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Fly cutter for skimming cylinder heads.

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Fly cutter for skimming cylinder heads.

Postby ShaunK » Sat Sep 18, 2010 2:07 pm

I'm looking for a fly cutter to skim cylinder heads with a mill. It is a bridgeport mill. I'm wondering if there is one that is preferred over the others or performs better. Thanks in advance.
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Re: Fly cutter for skimming cylinder heads.

Postby bill jones » Sat Sep 18, 2010 7:25 pm

-if you are going to buy one here's some of my thoughts about the subject.

1-a Bridgeport typically has an R8 collet quill.

-I feel the R-8 shank diameter is pretty puny for swinging a large diameter flycutter.

-On normally head milling machines the typical cutter diameters are usually way larger than you'd ever use on a Bridgeport and you'll probably have to seriously compromise the diameter to get rid of chatter.

-and normal head milling machines have the cutter tilted down on the forward edge slightly so the rear of the cutter doesn't drag a pattern part way across the head as it starts to come across the back side near the end of the cutting pass.

-some people try to run a small diameter flycutter and make multiple passes and I personally feel this is nearly a futile effort.

2-I have a mill but it happened to have a #30 quill which in my estimation is substantially stronger--so I built my own cutter using a SBC cast iron flywheel.

-this gets me about a 11" cutter path----and I try to tilt the head of my mill very precisely to drop the leading edge down .001" and the trailing edge up .001" as a minimum to maybe as much a .0030" total tilt.

-even with this minimum amount of tilt this causes the cutter to machine several thousands of concavity which is actually measurable across from the sides of the head---about .002".

3-feed and speed and depth of cut---I use 6 adjustable cutter teeth---carbide tipped boring bar bits---into the underside of my flywheel based cutter.

-I wanted the cast iron rather than steel--to eliminate most of the chatter or vibration.

-I hand sharpen my carbide cutters using a diamond wheel on a 3/4hp grinder motor.

-the cutters do not all cut exactly the same in regards to the leading edges of the cutters---but they can all be adjusted to exactly the depth.

4-Cast iron heads, aluminum heads, where you are only cutting cast iron or aluminum--meaning not machining thru valve seats or other hardened rings like is common on diesel heads---means you have basically have to get the rotation speed, the feed rate, and the cutting depth figured out for each of the two metals.

-but when you have the cutters hitting hard seat or the rings you have to cut across on the diesel heads---now you have totally different issues to deal with---mainly chatter and smear.
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-I built my own because I didn't see anything on the market at the time (20 years ago or so).

-here is some story and pictures of my setup---and I can machine decent surfaces and do it all in a timely manner.

http://ryanbrownracing.com/Bill_Jones_Page_1.html
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-All I'm trying to get across here is I feel that anything you can buy for a Bridgeport is going to be a compromise---and I really don't know if it's possible to get the rigidity speed using an R8 quill.

-There should be about a hundred guys on here who are using Bridgeports---so you should be getting their advise and stories here shortly.
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Re: Fly cutter for skimming cylinder heads.

Postby ShaunK » Sat Sep 18, 2010 11:43 pm

Well thank you Bill I appreciate the time you took to reply. At the last engine machine shop I worked at he used a flycutter on the heads and had great results however we ended up not seeing on to eye about a few things and I can't remember if he bought the cutter or he made it. Your set up looks well thought and very functional!
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Re: Fly cutter for skimming cylinder heads.

Postby cpmotors » Mon Sep 20, 2010 9:32 pm

I think High Quality tools has one that AFD and SRH are using that works really well-
I sell a fixture for holding those heads on your Bridgeport that works pretty good-
Pete Graves
CPMotorworks,Inc.
Custom Engine Machining
Cylinder Head Fixture for Vertical / Surfacing Mills
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Re: Fly cutter for skimming cylinder heads.

Postby jimjamm65 » Tue Sep 21, 2010 6:58 pm

shaunk, i bought an 8" fly cutter from PMS (precision measurement supply) in san antonio, texas. it has an r-8 shank and works real well on a bridgeport. i use a head holding fixture from a storm-vulcan block master i bought at an auction. have cut many heads, no problems.
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Re: Fly cutter for skimming cylinder heads.

Postby JBV-HEADS » Sun Sep 26, 2010 7:23 pm

I’m getting rid of some surfacing equipment that was for my CNC or a mill. This thread made me think that someone should get some use from them. I’d prefer an engine builder but some CNC guy may just get them. I’m not sure on the rules to this site but I’ll list the eBay links or you can search cpengineperformance there to find them if the site removes the links. They are meant for a small to large engine building shop. The one is serious CNC only or NMTB40 or bigger. I hope someone in the business gets them though. Good luck.

http://cgi.ebay.com/ebaymotors/ws/eBayI ... ESELX%3AIT

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... :MESELX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... :MESELX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... :MESELX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... :MESELX:IT

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Re: Homemade Fly cutter for skimming cylinder heads.

Postby madmikeracing » Sun Feb 13, 2011 5:02 pm

I been watching this site for a Long time. I use a Homemade Cyclinder Head Facing Tool. It is adjustable up to 8 inch diameter. i have run it in my bridgeport over 2400 RPM with NO shaking or vibration from the tool. If you wanna see a picture email me youre email. I can send you a pic or two? I may even make a batch up id enough intrest. They are the BEST Ive seen in near 40 years aerospace amchining . Thanx Mike
avmmachine@rogers.com
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Re: Fly cutter for skimming cylinder heads.

Postby crazycuda » Tue Feb 22, 2011 12:48 am

Ive used the BHJ cutter on my mill with no issues on back cut. On any head with a surface area wider the a BBC id be nervous with the cutter tips hanging out so far from the body though.
John Mann
Action Automotive Inc

Sorry if I ask alot of questions, but you never stop learning if you ask questions
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Re: Fly cutter for skimming cylinder heads.

Postby HDBD » Tue Feb 22, 2011 3:08 pm

Consider a SuperFly made in Kent, WA. Sold by swift tool in R-8. Uses two standard lathe brazed carbide 1/2" bits. Best finish I have found and well balanced. I set the leading bit .010 higher than the other so the other takes a light finish cut only. I use A6 lubricant on aluminum.
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Re: Fly cutter for skimming cylinder heads.

Postby pdq67 » Fri Mar 25, 2011 5:16 pm

Probably way over-kill here but APGreen Refractories used to diamond Blanchard their old ArcHard-D zero porosity, way high-fired, like 99 percent tabular alumina product!

Once we had a plastic gunning machine's feed wheel flame sprayed with TiC to build it up and when it wore down, we had the machine shop reface it using a wore-out Blanchard diamond wheel and the machine shop foreman came back and said thanks because our feedwheel's flame sprayed surfaces were hard enough that it kicked the diamond matrix such that they came to the surface and was good to use again.

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Re: Fly cutter for skimming cylinder heads.

Postby mvpmachine » Thu Oct 13, 2011 8:10 pm

We make a carbide inserted adjustable fly cutter that works great for cylinder heads. Running a large fly cutter on an r8 Bridgeport if the cutter is properly made and if your spindle is in decent shape (no slop) is not a huge problem but requires some patience and practice (on a scrap head). Ideally a 30 40 or 50 taper machine would work better because rigidity is almost everything. The main problem I see with most available or "homemade" fly cutters is the use of 1/2" grind your own tool bits, whether they are carbide or high speed steel, the angles are all critical, and to have an of the shelf carbide tool bit cut right in a fly tool configuration without modifying it is asking a lot for a tool designed to run on a lathe. In addition the lack or rigidity in a 1/2" tool bit bar is a big weakness. A single point tool will almost always provide the best finish and flatness as long as you are not taking huge depth cuts and your tool is rigid. Regarding chatter aside from spindle slop and machine slop it is a harmonic phenomenon as well as a material condition phenomenon, the old theory speed up feed and slow down rpms may work on a lathe to eliminate most chatter but surface milling with a fly cutter you are always making an interrupted cut because the tool bit or bit have to enter and exit each side of the work piece and that creates bounce. The bounce becomes a harmonic within the fly cutter, machine and workpiece. In most cases adjustments in rpms and feed up or down can eliminate the harmonic or chatter. In some cases painfully slow feed and speed rates are required to accommodate machine issues or workpiece rigidity issues. We just started selling our fly cutter on ebay after having made them for friends and local companies here in the Detroit area for the last 7 years. Here is a link: http://www.ebay.com/itm/Large-Diameter- ... 4aafb0c029
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