cpmech425
Member
I can not get this to work! I have read that it is close enough to work but not for me. I tried drilling 7mm ,9/32 and 7.5mm. All to tight. Anyone make this work or should I order the correct tap? Thanks
m7.5x.5 tap for JOWO #6 nib
- Thread starter cpmech425
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dschem
Member
hokie
Member
Do you recall when you bought your tap or where you bought it from? I had a similar issue with a housing tap I got from a group buy here and it turned out the organizer had given Tapco specifications that did not allow enough tolerance in the thread. See the discussion here about the problem with Bock housing taps: https://www.penturners.org/threads/...6-bock-6-does-yours-work.172169/#post-2139073
ffkappele
Member
Turner's Warehouse sells a Jowo#6 tap. I went with the Bock nibs and got my tap from Beaufort. But Turners Warehouse is solid and should get you what you need. https://www.turnerswarehouse.com/products/m13?variant=39342957035603
duncsuss
Member
As @dschem said, there are multiple steps to drilling the section to receive a JoWo #6 feed & nib housing. Here's what I do, using letter size drills:
1. drill S to depth 2.5mm (for the flange around the nib end)
2. drill M for a further 11mm (to a total depth of 13.5mm)
3. drill I for a further 7mm (to a total depth of 20.5mm) << this is the part that gets threaded by the M7.4 or M7.5 x 0.5 tap
The cartridge/converter typically requires 0.250" (which is letter drill E) in hard plastics, I use letter drills S/N/J and F in ebonite which tends to "close up" after the drill is removed. Sometimes I drill it as step 4, prior to tapping the threads. Other times I do it after tapping, or even from the opposite end of the section (through the tenon).
I got one of the Bock #6 taps that didn't work, it was because Bock used a different standard thread shape specification. JoWo use the normal one: Standards Code D4 versus D20, if I remember correctly. I'm not a machinist so it meant nothing to me, other than the tap didn't work unless I chased the threads on the Bock #6 housing with a matching die.
Oh - another thing: sometimes the housings are slightly oval instead of round, or have molding ridges. That can be a problem that requires a larger drill size in place of letter M at step 2.
1. drill S to depth 2.5mm (for the flange around the nib end)
2. drill M for a further 11mm (to a total depth of 13.5mm)
3. drill I for a further 7mm (to a total depth of 20.5mm) << this is the part that gets threaded by the M7.4 or M7.5 x 0.5 tap
The cartridge/converter typically requires 0.250" (which is letter drill E) in hard plastics, I use letter drills S/N/J and F in ebonite which tends to "close up" after the drill is removed. Sometimes I drill it as step 4, prior to tapping the threads. Other times I do it after tapping, or even from the opposite end of the section (through the tenon).
I got one of the Bock #6 taps that didn't work, it was because Bock used a different standard thread shape specification. JoWo use the normal one: Standards Code D4 versus D20, if I remember correctly. I'm not a machinist so it meant nothing to me, other than the tap didn't work unless I chased the threads on the Bock #6 housing with a matching die.
Oh - another thing: sometimes the housings are slightly oval instead of round, or have molding ridges. That can be a problem that requires a larger drill size in place of letter M at step 2.
rherrell
Member
For my J6 step drill I grind the step for the threads at .272" (6.9mm). I've sold hundreds of them and haven't heard of your problem. I would recommend getting the correct tap from Turners Warehouse, it's made in the USA.
cpmech425
Member
Just ordered the correct tap from Turners Warehouse.