thread with a tap then part off gage. Screw gauge onto joint pin to indicate.
More accurate is to make 6 metal gauges for each thread size you use in one set up by boring the hole after turning the diameter then turning the threads with a boring bar. This gives perfect concentricity but is more difficult to do. The six gages should be from nominal diameter to -.003 inch by -.0005 inch steps. Use the gauge with the best fit. If all your pins are the same size use the pin to check the thread gauge thread until a snug fit is achieved and only make one thread gauge.


Charlie McKay
 
Trueheart said:
If you only use one or two thread sizes make a female gage from UHMW plastic or Delrin. In a metal lathe in one set up ( maintains concenticity ) turn a convenient diameter then center drill, drill, and cut the desired thread with a tap then part off gage. Screw gauge onto joint pin to indicate.
More accurate is to make 6 metal gauges for each thread size you use in one set up by boring the hole after turning the diameter then turning the threads with a boring bar. This gives perfect concentricity but is more difficult to do. The six gages should be from nominal diameter to -.003 inch by -.0005 inch steps. Use the gauge with the best fit. If all your pins are the same size use the pin to check the thread gauge thread until a snug fit is achieved and only make one thread gauge.


Charlie McKay
Click to expand...
Sounds like a collet closer type setup work. :)
My 6-jaw chuck has a .002 runout and chucking up on threaded pins is not that easy. The new pins from Atlas have unthreaded alignment barrel which makes them easier to work with.
 
Trueheart said:
If you only use one or two thread sizes make a female gage from UHMW plastic or Delrin. In a metal lathe in one set up ( maintains concenticity ) turn a convenient diameter then center drill, drill, and cut the desired thread with a tap then part off gage. Screw gauge onto joint pin to indicate.
More accurate is to make 6 metal gauges for each thread size you use in one set up by boring the hole after turning the diameter then turning the threads with a boring bar. This gives perfect concentricity but is more difficult to do. The six gages should be from nominal diameter to -.003 inch by -.0005 inch steps. Use the gauge with the best fit. If all your pins are the same size use the pin to check the thread gauge thread until a snug fit is achieved and only make one thread gauge.


Charlie McKay
Click to expand...

Another option probaby easier and about as accurate as would be necessary, is to drill and tap a 3/4" diameter piece of delrin (which closes up a bit after tapping for a tighter thread).
Then chuck up a piece of mild steel and chase the male thread. Screw the delrin gage on and turn to cleanup.
 
Eyefull said:
Another option probaby easier and about as accurate as would be necessary, is to drill and tap a 3/4" diameter piece of delrin (which closes up a bit after tapping for a tighter thread).
Then chuck up a piece of mild steel and chase the male thread. Screw the delrin gage on and turn to cleanup.
Click to expand...

Yes that is very accurate if the male thread is turned in the lathe to a tight fit and used as a mandrel to turn the outside diameter of the Delrin internally threaded rod. Chris Hightower uses this technique for making perfectly concentric brass joint inserts. Since the threaded mandrel is never removed from the chuck it has the accuracy of the lathe head bearings.

Charlie McKay
 
Eyefull said:
Your method would work if the threads are cut perfectly concentric with the major dia. (which is probably the case), but runout on a thread really should be checked from the pitch dia., which locates the female.
Click to expand...

I agree 100% with what you are saying. I was simply answering the posted question of how to indicate the OD of the pin. If the question was how to have your inserts run concentric with your pins that would be a completely different thing. IMO because screw threads centre themselves on the flank of the thread not on the OD or ID. (standard 60deg v-thread that is ) Unless you have an almost perfect fit between you insert and pin then where your shaft will run in relation to your pin is still a guessing game regardless if your pin runs true. Thus the reason for piloted joints or non standard thread forms like southwest. Standard screw threads were not designed as an accurate means of aligning two mating parts but only to fasten the two parts together.
 
Thread Alignment

Canadian cue said:
I agree 100% with what you are saying. I was simply answering the posted question of how to indicate the OD of the pin. If the question was how to have your inserts run concentric with your pins that would be a completely different thing. IMO because screw threads centre themselves on the flank of the thread not on the OD or ID. (standard 60deg v-thread that is ) Unless you have an almost perfect fit between you insert and pin then where your shaft will run in relation to your pin is still a guessing game regardless if your pin runs true. Thus the reason for piloted joints or non standard thread forms like southwest. Standard screw threads were not designed as an accurate means of aligning two mating parts but only to fasten the two parts together.
Click to expand...

Good to hear from another Canadian, eh.

I am tool and die maker by trade, cuemaker by desire.

Threading is a very highly developed machining practice. Metal threads have varying degrees of accuracy which are referred to as the fit or grade of thread. Some threads have zero clearance and give perfect location like micrometer threads. If you cut your own threads on a lathe it is normal to only have about 1 thousanth if an inch clearance between the male and female thread giving excellent location. Close fitting threads stay tight better but are difficult to maintain and keep clean enough to operate smoothly. Compromise is to pilot threads with a solid diameter and use a looser fit. Threads locate on the thread faces and are usaully measured at the pitch diameter for machining purposes. If you want to go into information overload try reading the thread section of the Machinery Handbook.

Charlie McKay
 
Trueheart said:
Good to hear from another Canadian, eh.

I am tool and die maker by trade, cuemaker by desire.

Threading is a very highly developed machining practice. Metal threads have varying degrees of accuracy which are referred to as the fit or grade of thread. Some threads have zero clearance and give perfect location like micrometer threads. If you cut your own threads on a lathe it is normal to only have about 1 thousanth if an inch clearance between the male and female thread giving excellent location. Close fitting threads stay tight better but are difficult to maintain and keep clean enough to operate smoothly. Compromise is to pilot threads with a solid diameter and use a looser fit. Threads locate on the thread faces and are usaully measured at the pitch diameter for machining purposes. If you want to go into information overload try reading the thread section of the Machinery Handbook.

Charlie McKay
Click to expand...


Hi Charlie,
There are not to many makers north of the border. Where are you located?
In response to your post, being a tool and die maker you would have to agree that it it is rare if any that you see a designer/engineer use a screw thread as a means of accurate location. It is almost always in conjunction with another locating device (dowel pin, turned shoulder ). For example just look at a threaded spindle nose on a lathe there is always a locating shoulder at the base of the thread even though the thread was accuratly machined and ground.
 
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