Flycutter Balance Problem / Question

[Subwayrocket]

I have a Suburban Fly cutter and their 5" bar . I started getting familiar with it by facing off all my aluminum chill blocks. Roughly 4"x5" one inch thick 6061 blocks . The fly cutter works great but I have to run it in low range in my mill, which is 370 RPM and slow table feed . I can run it in High 1 which is 650 RPM and it makes a nice finish, but it has some wobble vibration that i'm not comfortable ...think washing machine on spin cycle ...but not quite that bad. My mill is a PM940 , not a mini but not real heavy either .
I was thinking about tapping the back end of the cutter bar for a bolt that I could put weights on to counter balance the thing , maybe washers , drilled brass or lead weights ??? I donno , just kind of mulling around the idea .

Anyone have any thoughts on this ? Here's is a short vid of some old vice jaws I welded in some deep cuts, gouges and dings . Roughed off the welds with and end mill flush to the original surface, then took a 0.005" fly cutter pass and another pass at 0.004" , both at 370 RPM and slow table feed.

Any input is appreciated , Thanks !
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[TomS]

I read your other post where Dan S commented that the cutter bar may be hardened. Test it with a file. If it cuts with a file then drilling and tapping a hole shouldn't be a problem. Reducing vibration cannot be a bad thing.

Tom S.

 

[chips&more]

I would report the problem to Suburban. If they made a fly cutter that looks pretty but does not function correctly. Then their design team needs to go back to the drawing board…Dave.

 

[Billh50]

As far as I know it is almost impossible for a fly cutter to be balance unless you have the same amount of stock sticking out both sides. And in some cases that is just about impossible. The only fly cutters I have seen are only adjustable in the up and down with the tool which is on one side. The ones where the tool is already set at a downward angle are already unbalance because stock is taken off the face at angle to one side.

 

[BRIAN]

When I have a balance problem with a fly cutter or my boring head I use a worm drive hose clip as a balance It normally solves the problem .
Brian.

 

[Subwayrocket]

I would report the problem to Suburban. If they made a fly cutter that looks pretty but does not function correctly. Then their design team needs to go back to the drawing board…Dave.

They do clearly state on their website that it's an unbalanced tool, never operate over 1300 RPM , and likely much less depending on your machine. So I was aware of it and that's why I've been using it at 370 Rpm . At 650 there is a little shake to the whole machine and I know it's because of the imbalance i've been thinking about trying to resolve.
If I had a 2000 lb machine it would probably no happen, but my machine, base and leveler base is only about 1300-1400 lb . The tool still cuts a mirror finish at 650 Rpm, I just don't like the shake ...

When I have a balance problem with a fly cutter or my boring head I use a worm drive hose clip as a balance It normally solves the problem .
Brian.

Do you mean something like the picture below ? I was thinking about trying some type of C-clamp with a little weight attached on the side opposite the cutter. When you use the worm drive hose clamp, do you clamp any extra weight opposite the cutter ? The clamp alone wouldn't balance this.
The hose clamp is a good idea I hadn't thought of, Thanks !
I have the 5" bar and I use it with the cutter end pushed far as it will go into the bar holder. With it like this, I basically have about a 3/4" cube of steel sticking out on the cutter side and only about 1/4" on the opposite side....hence the imbalance.
I am only using this fly cutter for finish cuts of around 0.005" ...I roughed down close with end mills , so the fly cutter is not really pounding off a lot of material, but the imbalance is there before I contact the work.

Thanks guys , I appreciate the input !

 

[Billh50]

Boring heads are the same way. the farther you move the head out to bore the more unbalance they become. At slow speeds it is not a problem. But becomes more noticeable as speed is increase.

 

[Subwayrocket]

I never noticed that with my boring head , probably because i've never run it in anything other than low range.

 

[Billh50]

Fly cutters like the one Subwayrocket has do not have a noticeable unbalance when the tool is in as far as it goes. The further out the tool sticks out the more weight it would need in the back of the tool to keep the balance at high speeds.

 

[Rick Berk]

I would call Don and discuss with him, he will probable tell you your bearings are shot in the quill head.