spot face Q / advice....

[hardtimes]

Any you guys do your own 'spot facing' of head bolt/nut surfaces ?
Any recommendation for someone who wants to do such work, i.e.- don't; yeah doable; here's what you need and how; precautions , etc

Usually, I take parts to machinist and spend enough in time/transport/$ , that I coulda bought tool stuff and tried to help myself. I like doing whatever is doable for my hobby

[deuce_roadster]

I've never seen a head that needed that. I use hardened washers on aluminum heads and my cast iron ones appear fine.

[Jim in Wisconsin]

I don't know whether heads needs this done or not, but in general spot facers come in different diameters to match the washer or nut, and have a replacable pilot to keep them centered in the hole. They would be run fairly slow, and just deep enough to clean up unless a certain dimension is called for.

[hardtimes]

Originally Posted by deuce_roadster

I've never seen a head that needed that. I use hardened washers on aluminum heads and my cast iron ones appear fine.

Some of the older heads have suffered thru a lot of (mis)use and abuse. I do not like to torque down a head nut against an uneven surface, no matter how slightly uneven. I also use hard washers under nuts on alum, but by the time I get the head...usually some work needed to make nice as some seem not to know about washer use .

[JSeery]

Unless this is performed with precession there is chance of causing much more damage than you are solving. The machined surface needs to be perpendicular to the center line of the head bolt/stud.

[Ol' Ron]

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Yes I have a spot facing Kit, Includs severl sizes and arbors, plus I made some. You can get one from Enco.

[hardtimes]

Originally Posted by Ol' Ron

Yes I have a spot facing Kit, Includs severl sizes and arbors, plus I made some. You can get one from Enco.

Hey Ol'Ron,
Thanks much ! I will google Enco. Measured my area needing a 'light' clean up (spot face). It is 1inch diam.

[hardtimes]

Originally Posted by Jim in Wisconsin

I don't know whether heads needs this done or not, but in general spot facers come in different diameters to match the washer or nut, and have a replacable pilot to keep them centered in the hole. They would be run fairly slow, and just deep enough to clean up unless a certain dimension is called for.

Hey Jim,
Yeah, this is the help/info that I need, thanks !
The plug hole is 14 mm (I/2") so will search for pilot in that diam.
Just need to make surfaces flat and it won't take much..and do slow.

[JWL]

There has already been some good info given. I will only add that I use a light spray of WD-40 just before the cutter makes contact with the part. The improvement in cutting and surface finish is remarkable. Of course the table and spindle should be nearly perfectly perpendicular and the pilot needs to be a good fit at the dilled holes.

[Mart]

Hang on, you were talking about spot facing the head stud faces then announced you were going to buy one for spark plugs??

The head stud holes (you should check this) are oversize on 7/16", I remember a 29/64" drill just going in nicely. 29/64" is smaller than 1/2".

You need a spot face tool with a 7/16 or 29/64 pilot and a flat face suitable for the typical washer diameter you intend to use.

There might be a metric size available but you need to do the digging.

Mart.

[GOSFAST]

Originally Posted by hardtimes

Any you guys do your own 'spot facing' of head bolt/nut surfaces ?
Any recommendation for someone who wants to do such work, i.e.- don't; yeah doable; here's what you need and how; precautions , etc

Usually, I take parts to machinist and spend enough in time/transport/$ , that I coulda bought tool stuff and tried to help myself. I like doing whatever is doable for my hobby

Spotfacing ALL the head bolts holes is an excellent idea, one we do on every used head we work with, no matter the mfr. This is all done a dedicated cylinder head machine, no room for error.

It does require a reasonably "slow" speed for a decent finish along with a nice sharp cutter and a nice "snug" pilot. We run a drill through all the holes first so the pilot has a clean hole.

Would also recommend using head bolt washers on ass'y. We've supplied many up here with "custom" washers, barely visible when installed (photos below).

Originally Posted by Ol' Ron

Yes I have a spot facing Kit, Includs severl sizes and arbors, plus I made some. You can get one from Enco.

Hi Ron, "Enco" is gone, they closed down recently. They were always owned by MSC-Industrial, but I guess MSC just wanted to condense the operation??

Thanks, Gary in N.Y.

P.S. Here's a couple shots of the washers we use mounted on some OEM bolts. These washers work well with either Cast or aluminum heads, and are chamfered on one side.

[Ol' Ron]

POOP! It seems like all the inexpensive stuff us builders need are going out of business. Afew years back there were 3 veru good machine shops with in 25 miles and five in 50 miles. now it's down to one in each. I have an old Enco Mill that's still making parts. Feel sorry for the new comer, he has less to choose from.

[Fordors]

Keep in mind that the spotface cutters called reverse counterbores sold by MCS are for CCW rotation and take a special arbor used on a radial drillpress, or a spotface table. To spotface in a conventional drillpress you want counterbore tools that are used with interchangeable pilots. Counterbores will be made and sharpened for CW rotation.
When you consider the cost of the necessary cutter and pilot it probably makes sense to just have it done in a machine shop. I can't imagine a pair of flathead heads taking an hour, probably less.

[Andy]

I am a savage I guess. I had an old pair of heads that really needed spotfacing. I took a piece of bar and drilled a 7/16" hole thru the bar. I then turned the bar to the dia needed. I tack welded a piece of 7/16 bar in the cutter after grinding some flukes on it. It heads are probably is not perfect but are light years better than they were. They look extreamly nice to me. You are only trying to cut aluminum.

[hardtimes]

Originally Posted by Andy

I am a savage I guess. I had an old pair of heads that really needed spotfacing. I took a piece of bar and drilled a 7/16" hole thru the bar. I then turned the bar to the dia needed. I tack welded a piece of 7/16 bar in the cutter after grinding some flukes on it. It heads are probably is not perfect but are light years better than they were. They look extreamly nice to me. You are only trying to cut aluminum.

Hey Andy,
You are sure enough some kind of savage..lol With machining tools and welder to 'make' tools,,wow ! Some day you want to meet / see a real savage, come by and look around ! Still recouping from major lf shoulder surgery from carrying a short blk around 'shop'. A bud referred to my 'savage' lair/shed.... as a 'shop'...made me feel good, so use it now

[hardtimes]

Originally Posted by Fordors

Keep in mind that the spotface cutters called reverse counterbores sold by MCS are for CCW rotation and take a special arbor used on a radial drillpress, or a spotface table. To spotface in a conventional drillpress you want counterbore tools that are used with interchangeable pilots. Counterbores will be made and sharpened for CW rotation.
When you consider the cost of the necessary cutter and pilot it probably makes sense to just have it done in a machine shop. I can't imagine a pair of flathead heads taking an hour, probably less.

Hey Fordors,
Thanks , for spot on advice and info !
I was wondering about 'reverse counterbore' meaning and went to Enco and found out exactly what you are saying. I figure that I need 1/2" pilot and 1" or less diam cutter. Hm, couple hundred or so $ from Enco ..yikes !

I use both alum and cast iron antique heads, so some need restoring. Yeah, I agree that a machinist is your friend at these times of need, or use as is, if you don't want to or can't meet the costs.

Question: I've seen some pretty messed up/chewed up spark plug hole surfaces. Do you also touch these up ?

[hardtimes]

Originally Posted by Ol' Ron

POOP! It seems like all the inexpensive stuff us builders need are going out of business. Afew years back there were 3 veru good machine shops with in 25 miles and five in 50 miles. now it's down to one in each. I have an old Enco Mill that's still making parts. Feel sorry for the new comer, he has less to choose from.

Hey Ol' Ron,
I checked out Enco. You already know what I found. Yup, this newby 'machinist' welcomes your empathy.
Your advice is always welcomed and valued

[hardtimes]

Hey Gary,
Do you use 'bolts' on flatheads also ? Nice washers, are they hard steel ?

[rotorwrench]

Some of the late counter bore tooling is Asian made and lacks the quality of the older stuff. Not much more than a three flute drill. I still have an old set that has small sizes up to 1-inch with a pilot set for all the more common sizes. These sets are harder to find now and expensive if you do. I've had to make several special size ones when you need a tighter fit. There are outfits that still custom make nice stuff for manufacturing but they are way expensive. If you have a good pilot fit, you can use many of them with a hand drill as long as you are careful and don't hogg away with them.

[Mart]

Originally Posted by hardtimes

I figure that I need 1/2" pilot....

How can you use a 1/2" pilot? the hole is smaller than 1/2".

I did say this in a previous post, but you appear not to have taken the info in.

mart.