# Homemade Indexable End Mill?



## Robo_Pi (Feb 9, 2019)

Anyone make any homemade Indexable End Mill cutters?

I'm looking at this one on Amazon for $40



This one seems pretty nice at a fair price.   It's 1-1/2" with a 3/4" straight shank.    I need either a straight shank like this or an MT3 taper. 

I would also like to have a set of these in maybe 2", 3", 4" and 5".   But I don't want to pay a ton of money for these.  So I'm wondering if anyone has ever made their own homemade indexable end mills?  I've seen a lot of videos on making homemade flycutters, but never saw one with multiple insert cutters like this. 

I'm thinking the body shouldn't be too difficult to make.  And then just buy the carbide inserts.   In fact, if I made my own set I'd make them so they all use the same inserts so I can swap inserts between them if need be.    A set of indexable end mills like I would like to have could get quite expensive.    So the idea of making a homemade set is quite inviting.   Especially since I would be just fine with a 3/4" straight shank with a flat milled on it.  That part would be super easy.  The only difficult part would be to cut the flats where the carbide inserts are installed.   I would imagine those inserts would all need to be lined up pretty close tolerance to each other. 

Other than this it looks like it would be a fairly easy project?

Can you share your experience with making these?  Or point to YouTube videos where others have made them?

Or maybe another thread where this question was already asked and answered?  I tried searching for such a thread but came up empty.

Thanks.


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## Dabbler (Feb 9, 2019)

If your interest is in creating tools, them make it yourself - but I prefer to make 'things' with 'tools' so I buy all of my tooling...

I have 2 indexable offshore lmilling cutters, and they work well for me, and I think I paid $40 CAN for both of them with inserts.


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## Norseman C.B. (Feb 9, 2019)

If you have, or can make the tooling needed to do it, and the time needed have at it !!
the only thing that can stop you from doin it is you.
Reverse engineering is fun fer me, and gets tooling made that I need to make more tools to make stuff
I want so I can make other tools and stuff that I need and......................( Vicious cycle man  !! ).........................


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## Ecosta777 (Feb 9, 2019)

That's a face mill, I wouldn't try to do any endmilling with that. Why would you need so many anyways? For a face mill you might as well just get like a 3" and maybe a 5" if you wanted to do larger faces in one pass. It can be made, anything can be made in a machine shop! Its just a matter of if you care to take the time to make it yourself. Personally I'd give it a go, nothing more satisfying than making and using your own tools!


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## Bob Korves (Feb 9, 2019)

Making the pockets to hold the inserts can get fussy.  If too big or inaccurate, the inserts move or are held in the wrong places, and then you have a poor finish and only 1 or 2 inserts doing most of the work.  Do your best to get all the cutters cutting in the same path, and mounted so they can stay that way.


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## Robo_Pi (Feb 9, 2019)

Ecosta777 said:


> That's a face mill, I wouldn't try to do any endmilling with that.



Accusize is selling them on Amazon as "_Indexable End Mills_".    I have no clue.   But you're right, I'm only thinking about using them for face milling.  You're also right that larger sizes can probably be used for smaller jobs in most cases unless you're trying to face the bottom of a channel where a larger diameter cutter won't fit.   That was my thinking with having a variety of sizes to choose from.



Ecosta777 said:


> Personally I'd give it a go, nothing more satisfying than making and using your own tools!



That's my thinking too.  That's why I posted this question in the Tool Junkies thread.  You have to be a real tool junkie to wanna do this.  



Bob Korves said:


> Making the pockets to hold the inserts can get fussy.  If too big or inaccurate, the inserts move or are held in the wrong places, and then you have a poor finish and only 1 or 2 inserts doing most of the work.  Do your best to get all the cutters cutting in the same path, and mounted so they can stay that way.



Yeah I imagine they need to be pretty precise.   That's why I would like to see a video of someone making one.  Just to get an idea of how they tackled the precision deal between the cutter inserts.   No point in reinventing the manufacturing process if someone else already has perfected a technique to make the job easy.

I see a lot of homemade fly cutter videos.  But those are so easy to make there aren't many secrets there.   As long as it holds the single cutter solid enough it will cut anything that gets in its way.

I'm also thinking, but don't really know, that one of these multi-cutter facing mills would produce a nicer surface than a single bit fly cutter.  That's just a guess on my part.   I suppose it could be better or worse depending on how precise the cutters are positioned as you point out.

I already have an indexing head:








So I'm that far along. 

It would seem to me that once I set up to mill the cutter slots, just indexing through that process should produce some fairly precise results.   I wouldn't even think about making one of these cutters if I didn't already own an indexing head.   Although there are no doubt other ways to do it as well.   But with the indexing head it really should be a piece of cake, don't you think?


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## Bob Korves (Feb 9, 2019)

You will need some kind of pockets or other means to hold the inserts in the desired places.  Watch this video:




and note the precision Randy uses to make the pockets for the inserts.  This is only a single insert cutter.  With multiple cutters, the quest for accuracy and repeatablility gets even more important.


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## Robo_Pi (Feb 9, 2019)

Thanks for posting that Bob.  I never thought to search for a homemade dovetail cutter.   I'll be needing some of those too, so I'll definitely make my own dovetail cutters.  They are pretty simple.



Bob Korves said:


> note the precision Randy uses to make the pockets for the inserts.



Actually the only place where he used great precision with a dial indicator was when he was finding the center line.   When he actually set up to drill the tap hole for the cutter screw he basically just eye-balled it using a mirror.    I think I would use the indicator for that as well.



Bob Korves said:


> This is only a single insert cutter. With multiple cutters, the quest for accuracy and repeatablility gets even more important.



But that shouldn't be a problem with the dividing head.   All you do is take great care to set up the first cutter pocket, and then just index through using the divining head.   All the remaining cutters should be identical.   You won't need to remeasure each one individually.    Same thing goes for setting up the tapped hole for the mounting screw.   Once you have the first one set up, just index through again and they should all be identical.  

The key is to not move anything between indexing.   As long as you have a good solid indexer it shouldn't be any more difficult to make multiple cutter pockets all identical.  Whatever you did on the first pocket will just be repeated on every pocket after that. 

If you tried to set up each cutter individually it's highly unlikely they would all be the same.   That's the whole point of a dividing head.   Just set up once and then repeat for as many divisions as you want. 

But yeah, thanks for this dovetail video.   That's pretty close to the same idea save for some geometry.   Plus I'll be needing some dovetail cutters anyway, so maybe I'll make some of those first to get my feet wet.

I'll most likely buy that factory made cutter I posted in the OP first, and then use that for ideas on what geometry to mill for any multi-bit cutters I might make.


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## Robo_Pi (Feb 10, 2019)

*How to cut a Dovetail*

This is a slight aside from the original topic of the thread,  but I just found the following video of a fellow actually using the dovetail cutter that was made in the video Bob just posted.  I thought I'd post this video here for anyone who might be interested.


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