I made a bolt knob the other day out of 303 stainless but I could not get the tap to make more than about 4 threads inside it before it got really tight and eventually broke off in the knob. The initial hole was drilled to just .0005 less than the max diameter for the <span style="text-decoration: line-through">5/8</span> 5/16x18 tap that I was using and I was going slowly and backing it out and making sure I didn't have too much material built up inside. The tap was just a $5 one from the local hardware store. Are you guys that are making custom knobs using a higher-end tap?
Gunsmithing Good Tap for Threads on Custom Bolt Knobs
- Thread starter nauta
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Re: Good Tap for Threads on Custom Bolt Knobs
You definitely want a better tap sounds like a cheap tap is your problem. I assume your using a cutting fluid of some kind that will help also. I buy most of my stuff from here MSC Metal Working If your bolt knob isn't a through hole you will probably want a bottoming tap.
All the bolt knobs I have made have been aluminum. I haven't seen a need myself to use stainless.
You definitely want a better tap sounds like a cheap tap is your problem. I assume your using a cutting fluid of some kind that will help also. I buy most of my stuff from here MSC Metal Working If your bolt knob isn't a through hole you will probably want a bottoming tap.
All the bolt knobs I have made have been aluminum. I haven't seen a need myself to use stainless.
Re: Good Tap for Threads on Custom Bolt Knobs
Guhring.
After running a machine shop for 10 years, I won't use anything else when it comes to drills or taps.
If cutting it by hand, Tap magic works pretty well, I know its made in the USA so should be easier to get there than it is here.
Guhring.
After running a machine shop for 10 years, I won't use anything else when it comes to drills or taps.
If cutting it by hand, Tap magic works pretty well, I know its made in the USA so should be easier to get there than it is here.
Re: Good Tap for Threads on Custom Bolt Knobs
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nauta</div><div class="ubbcode-body">I made a bolt knob the other day out of 303 stainless but I could not get the tap to make more than about 4 threads inside it before it got really tight and eventually broke off in the knob. The initial hole was drilled to <span style="font-weight: bold"> <span style="color: #FF6600">just .0005 less</span></span> than the max diameter for the<span style="font-weight: bold"> <span style="color: #FF0000">5/8x18 tap</span> </span>that I was using and I was going slowly and backing it out and making sure I didn't have too much material built up inside. The tap was just a $5 one from the local hardware store. Are you guys that are making custom knobs using a higher-end tap? </div></div>
You did not mention what type of tap you were using. Was it a taper, plug or bottom tap? What size tap drill did you use for the 5/8x18, which by the way isnt the standard thread used in most knobs? Maybe a typo on your part? The most common knobs use 5/16x24tpi. Right now I have a Cleavland HHS tap that probably has 45 knobs both stainless and aluminum on it. Using TapMagic and the recomended letter "I" drill bit for 5/16x24tpi it still producing chips.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nauta</div><div class="ubbcode-body">I made a bolt knob the other day out of 303 stainless but I could not get the tap to make more than about 4 threads inside it before it got really tight and eventually broke off in the knob. The initial hole was drilled to <span style="font-weight: bold"> <span style="color: #FF6600">just .0005 less</span></span> than the max diameter for the<span style="font-weight: bold"> <span style="color: #FF0000">5/8x18 tap</span> </span>that I was using and I was going slowly and backing it out and making sure I didn't have too much material built up inside. The tap was just a $5 one from the local hardware store. Are you guys that are making custom knobs using a higher-end tap? </div></div>
You did not mention what type of tap you were using. Was it a taper, plug or bottom tap? What size tap drill did you use for the 5/8x18, which by the way isnt the standard thread used in most knobs? Maybe a typo on your part? The most common knobs use 5/16x24tpi. Right now I have a Cleavland HHS tap that probably has 45 knobs both stainless and aluminum on it. Using TapMagic and the recomended letter "I" drill bit for 5/16x24tpi it still producing chips.
Re: Good Tap for Threads on Custom Bolt Knobs
Guhring.Guhring.Guhring.Guhring.
The Krauts certainly have their shit together with these taps.
Great stuff. I buy them almost exclusively.
Also remember: It's a bolt knob. It's not a spar bolt to a stealth bomber. Punch the hole a little oversize. It may go on a little loose, but lock tite will solve that. Stainless is gummy/abrasive stuff and loves to send taps home crying to momma like a little biche.
You never mentioned what grade SS your using. 303 is prolly the most forgiving. If it's 304 I'd suggest leaving it alone and getting a different piece of material.
A little hydraulic oil works great as a tapping fluid for SS also.
Good luck!
C.
Guhring.Guhring.Guhring.Guhring.
The Krauts certainly have their shit together with these taps.
Great stuff. I buy them almost exclusively.
Also remember: It's a bolt knob. It's not a spar bolt to a stealth bomber. Punch the hole a little oversize. It may go on a little loose, but lock tite will solve that. Stainless is gummy/abrasive stuff and loves to send taps home crying to momma like a little biche.
You never mentioned what grade SS your using. 303 is prolly the most forgiving. If it's 304 I'd suggest leaving it alone and getting a different piece of material.
A little hydraulic oil works great as a tapping fluid for SS also.
Good luck!
C.
Re: Good Tap for Threads on Custom Bolt Knobs
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: el gordo2</div><div class="ubbcode-body">
You did not mention what type of tap you were using. Was it a taper, plug or bottom tap? What size tap drill did you use for the 5/8x18, which by the way isnt the standard thread used in most knobs? Maybe a typo on your part? The most common knobs use 5/16x24tpi. Right now I have a Cleavland HHS tap that probably has 45 knobs both stainless and aluminum on it. Using TapMagic and the recomended letter "I" drill bit for 5/16x24tpi it still producing chips. </div></div>
It was a taper tap and you're right, I meant 5/16. I was using 18TPI because that's all I could find at the store and I'm threading the bolt myself to match. I was using oil but maybe I should try the TapMagic. I will look for a Guhring or Cleveland tap, also. Thanks, guys.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: el gordo2</div><div class="ubbcode-body">
You did not mention what type of tap you were using. Was it a taper, plug or bottom tap? What size tap drill did you use for the 5/8x18, which by the way isnt the standard thread used in most knobs? Maybe a typo on your part? The most common knobs use 5/16x24tpi. Right now I have a Cleavland HHS tap that probably has 45 knobs both stainless and aluminum on it. Using TapMagic and the recomended letter "I" drill bit for 5/16x24tpi it still producing chips. </div></div>
It was a taper tap and you're right, I meant 5/16. I was using 18TPI because that's all I could find at the store and I'm threading the bolt myself to match. I was using oil but maybe I should try the TapMagic. I will look for a Guhring or Cleveland tap, also. Thanks, guys.
Re: Good Tap for Threads on Custom Bolt Knobs
In the first place, forget hardware store taps - they are WORTHLESS.
Use the recommended tap drill size - on a job like this one, nothing is to be gained whatsoever by boring anything else.
The best tap on this job is a spiral flute bottoming tap. Greenfield makes em, get em from MSC. Drill the hole, swap the drill for the tap, and power it in. It'll turn in the chuck when in bottoms, then shift to reverse to back it out, and blow the oil out. There's no chips in the hole, they spiral out on the way in.
In the first place, forget hardware store taps - they are WORTHLESS.
Use the recommended tap drill size - on a job like this one, nothing is to be gained whatsoever by boring anything else.
The best tap on this job is a spiral flute bottoming tap. Greenfield makes em, get em from MSC. Drill the hole, swap the drill for the tap, and power it in. It'll turn in the chuck when in bottoms, then shift to reverse to back it out, and blow the oil out. There's no chips in the hole, they spiral out on the way in.
Re: Good Tap for Threads on Custom Bolt Knobs
Taper tap in a tight blind hole in SS? 4 threads sounds about right. Bigger hole, grind some off the end of that tap, redo and loc-tite the knob. Cheap taps work for one or two holes with tap-magic.
Taper tap in a tight blind hole in SS? 4 threads sounds about right. Bigger hole, grind some off the end of that tap, redo and loc-tite the knob. Cheap taps work for one or two holes with tap-magic.
