Asian Face Mill issue

Tio Loco

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I know, you get what you pay for, but I purchased one of the 2" 4-flute Asian face mills from ebay. It can produce a very nice finish, but seems to have one insert that sets lower than it's siblings.

I've tried reseating the inserts, rotating them to another face, and even buying a new set of higher quality inserts, but I still have that one dragging insert.

Is there anything that can be done? The position of the inserts seems pretty fixed as far as their position. About the only thing I haven't tried is running it with just three inserts.
 

Tio Loco

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Unfortunately, the pocket depth doesn't set the insert position, the center screw for the inserts does. The pocket only serves to keep the insert aligned.
 

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benmychree

John York
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How much does the insert sit high? If it is minimal, deepening may be possible, as the screw in this type of cutter does indeed force the insert into the pocket, by being located non concentric with the insert hole.
 

Janderso

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Hmmm,
I have one of those. Works great though.
I'll take a closer look.
 

Flyinfool

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You need to some very careful measuring to figure out what the actual issue is. it could be that the pocket is not quite right and the screw is not actually centering exactly on the insert, or it could be that the screw hole is in slightly the wrong position. OR combination there of.
If it is the pocket that is off that should be easier to fix.If the pocket is to small then just machine it till it is correct. If the pocket is to big, Weld or braze in some material and machine it correct.
Moving a threaded hole a few thou is a PITA. But it can be done. Either just weld it closed and re-drill and tap in the correct spot, it is not easy to fill a high aspect hole with weld. OR drill it out and press and weld in a pin and then drill and tap correctly. Or possibly if you can get it setup ridgid enough, bore, drill and tap in the correct spot for a thread insert.

This could be one of those cases where it is cheaper to go out and get a new tool than it is to repair this one, but doing the repair might just be fun in its self and a good exercise in precision, and net you some other new tools along the way.
 

benmychree

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So far as it goes, I have never seen an insert facemill that does not have a high insert, even the adjustable ones are not perfect, and perhaps the inserts are not that close to being the same size, unless they are the precision ground type. I think the first thing to do is determine whether the pockets are all in the same plane, then whether the inserts vary in height.
 

westerner

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Thanks for this post, Crazy Uncle. I feel your pain.
I have a three flute 2" tool that has this exact issue. For what I paid, I cannot expect more. I fiddled with inserts, rotated, changed out, blah, blah, blah.
I use it primarily for hogging off a bunch, and so finish is not important. If I am looking for a better finish,
I have done as others have suggested, and turned the thing into a funny looking fly cutter.
I have not taken the time to measure the problem, and am content with the results obtained.

As I have stated previously, NASA has not offered a contract here, and Boeing has not sent any RFQs. (Request For Quote):cautious:
 

ddickey

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I have one of those too. It is only used for roughing as only two inserts sit on the same plane.
 

T Bredehoft

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Perhaps you could shim the low inserts up to match the high one.
 

pontiac428

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If you know someone who has a T&C grinder, or a surface grinder, or even a bench grinder with some sort of indexing work head, or possibly a lathe tool post grinder, you can regrind the bottom facets of the inserts (while mounted in the holder) perfectly even with each other, and be off to the races.
 

Tio Loco

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Wow, thanks for all of the feedback and suggestions. Maybe I'm just quibbling, but it does produce a nice finish, but I suspect that would deteriorate if I used a faster feed rate.

I'm gonna take a closer look today with an idea of fixing the pocket. Anything beyond that is probably not worth the time or brain damage. If that won't fix it, a three legged dog... er.. face mill may be the ticket to happiness. I'll let you know...
 

Illinoyance

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Technical Ted

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I don't know what mill you have. I looks from the picture that it's an R8 holder.

So, first, determine in your spindle is running true. Check the taper in your spindle with a test indicator. If it is off, the face mill might not be the problem.

If the spindle looks good, check new inserts in the cutter (the bottoms, radius tips and sides) with your test indicator and get some readings. Check them as you revolve the spindle by hand very slowly over the cutting edges. Mark each flute so you don't get your recording mixed up. Depending on what you find, maybe you can tweak the pocket with a small, fine, file. Be careful, because you could do more harm than good, but if it's only off a thousandth's or so, a slight touch, or burr removal, might be all it takes.

So, first, determine where the problem is. Then, address the problem

Good luck,
Ted
 
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