Radial Tap issue (new to repairs)

S

surffisher2a

AzB Silver Member
Silver Member
I got my cuesmith lathe in February and started doing repairs on cues. My friend has a shaft that he wanted retapped to radial. So I drilled / bored it out, installed a phenolic plug that I got from Unique (followed their directions for install). That went perfect and got a real nice fit with the plug. My problem now comes getting the correct size hole to run the radial tap through (also got from unique (so its not an official uni-loc). So before I drilled into my nice new phenolic insert, I tested on a couple dowel rods just to make sure everything goes OK. So I started with a 5/16 bit that uni-loc recommended for tapping the radial shaft and then ran the tap through it. It went really easy but I barely had any thread depth. I did this a couple times really being careful but still had almost non existent threads. The dowel did screw onto my cue though, so there was at least some thread there. So I thought the 5/16 bit I had was just a tad over sized, so I bought an "N" bit, which is just a tad smaller than 5/16th. I did another test in a dowel or two and i am still no happy with the results, just slightly better than the previous attempts. I did try the "N" bit on an old broken maple shaft, thinking that the dowel wood was too soft and was just tearing the threads. I didn't see any improvement with using hard maple.

So I was just going to purchase a 19/64" bit and try that, however I don't want to keep wasting money on these bits and I feel like I may be missing something since the recommended size is 5/16th. Going a couple sizes smaller than that just doesn't seem right too me.

So I am just curious what size pilot hole everyone is using with their radial taps (specifically the ones from unique).

I did measure the pilot holes I been drilling with my bits and they all seemed to be withing .001 of spec. (measured using digital caliper)
 
1. Do you use solid carbide drill bits?
2. Are your runout within a thou or so?
I'm guessing you're using a HSS drill that wanders and gets exaggerated due to lack of concentricity.
 
Joey, do you have a link to a suitable boring bar? I'm finding lots in a 1/2" shank, but I think that's too big for the Cuesmith...
 
All good advice.
Check your tailstock offset alignment.
Get a set of pin gauges for measuring hole diameters. They will be helpful for sneaking up on your target bore.
Lubricate the hole before tapping. You can use BLO or wax to reduce tearing.
Run a test with a loose phenolic insert. The phenolic will hold threads better than the maple will.
 
Surffisher
Are you sure your using the correct tap. Radial taps have a lead on them that fit the 5/16" hole so unless your lead was ground off, it shouldn't fit the smaller holes.
 
Michael Webb said:
Surffisher
Are you sure your using the correct tap. Radial taps have a lead on them that fit the 5/16" hole so unless your lead was ground off, it shouldn't fit the smaller holes.
Click to expand...

Thanks everyone, I am going to try boring the holes. The 5/16" bit I have is solid carbide.

I am 99.999% sure I am using the correct tap. I bought it from Unique (https://www.uniqueinc.com/inc/sdetail/ball_screw_tap/2374/16854) and it does screw onto the butt, just not getting the thread thickness correct. I am going to play around more this weekend and see if I can't improve.
 
When you say that the threads don't 'seem' deep enough, is it possible they actually are? Does the pin have wigle room when you screw the shaft half way down? Try a test dowel, drilled to 5/16 then tap it and then on a bandsaw, cut it down the middle lengthwise. Place the joint pin in one of the halves and check the fit. This is the only real world way to verify the thread depth. Please post a picture of the result.
As for a small boring bar....here you go...... Small Boring bar
Minimum hole size is .180 and max depth is 1.5"
 
surffisher2a said:
Thanks everyone, I am going to try boring the holes. The 5/16" bit I have is solid carbide.

I am 99.999% sure I am using the correct tap. I bought it from Unique (https://www.uniqueinc.com/inc/sdetail/ball_screw_tap/2374/16854) and it does screw onto the butt, just not getting the thread thickness correct. I am going to play around more this weekend and see if I can't improve.
Click to expand...

How are you measuring your thread depth / thickness? Just eyeballing it?

It's also possible the radial pin on your butt is non-standard.
 
Linen phenolic inserts are nasty to the taps .
They better be oiled and you back out at least 3 times before hitting bottom .
That tap will get dull really fast on phenolic inserts .
 
www.cuefits.com

Diamand Tip Boring Bar - Varies Diameter in Option

PCD diamand is very hard material, can make precision cut on Non ferrous metal( like Aluminum, Brass), NO-METAL material(wood, plastic, resin etc). and parts will get very smooth cutting surface. DO NOT USE on ferrous metals, it will have chemical reaction between the PCD tip and mat
www.cuefits.com www.cuefits.com
Been using these for a while.
 
surffisher2a said:
Thanks everyone, I am going to try boring the holes. The 5/16" bit I have is solid carbide.

I am 99.999% sure I am using the correct tap. I bought it from Unique (https://www.uniqueinc.com/inc/sdetail/ball_screw_tap/2374/16854) and it does screw onto the butt, just not getting the thread thickness correct. I am going to play around more this weekend and see if I can't improve.
Click to expand...
The original instructions also suggested using a 5/16" reamer. It helps.
I have original taps from uni loc. Haven't tried Unique products version.
 
surffisher2a said:
Thanks everyone, I am going to try boring the holes. The 5/16" bit I have is solid carbide.

I am 99.999% sure I am using the correct tap. I bought it from Unique (https://www.uniqueinc.com/inc/sdetail/ball_screw_tap/2374/16854) and it does screw onto the butt, just not getting the thread thickness correct. I am going to play around more this weekend and see if I can't improve.
Click to expand...
That is the Ball Screw tap.

Uniloc radial is different.

Spend the $175 and you will be set. If I am wrong and the $60 model works out, let me know.
 
CuesDirectly said:
That is the Ball Screw tap.

Uniloc radial is different.

Spend the $175 and you will be set. If I am wrong and the $60 model works out, let me know.
Click to expand...
The ball screw tap is an "almost" identical clone of the uni-loc version of radial. Even with uni-loc radial's there is some variation between them (they have 3 different ones with slightly different tolerances to them).

I don't do this for a living and don't plan to do many taps. Mainly doing this one just as a learning process, so the 60 dollar clone tap should work fine for me. I already tested it on an old junk shaft and it fit on the radial pin that I am tapping this shaft for. I just though the threads looked too shallow. From a practical standpoint it works, its just that I am a perfectionist and I want my work to be as perfect as can be. Plus i am learning a lot by going the extra step.

I do really appreciate all the suggestions I got. I did order a solid carbide 5/16 dtill bit (mine was only carbide tipped). When I get that new bit I am going to give it another try using the help i got from everyone on here, esp lubricating the tap...... I wasn't doing that before.
 
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