Hot Water Circuit in Harman Hand Fired

I been heating domestic hot water for bout 8 years with a section of straight ¾" tubing x .065" wall. I made this in 2006-2007 with a tube bender and Parker A-Lok SS fittings. I discovered yesterday it has failed. It has a stress crack. I will remove it. Little crusty too but it served me well. If anything, my hot water was too hot. It was too long.
I have this hot water coil I can install. It is the Harman factory part. But I do not have any additional mounting parts for it.
It is ¾" npt without a taper.
I found these locking nuts on Amazon. 304SS x ¾" npt. I am wondering if I should go with a total of 8 or if 4 will be enough?
Does anyone have one of these Harman coils installed? What parts came with the kit? I am thinking SS washers or heat resistant washers? I want to be sure I install it soundly as possible so it stays put in the stove.

Lucky for me my existing ¾" penetrations are perfectly in line with what the Harman part will use. I just need to up the hole from ¾" to 1.05". This could probe to be more difficult than it sounds as a hole saw may not stay squared and a 1" drill bit will be costly.

do you have any freinds that would let you borrow a bit,it's a shame to buy one for 2 holes.What about a rattail file/chainsaw file or a reamer,their not so costly.Could you just bend another shorter 3/4" pipe and sell the Harman coil.

Dennis wrote:do you have any freinds that would let you borrow a bit,it's a shame to buy one for 2 holes.What about a rattail file/chainsaw file or a reamer,their not so costly.Could you just bend another shorter 3/4" pipe and sell the Harman coil.

Do you have a 1" bit I can wear out?

A step down bit might be my best bet. About $30-$40

I don't have one,but have know several that I can borrow for you,if needed.It's rare you wear one out,maybe make it dull, then just sharpen it

Cap wrote: I just need to up the hole from ¾" to 1.05". This could probe to be more difficult than it sounds as a hole saw may not stay squared and a 1" drill bit will be costly.

Can you wedge a wooden dowel in the 3/4" hole and then use the hole saw?

Cap I believe we have an extra set of parts for that coil. Nuts washers and gaskets. Give me a shout on Monday. Dave

Dennis wrote:I don't have one,but have know several that I can borrow for you,if needed.It's rare you wear one out,maybe make it dull, then just sharpen it

your not going to harm the bit (they should be sharpened all the time anyways)... maybe your wrist when she makes the final brake through and the drill takes your arm for a spin
If you cant find one to borrow locally i'll mail one to you (But a one inch bit should pretty easy to borrow from just about anyone in your neighborhood or town).

They have hole saws that can accept a larger pilot bit...
I like the bung idea but make it a hardwood...

dcrane wrote:

Dennis wrote:I don't have one,but have know several that I can borrow for you,if needed.It's rare you wear one out,maybe make it dull, then just sharpen it

your not going to harm the bit (they should be sharpened all the time anyways)... maybe your wrist when she makes the final brake through and the drill takes your arm for a spin
If you cant find one to borrow locally i'll mail one to you (But a one inch bit should pretty easy to borrow from just about anyone in your neighborhood or town).

Cool, I'll take you up on your offer. I have no neighbors with tools. In addition, I never learned how to sharpen a drill bit. I tried a few times but the bit never seems to cut better. I tried a wheel and/or a file. And I use oil and drill slow.

Let me know what you can do.
Thanks a bunch.

Flyer5 wrote:Cap I believe we have an extra set of parts for that coil. Nuts washers and gaskets. Give me a shout on Monday. Dave

Thanks Dave, I will call you Monday afternoon. Is your number on the website? I'll check.
Thanks a bunch.

Cap wrote:

Flyer5 wrote:Cap I believe we have an extra set of parts for that coil. Nuts washers and gaskets. Give me a shout on Monday. Dave

Thanks Dave, I will call you Monday afternoon. Is your number on the website? I'll check.
Thanks a bunch.

[Phone Number Removed] Just in case.

Cap,I didn't get a 1" drill bit,but I did get a 3/4" to 1" reamer.You will need a 3/4" drill and eat your wheatie and get ready to wrestle the drill.PM me when you get a chance

Dennis wrote:Cap,I didn't get a 1" drill bit,but I did get a 3/4" to 1" reamer.You will need a 3/4" drill and eat your wheatie and get ready to wrestle the drill.PM me when you get a chance

Dennis, I appreciate the offer but I do not have a ¾" electric drill. I have a ½" electric drill. I may just have to buy a step bit. They work really nice when sharp or new.

I would use a step drill if the metal is thinner than 3/16" if its much thicker than the steps then the hole has to be drilled from bothe sides or else you will be cutting on more than one step and that risks braking the bit, however they are a lot more forgiving when they break through.

just start with a small bit and work up ... insure you spray some wd40 on them and let the piece cool down in between drillings