Boring bar to fly cutter

I think that the OP is just trying to use what he or she has on hand to make a usable tool for what ever part they are making. As this site implies most are just Hobby machinists we are not all flush with money that we can just go out and buy that perfect tool to get the job done. Many are probably on a fixed income and still wanting to have a hobby to keep them busy just the material now days takes alot out of the budget. It is nice that some people on this site try to keep that in context when they offer help. I only have a small 9 x 20 lathe and mini mill and have made many parts and tooling with both but it does take a bit longer and slower. I'm sure it would be great to just go buy any tooling needed but not always possible. When you see some of the shops some have they are much larger and better equipped than any home hobby shop. Thanks to all who are willing to still help the Hobby Machinist.
 
Safety should ALWAYS be the number one concern regardless of the machines / tools we own . We try to stress this on this site , at home and in the workplace . Using a boring head with a tapered shank to fly cut is pushing the limit . If the interrupted cut pulled that taper shank out of the machine or un-screwed while running all holy heii would break loose . If the shank had a drawbar holding it in , it may be a different and safer operation , but still , not the correct tool for the job . We all do things to get by with what we have . Sometimes it works out and other times it doesn't , so we have to consider the " what ifs " if they do in fact happen . :)
 
extropic said:
Less insert edge in the cut = lower cutting forces (all other factors being equal).

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Click to expand...

^^^^ I found this sentence to be very illuminating!

I knew this with regard to depths of cut, but I had never thought about it for cutting tool rake. Thanks for the insight, @extropic.

Regarding the topic of the thread, I wonder if the OP’s idea could also be used for trepanning on a milling machine. I have never even thought about trepanning on a milling machine.

For the OP’s project, my initial reaction was that the setup would not be rigid enough, but taking lighter cuts (as you do with a fly cutter, anyway) + extra spring passes would compensate for this.

Also, kudos to the OP for thinking outside the box.
 
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Stop...

The mill does not have the ability to be effective at that distance unless making plastic plates.

Other than power and rigidity the table is just too small.

To use as fly cutter configure as normal boring head and adjust for hole at large diameter.

It will act as a fly cutter more within limits of machine.

This is using tooling creatively.

Fly cutters are cheap, also easy to make.

Better to make one from cheap materials than to ruin expensive materials to improper use of something else.

Fly cutter would be cheaper than the ruined boring bar.

Sent from my SM-G781V using Tapatalk
 
tq60 said:
Stop...

The mill does not have the ability to be effective at that distance unless making plastic plates.

Other than power and rigidity the table is just too small.

To use as fly cutter configure as normal boring head and adjust for hole at large diameter.

It will act as a fly cutter more within limits of machine.

This is using tooling creatively.

Fly cutters are cheap, also easy to make.

Better to make one from cheap materials than to ruin expensive materials to improper use of something else.

Fly cutter would be cheaper than the ruined boring bar.

Sent from my SM-G781V using Tapatalk
Click to expand...

I always ask myself “What is the weakest link here?”. In other words, if things go wrong, what will fail? If the weak link is the gears in a gearhead lathe, I will not use that setup. If the weak link is belt slippage, I will start out with a really small depth of cut. If even light cuts cause the belt to slip, I will almost certainly start looking for a different plan.

In the case of the OP, I think the weak link is the deflection of the boring bar. I have tried cutting operations on steel in which there is way too much tool stickout whereupon I failed to be able to execute the cut. The cutting tool would either break (e.g. a parting tool) or the boring bar would deflect & skate over the workpiece.

I have boring heads, but I have not yet had occasion “to use the side hole”. If ever I do so, I would take lighter cuts, extra spring passes, the best quality of inserts on hand, & a solid carbide boring bar if I had one in that sized shank.
 
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First of all, I really apreciate all your help and the time you are spending with all your explanations. And as allways, I have learned a lot.

chip maker has described me perfectly, but mmcmdl is right too. And reading him I got the same conclusion as Liljoebrshooter. To use this boring bar the rotation of the spindle could loose the drawbar, so I won´t be able to take advantege of this boring bar. I´ll buy something like this.​

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https://www.mesatool.com/product-page/2-boring-head-attachment-w-ccmt​

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it seems solid, and the correct tool for that job.​


Thank you again!
 
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