5/16 x 14 Tap Drill query

keninar

Registered
New kid on the block here with what is probably a simple question regarding joint pin installation.

Task ahead is to install a 5/16 x 14 self-centering pin. Understand and can achieve the boring successfully, but not having much luck in identifying the appropriate tap drill for the 5/16 x 14 anchor. Can look up the sizes for 18 and 24 tpi – but 14 isn’t listed in the resources I’m reviewing. Any thoughts from the veteran makers?

Thanks in advice and look forward to learning much from this group.
Ken
 

Kim Bye

AzB Silver Member
Silver Member
I guess it depends on your 5/16-14 pin, but 1/4" is a good place to start.
 

Dave38

theemperorhasnoclotheson
Silver Member
.250" drill, or in my case, I use a .250" facecutting 4 flute endmill, then blow out the chips and tap it.
Dave
 

JC

Coos Cues
Loose threads and thin epoxy for self centering pin anchor threads. If the threads down there are too tight the lower threads on the pin can fight the self centering and be a problem to get dead nuts straight. Same with thick glue.

I use a 17/64 drill. Just a good quality mechanics length bit is all you need. It's not critical these threads be aligned perfectly, just that they are not tight causing sideways tension on the pin. Also be sure to cut them deep enough so the pin doesn't get tight at the bottom of the threads as they narrow from the tap taper for the same reason.

JC
 

CuesRus1973

AzB Silver Member
Silver Member
Loose threads and thin epoxy for self centering pin anchor threads. If the threads down there are too tight the lower threads on the pin can fight the self centering and be a problem to get dead nuts straight. Same with thick glue.

I use a 17/64 drill. Just a good quality mechanics length bit is all you need. It's not critical these threads be aligned perfectly, just that they are not tight causing sideways tension on the pin. Also be sure to cut them deep enough so the pin doesn't get tight at the bottom of the threads as they narrow from the tap taper for the same reason.

JC

Everybody has their own machining practices. This would be my personal choice. This is not to say that .250" is wrong by any means. What works for some may or may not for others.
I will suggest making dry run assemblies on test dowels to see what works best for you before you go into a cue.
 

Michael Webb

AzB Silver Member
Silver Member
Everybody has their own machining practices. This would be my personal choice. This is not to say that .250" is wrong by any means. What works for some may or may not for others.
I will suggest making dry run assemblies on test dowels to see what works best for you before you go into a cue.


Tap tap. I agree. There are many variations. I measure them all.

IMG_20190719_015443.jpg
 

cueman

AzB Gold Member
Gold Member
Silver Member
I use regular full thread 5/16-14 pins and use a 1/4" carbide three flute drill bit and have really been happy with them.
 

CuesRus1973

AzB Silver Member
Silver Member
I use regular full thread 5/16-14 pins and use a 1/4" carbide three flute drill bit and have really been happy with them.

Cueman has been in the business as long or longer than anyone. You may find other ways to do things, but you can't go wrong with his advice.
 

JC

Coos Cues
Everybody has their own machining practices. This would be my personal choice. This is not to say that .250" is wrong by any means. What works for some may or may not for others.
I will suggest making dry run assemblies on test dowels to see what works best for you before you go into a cue.

This is how I learned not to use thick glue. The pin is dead nuts dry and can't seem to get it straight with the glue in the hole.

JC
 

Michael Webb

AzB Silver Member
Silver Member
I use regular full thread 5/16-14 pins and use a 1/4" carbide three flute drill bit and have really been happy with them.


Amen.
My can of worms usually. I hate joint screws with shanks. I have them but I don't use them unless I have to. Usually on a repair. I remember when shanks weren't even offered. I'm sure you do too.
 

Mcues

AzB Silver Member
Silver Member
PIns

I use a 17/64 carbide three fluted bit and then I heat my epoxy a bit..no complains and I don't have to leave it on the lathe while drying. :)

Mario
 

Michael Webb

AzB Silver Member
Silver Member
The use of 17/64" has me stumped. That thing is huge for it's use here. I've done 1/4" and an F drill as the largest.
 

JC

Coos Cues
I use a 17/64 carbide three fluted bit and then I heat my epoxy a bit..no complains and I don't have to leave it on the lathe while drying. :)

Mario



What amount of TIR can you spot with your naked eye?

Do you measure it with a dial indicator before un lathing it to be sure?

Is it straight enough if you can't detect any run out visually?

What if it's not? What do you do at that point to fix it?

What I did was found a process that worked better for me.

I didn't ask anyone and oddly it's similar to what you do.


JC
 
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Mcues

AzB Silver Member
Silver Member
What amount of TIR can you spot with your naked eye?

Do you measure it with a dial indicator before un lathing it to be sure?

Is it straight enough if you can't detect any run out visually?

What if it's not? What do you do at that point to fix it?

What I did was found a process that worked better for me.

I didn't ask anyone and oddly it's similar to what you do.


JC


Visually what is that? LOL
 

Mcues

AzB Silver Member
Silver Member
The use of 17/64" has me stumped. That thing is huge for it's use here. I've done 1/4" and an F drill as the largest.

Only on self aligning pins which I like :) the accuracy of that shoulder determines more than the bottom threads. In my opinion :) of course.

Mario
 

JC

Coos Cues
The use of 17/64" has me stumped. That thing is huge for it's use here. I've done 1/4" and an F drill as the largest.

On the modified pins it's all about the barrel for centering. Thus the thin glue.

The anchor threads do just that, anchor. The epoxy takes care of the play in the bottom threads. There's plenty of meat there to hold it. All we need is the pin to be straight and not come out with the shaft when breaking down the cue right?

By making the threads slightly looser I have found the pin sits nice and tension free in the bore of the wood. Once the epoxy hardens the threads with .015 more clearance are just fine for the job. Haven't tried an F drill and it's likely just fine at .257". I will try it now though. The less clearance in every spot you're gluing that you can achieve seems a good goal.

When I started out I read Chris' book many times. He talks about pushing the pin with the cross slide if it's not turning true after installation. This works but it's not ideal IMO.

If the pin is threaded all the way this may be best but you sure don't want to be trying to center a modified pin after installation.

Just my thoughts

JC
 

Michael Webb

AzB Silver Member
Silver Member
On the modified pins it's all about the barrel for centering. Thus the thin glue.

The anchor threads do just that, anchor. The epoxy takes care of the play in the bottom threads. There's plenty of meat there to hold it. All we need is the pin to be straight and not come out with the shaft when breaking down the cue right?

By making the threads slightly looser I have found the pin sits nice and tension free in the bore of the wood. Once the epoxy hardens the threads with .015 more clearance are just fine for the job. Haven't tried an F drill and it's likely just fine at .257". I will try it now though. The less clearance in every spot you're gluing that you can achieve seems a good goal.

When I started out I read Chris' book many times. He talks about pushing the pin with the cross slide if it's not turning true after installation. This works but it's not ideal IMO.

If the pin is threaded all the way this may be best but you sure don't want to be trying to center a modified pin after installation.

Just my thoughts

JC


Thank you John and Mario.
Pushing the pin with the cross slide is kind of interesting but if you indicate the cue before you prep for the joint screw, it might still be more logical to put the cue between centers and indicate it afterwards. A few thousanths is a few thousanths.
On the bottom threads of the 5/16x14 screws with shanks, what is the o.d. of them. Are they like the example I provided or different. On my example of .274x14 and the use of 17/64" (.265) that only leaves 4.5 thou per side not counting if the bit has run out or not. Not much of an anchor.
 
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