When at first you don't succeed - Kurt vise-broken tap

[Janderso]

Hey all,
Happy Christmas!!

It seems like a great idea to follow the popular idea, of tapping the Kurt vise jaw retaining bolts to hold tooling.

The first one came off without a hitch, the second one has a broken Irwin plug tap stuck in it. It's going to stay that way.
A fellow machinist suggested using a tap drill size a bit larger due to the high quality of the Kurt retaining bolts.
10-32 calls for a #21 tap drill size. I went with a #20.
I have found the quality spiral taps do the job with much less resistance. I didn't have that size.
The cheap Irwin brand gave me plenty of resistance, I was careful, it still broke.

This is my remedy. New bolts from McMaster and a quality 10-32 spiral tap also from McMaster.
I'm sharing this with you because it's a great advantage to have the ability to fasten precision angle devises, V blocks etc.
And, discovering spiral flute taps really helps me avoid breaking taps, they cut much easier and the chips come up and out of a blind hole.

 

[tjb]

It seems like a great idea to follow the popular idea, of tapping the Kurt vise jaw retaining bolts to hold tooling.

That does sound like a great idea, but I've not seen anything on it. What tooling would you mount to it? Any threads here on HM? Youtube?

Regards

 

[tjb]

I'm sharing this with you because it's a great advantage to have the ability to fasten precision angle devises, V blocks etc.

I was too focused on your broken tap to see this part of your post. Any photos of this in action?

 

[projectnut]

Quality spiral flute taps have been a lifesaver on more than 1 occasion. I was introduced to them back in the 1980's when working in a company machine shop. At the time I only used them on rare occasions, and wasn't all that trusting of the relieved shank. It seemed as though the narrower shank would result in poorer strength and the tap would be more prone to breaking in tough material.

I avoided using them on a regular basis until about 10 years ago. I had a job with over 1,000 blind holes, and was having trouble threading to the bottom. Even with a standard modified bottoming tap I had to back out several times to clear chips. It was time consuming and ultra boring.

It was suggested I switch to the spiral flute design and do each hole in 1 pass. I tried it and was sold on their ability to clear chips, and thread to within 1 revolution of the bottom of the hole. The best part is that I only needed a couple taps to complete the job. I probably could have gotten by with 1, but I wasn't in the mood to have a tap break and go through the hassle of removing it.

At the time I stocked up on the most popular sizes with an average cost of less than $3.00 per unit. I had to replenish a few sizes lately and couldn't believe the price increase. Most sizes now cost in the neighborhood of $10.00 to $20.00 per unit. I do keep my eyes open for them and occasionally find some in the $4.00 to $6.00 range. I've seen lots of brands out there, but so far have kept with GTD-Widia, Hi-Pro, Regal, Greenfield, and YG-1.

 

[Janderso]

Outside screwball did a segment on it. at about 5 minutes in.
Check it out.

 

[metric_taper]

I've been burned by unknown quality taps as well in the past.
This mod seems like a good thing to have for a setup option.
I would put the hardened socket head screws in my heat treat furnace and anneal them. I do that with heat treated tool steel. I don't know what the annealing schedule would be for these screws. But I doubt if they are air hardening, so probably just bring them up to red heat and let them cool down with power off to the furnace over night.
I don't see this hardness being needed, but I may be wrong. These screws are not in shear, and only hold the jaws in place, when clamping a part.

 

[Janderso]

I would put the hardened socket head screws in my heat treat furnace and anneal them

That's probably a sensible idea. I don't have any confidence I could return them to the proper temper.
Now that I have a quality spiral flute tap, I do have the confidence this will be a no brainer.
I use my coaxial indicator to find dead center, drill and use a tap guide for proper alignment.

 

[PT Doc]

As soon as I heard Irwin, carbon steel came to mind. I think that’s the problem.

 

[Chewy]

Irwin is a hardware store brand for homeowners. Buy your taps from KBC, Travers, McMaster, MSC. I have only been using the house brand and have not had any problems. I have seen several references to tapping the holding bolts from reputable You Tubers. It allows for some fancy setups made easier. Planning to do this myself this winter. First choice is spiral flute taper tap and lots of blowing out holes and threads. Just drew up Vee blocks that will require about 30 holes, 10-32 about 1/2" deep in CRS or mystery steel. At this time only planning on 1 or 2 taps for all the holes.

 

[tjb]

Outside screwball did a segment on it. at about 5 minutes in.
Check it out.

Thanks, Jeff.

Very interesting. That's now on the agenda.

Regards,
Terry