Un-Oops That Cross Threaded Spark Plug Hole
By Eric Dykstra
It can happen to the best of us: one moment of inattention results in a cross-threaded spark plug hole. You can either install a helicoil and hope for the best, or send it out to have the whole shebang re-tapped. Now you have another option. The Back-Tap can fix that cross-threaded hole from the inside — without pulling the head.
The Back-Tap is a tap with expandable threads and a mandrel to catch errant metal shards. Apply a dab of grease to the mandrel, then place the device in the hole past the damaged threads. As you back it out, the cutters expand out to engage the undamaged threads, then gently reshape the damaged ones. The greased mandrel keeps metal filings from ending up in the cylinder.
The result: a task that could potentially take days and cost hundreds of dollars is done in minutes for less than a hundred bucks.
MAC offers a three-piece kit that includes a 10mm, 12mm, and 14mm Back-Tap for $90. You can buy Individual taps from various sources for about $50 each.
Back-Tap [Official Page]
Back-Tap Kit [MacTools.com]
Street Price [Google Products]
Via Amazon [What's this?]





















November 15th, 2007 at 12:33 am
Actually, the best deal on this tool can be found in the PowerBuilt Tool line by Alltrade.
http://www.alltradetools.com/index.html/screen/model_detail/category_id/192/display_id/id451c07679c1d47.05217653/product_id/2909
November 15th, 2007 at 1:44 am
These taps are not usually used for a cross threaded plug, but from damage done when removing a seized plug in an aluminum head.
November 15th, 2007 at 7:18 am
This is nothing new and made by KABA Tools of Taiwan for Mac. It’s also available though Mac’s new parent company, PROTO and several online tool stores. When the CEO of Mac left in April, PROTO took over the reins so much of what is now being made in the PROTO/Dallas plant and out of China and Taiwan, is all the same – just stamped different and prices higher for the truck guys.
Now if I could just find a Mac distributor to replace all my broken tools, I’d be happy. All three distributors folded shop in my area in the last two months and Mac HQ is unwilling to help. According to them, PROTO/Stanley is looking to dissolve the company over the next three years.
December 15th, 2007 at 8:00 pm
Hey guys,
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The best soft to PC-where to buy, join site & other tipe to do a home online business.
With best regards.
May 10th, 2009 at 6:52 pm
i am trying to locate a mac tool dealer in the cleburne texas area
any information will be greatly appreciated
thank you
ernie mccuistian
817-550-3914