# Extra Large Fly Cutters



## Izzy (Oct 5, 2016)

Alright guys as some of you may know I recently got a Bridgeport! One of the operations I plan on doing with the machine is resurfacing automotive cylinder heads, (4 cyl would be the biggest size I would be doing) that being said I need a fly cutter that will do the job, large enough to cut the whole surface in one foul swoop but also has to leave a nice clean surface for sealing. I've been looking at 2 different cutters 
1) suburban tools extra large fly cutter 
2) the pinnacle fly cutter
My question is out of these 2 cutters which would you think would work the best and leave the best surface finish? There is a link to both tools below
https://www.subtool.com/st/fcs_fly_cutter_sets.html
http://www.pinnacleflycutter.com


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## chips&more (Oct 5, 2016)

First off how long is your BP table? And how long is the biggest head. And what diameter fly cutter are you planning to use? I personally, just got an eye opener when I went to try and cut a 24” long piece on a 48” table. You want to make a complete pass over the head from start to finish in X direction only. Check and see if you can…Dave


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## Tony Wells (Oct 5, 2016)

Be careful. A smooth finish is not always what is spec'd. Do your research from factory sources. Head sealing has come a long way in the last few years, with some gaskets having 7 layers. Mainly this is seen on aluminum heads on cast iron blocks, but you never know. It's definitely possible to have one too smooth. 

That said, I'd opt for a real milling cutter, even on a bp type mill. You won't be hogging, but it will make a real diffirence in your finish. You can use inserts that will equal the factory finish (Honda heads use a diamond inserted cutter with about 80 inserts,, iirc. They get about a million heads per set of inserts. But finish control is paramount for success. Do your homework. I did auto machining for a while, and learned the hard way about a few things.


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## Izzy (Oct 5, 2016)

What do you mean real milling cutter? :S Both of these cutters are designed for automotive resurfacing. I know about RA for surface sealing I wasn't really asking about that I'd like to know which tool y'all think are better as far as tool deflection, surface finish and flatness goes?
That being said I have a Bridgeport series 2. 11x58 table I'll be checking too see how flat my entire table is before doing anything.


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## Uglydog (Oct 5, 2016)

If you wanted to, you could make your own fly cutter.

Edit: I followed your link. That's a huge cutter.
Be sure that she is balanced, and that you can get the correct speed for the cutter and material.

Daryl
MN


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## Izzy (Oct 5, 2016)

I don't have a lathe and I'm kinda just starting out the whole machining business I'm a mechanic by trade and I got lucky on the purchase of the machine and want to put it to good use. I've just heard that fly cutters tend to dig into the workpiece over large diameters leaving very slight incline, both cutters are made specifically for cylinder head re-surfacing but which would be better over all I dont know and is what I'm trying to find out


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## jpfabricator (Oct 5, 2016)

The Pinnacle looks nice and beefy, i.e. less chatter. Plus the indexing fixtures to boot. 

Sent from somwhere in east Texas by Jake!


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## Tony Wells (Oct 5, 2016)

Given those two options, the Pinnacle would be my choice. I like the hefty construction, and the ability to position the cutters on different radii for best capability, lengthwise. This may give you the edge on cutting longer heads. It's best not to cross-feed off the head when you run tout of travel if you can help it.


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## Izzy (Oct 5, 2016)

Both have indexable cutters and both have adjustable radii, the suburban tool cutter has the biggest radius @ a whooping 5"-19"!


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## TOOLMASTER (Oct 5, 2016)

..........


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## Izzy (Oct 5, 2016)

Lol I've been leaning towards the pinnacle cutter aswell seems more balanced to Me as you don't have a giant bar swinging around but the price and max diameter of the suburban tool is a big bonus too hmmm.....


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## Tony Wells (Oct 5, 2016)

Bear in mind the larger the swing, the more travel is required to clear the workpiece without feeding across it. Using a 19" swing would eat up 38" of travel.


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## Izzy (Oct 5, 2016)

This is true, I wouldn't be using a 19" diameter anyways just cool that it goes that big! I believe my machine has a 30" travel on the x-axis....


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## Tony Wells (Oct 5, 2016)

19" is a lot for a bp type mill anyway. Unless you are cutting dust. In head work, I can't see the need for that much swing, but I agree, that makes it a nice capable cutter. And if you didn't have a problem feeding off the work in cross feed, use it. The Pinnacle, to me, looks better balanced than the Suburban. No doubt the Suburban is a quality tool, and would probably do the job, but the look and the way I sense it would feel, the Pinnacle would be my choice.


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## Izzy (Oct 6, 2016)

I agree, glad I'm not the only one, the way I see it is the suburban fly cutter is just an all around good fly cutter, probably won't need any others with that kind of range! And the pinnacle seems like it's custom built just for heads and 11'' still clears my entire table. As far as price goes would the suburban tool be a better bang for your buck? Might only ever use it on a few heads for personal builds and such.


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## Tony Wells (Oct 6, 2016)

Well, there is a substantial difference in price, and like you said, the Pinnacle seems to be purpose built whereas the Suburban is a general purpose tool. Most of the time, a dedicated design is better, and obviously there is more meat in the Pinnacle. So there is some justification for the extra expense. If it were a decision based on commercial use in a head shop, the Pinnacle would be the better deal, I'm thinking. Might be a little harder to justify for just a few heads. That part only you can decide. I think we've agreed the Pinnacle is a better tool, so you just have to decide whether to spend that much or back away and settle for a gp fly cutter.


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