replacing inserts

[savarin]

I have a set of ebay carbide tools.
Anyone know how to replace the inserts?
There is a hex grub screw underneath the bit but it appears to be impossible to turn.There is only what looks like the bottom of the grub screw showing in the centre hole of the insert a little way down.
I have twisted a good quality allen key attempting to unscrew the grub screw so I'm stumped at the moment.
Thanks
Charles

 

[8ntsane]

You might want to take a close look at the head of the screw with a magnifier. I have some that have (torx screws) but usually they come with the proper tool as well. The torx type are not the same, and allen keys may damage them .

 

[Tony Wells]

A few, but not all, will have hex sockets in both ends so you can use two wrenches at the same time. Not seen a double Torx, however. Is it a screw, or a cam? Can you put up a photo?

In desperation, and I hate to admit it, but I have cracked some inserts out because I had to change them. It's easy to damage a pocket doing so, so it's a last resort.

 

[savarin]

Its definitely a hex socket.
I also tried heating as I applied pressure but no luck.
Heres two of them showing from above and below with the twisted hex key.
I havnt been able to move a single one of them.

 

[7HC]

Try soaking for several day in Kroil or the 50/50 ATF/Acetone (or rubbing alchol, or wintergreen) mix.

M

 

[Tony Wells]

That's a cam, not a screw. It's hard to tell which way whoever put the inserts in tightened it. It will tighten either direction, so you may have actually been trying to tighten it instead of loosening it. Some holders have an arrow to give the proper direction, most do not. Look very closely at the insert hole and the pin and you may be able to tell which way it should turn. If not, it won't hurt anything to try the opposite direction from what you have been working. Sometimes, cam pins are a hassle, just because of this.

 

[OldMachinist]

From the looks of the cam pin you need to turn the wrench counter clockwise to loosen it.

 

[savarin]

Try soaking for several day in Kroil or the 50/50 ATF/Acetone (or rubbing alchol, or wintergreen) mix.

M

Whats ATF?
I have one in penetrating oil as we speak.
I have tried both left and right to loosen them. I didnt "know" they were a cam lock but did wonder as the top of the screw looked off set so thats why I tried both ways to loosen just in case.
There is definitely a thread on the grub screw so maybe screwing in will loosen. I will try an impact driver if nothing else works and if I destroy everything I guess I will have to chalk it up to experience.
I will keep you posted as to what eventually works if at all.

 

[savarin]

Well, that was quick.
They are cam locks and tightening the screw (very difficult) after the penetrating oil worked.
Thanks everyone.

 

[Tony Wells]

For future reference, they really don't need to be that tight. Pretty snug, but obviously not so tight that you have to soak, heat, beat, or twist wrenches to release the cam. By chance, is there an arrow to indicate the proper direction to tighten?

Oh, ATF is Automatic Transmission Fluid. A 1:1 mix with Acetone will work well as a penetrating oil. Some say it is about the same is Kroil. I haven't used Kroil, but I have used the ATF/Acetone mix.