Author Topic: Flathead V-8  (Read 170854 times)

Offline petertha

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Re: Flathead V-8
« Reply #255 on: March 10, 2015, 06:31:19 PM »
Thanks George. Re the dial test indicator question, I was wondering about the mounting bracket  & positioning arm gadget where it attaches to your mill spindle arbor? or end mill holder? Sorry for the confusion (but appreciate additional info on the crankshaft + DTI setup itself.)

Back on the custom tool bit, since you are entering the cut straight in, do you have relief in top view (exaggerated orange lines) and/or front view (exaggerated yellow lines)?

Offline gbritnell

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Re: Flathead V-8
« Reply #256 on: March 10, 2015, 08:57:41 PM »
Hi Peter,
I first ground the blank to the thickness of the tip so that I could mike it and keep it parallel. I then ground the rear part of the blade about .025-.030 thinner per side than the tip. I figured this would allow me several sharpenings, or more. I then ground side clearance on the tip only. It tapered from the outer edge down to the bottom of the bit. (.50) I then ground front clearance, about 5 degrees. To split the tip I used a thin cutoff wheel in my Dremel grinder, first just plunging in and then tilting it to put a small amount of relief on the edges. I then lightly broke the outside corners with my bench grinder and finished up putting a nice radius on with a diamond honing stick. The diamond stick was also used to put a small radius on the inside corners although it's not absolutely necessary. The idea is to have the tool narrower than the total width of the cut so that both sides of the tip overlap.
I don't have any clearance on the sides going back from the tips as you have shown. With the space between the cheeks roughed out to size on the mill it's only necessary to round the journal. The tool is rigid enough so that once the journal is to size I can move the crossfeed out, touch the milled wall and then go back to my journal dimension. This will skim any small amount of material from the side.
The front edge of the tool was ground square to the sides to begin with so to set up for cutting I just line up either side of the tool square to the lathe axis and then run the DTI against the tip to verify that it is parallel to the lathe axis.
Here is the link to the build of my inline six cylinder engine. This was a little more complete writeup about the cranks machining and turning.
http://www.modelenginemaker.com/index.php?topic=2295.msg37648#msg37648
In regard to the DTI holder, I went back to the pictures and now I understand what you're asking. It's just a V- type clamp that clamps around my end mill holder. It has reamed holes in the corners with a thumbscrew to tighten the indicator stem. The indicator is mounted to an offset bracket that allows me to swivel it in or out so that I can indicate different diameter holes or bosses when setting up. I will take some pictures this evening and add to this post.
gbritnell
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Offline Art K

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Re: Flathead V-8
« Reply #257 on: March 11, 2015, 01:45:58 AM »
George,
Thank you for the detail in your engine builds. I have thought about various engines I would like to build and think about things like oil passages drilled in the crank and your fixture for drilling the V8 crank isn't something that even occurred to me. It will now, I have all sorts of aluminum in odd shapes that could be used for a fixture. Your tag line at the bottom of the page has always stuck with me "Talent unshared is talent wasted." I have worked with people who thought the opposite, and wouldn't even share the information that was needed to do my job properly. Thanks
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline gbritnell

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Re: Flathead V-8
« Reply #258 on: March 11, 2015, 02:49:56 AM »
Thanks Art.
Peter,
Here's several pictures of the clamp that I made to hold my indicator. Nothing fancy but I can use it even with a cutter in the spindle. I don't have to take anything apart, just clamp and go. The indicator is on it's own swivel connection so I can move it in and out as needed. I originally made the offset swivel so that I could put the indicator in the tailstock chuck and adjust it up and down as needed to check pieces in the chuck.
gbritnell
Talent unshared is talent wasted.

Offline Hugh Currin

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Re: Flathead V-8
« Reply #259 on: March 11, 2015, 03:04:02 AM »
To set it up I first align the edge with my workpiece then using a dial indicator I check the tip for parallelism.

George:

Thanks for all your instruction and guidance. I was using a cut off tool to machine in behind a shoulder today. I found this tip very useful.

Great build, thanks for documenting it with instruction and tips.

Thanks.

Hugh
Hugh

Offline petertha

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Re: Flathead V-8
« Reply #260 on: March 12, 2015, 12:26:16 AM »
Peter, Here's several pictures of the clamp that I made to hold my indicator.gbritnell
Perfect, thanks. Glad I asked!

Offline gbritnell

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Re: Flathead V-8
« Reply #261 on: March 16, 2015, 12:20:30 AM »
With all the major parts machined it's time to start picking away at all the small bits and pieces.
I turned up all the main bearing inserts from bearing bronze rod. They were split and fitted to the crank and block. The caps were drilled for stop pins to keep the inserts from spinning. The inserts were drilled to match the oil passage in the block.
I turned the flywheel from 12L14 steel (4.25 dia.) and drilled and reamed the mounting holes to match the crankshaft.
I turned the blanks for the timing gears, steel for the cam and brass for the crank. The cam gear will be pressed on with no actual way to align it for timing so the crank gear will have 4-.062 key slots, one lined up with a tooth, one lined up between two teeth, one a 1/4 between the root and tip and the last tooth 1/4 on the other side of the root. This will allow me to set the cam timing within 3 crank degrees which will be close enough.
The gears are 32 D.P. and I just happen to have a set of involute cutters that fit the number of teeth I needed.
The teeth were cut on the cam gear and then it was set up on the rotary table to have some slots milled into it.
gbritnell
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Offline ironman123

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Re: Flathead V-8
« Reply #262 on: March 16, 2015, 12:36:18 AM »
Being a Flathead Ford guy, I am loving this thread.  Thank you George for this build. :popcorn: :popcorn: :whoohoo:
Ray
Central Texas

Offline Brendon M

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Re: Flathead V-8
« Reply #263 on: March 18, 2015, 06:49:12 AM »
Hello George

Without the size references in the background, you would think you are looking at the real thing  :ThumbsUp:

...
I turned up all the main bearing inserts from bearing bronze rod. They were split and fitted to the crank and block. The caps were drilled for stop pins to keep the inserts from spinning.
...

Do you have photos of the bearings? One of the things I have not worked out is how to prevent the bearings from spinning.

Thank you :)
Brendon
(This signature intentionally left blank)

Offline gbritnell

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Re: Flathead V-8
« Reply #264 on: March 20, 2015, 06:39:34 PM »
Gentlemen,
The next part or parts are the connecting rods. In the past I have used bronze for my rods and have had good luck both with strength and durability but for this engine I decided to go with steel rods and bronze bearing inserts both for the journals and wrist pin bores.
I started by squaring up some stock and milling it to the proper thickness. To keep track of the rods and caps and as to which cylinder they would go into I stamped identification numbers onto the sides of the stock, taking into account where the future milling would be so that I didn't cut them off. By stamping them at this point I wouldn't have to worry about distorting the caps by banging on them later on.
The next operation was to drill and counter drill each of blanks for the cap screws. I also drilled and reamed for the bearing stop pin.
Talent unshared is talent wasted.

Offline gbritnell

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Re: Flathead V-8
« Reply #265 on: March 20, 2015, 06:47:42 PM »
When I calculated the drilling depths I took into account the width of the saw cut and an additional .04 per side for cleanup. I gave myself a guide line and sawed each of the caps off. The caps and rods were then set up in the mill and to size. The next step was to tap all of the holes 5-40 thread. The caps were then mounted with socket head screws. The clearance holes were drilled .125 so I could use the screws to align the caps to the rods. I snugged up the screws and then clamped each assembly in the vise to make sure that all the surfaces were flush before finally tightening the screws.
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Offline gbritnell

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Re: Flathead V-8
« Reply #266 on: March 20, 2015, 06:53:23 PM »
I set up the stop rod for my mill vise so I could drill and bore each of the rods in the exact same place. Each rod was center drilled at both locations, journal and pin, and then the journal ends were drilled with successively larger drills. The finished size for the journals is .702. This takes into account the thickness of the bearing insert. Each hole was finished with the boring head to make sure that the holes were accurate both in diameter and position.
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Offline gbritnell

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Re: Flathead V-8
« Reply #267 on: March 20, 2015, 07:01:53 PM »
I then drew a guideline on each rod so that I could bandsaw the extra stock off. For all the finishing operations the rods would need to be mounted on a fixture plate. Using a previous plate I put new holes in it to locate the rods. The center hole is tapped 10-24 for the hold down screw. Above this is a counterbored hole, .250 for the pin and .375 for the journal. I then turned up plugs to go into each hole that the rods would locate on. A cap was also turned up that had a flange to match both finished diameters. This would aid in getting close with the end mill while finishing the side profiles.
The rotary table was set up and indicated. The fixture plate was then mounted and the center for the side radius of the rod was picked up.
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Offline gbritnell

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Re: Flathead V-8
« Reply #268 on: March 20, 2015, 07:05:25 PM »
Here are pictures of the rods with the side profiling completed.
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Offline gbritnell

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Re: Flathead V-8
« Reply #269 on: March 20, 2015, 07:07:09 PM »
The final operation with this setup was to flute the rods. Using a .125 end mill with a small corner radius each side of the rods were cut .040 deep.
gbritnell
Talent unshared is talent wasted.

 

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