Jammed insert.

I bought this Chinese made indexable holder (16mm shank) and some inserts a little while ago. It’s a design I have never used before but I have been very pleased with its performance. However, the insert has become blunt and needs turning and this where I am having a problem. I cannot shift it. The clamp part I have no problem with, it’s the location pin that goes through the hole in the insert that will not move. I do remember that when I fitted the insert I had to loosen the pin to get the insert to go over it and then tightened it ready for use.

Looking at the top of the tool, the pin has a hex socket for the allen key. Looking at the bottom of the tool - and the pin hole - there is a hex socket there as well. I don’t remember whether the pin assembly is in two parts or just one bit. So the question is - to remove the insert which bit of the pin should I loosen first? Top or bottom? Also are both ends RH threads? Thanks in advance.

Rik

As far as I understand it the hex socket in the underside of the pin is basically put there so it can be installed and removed. The pin will be a snug fit in the insert but the inserts usually slip off, maybe with a little tap.

If you can rotate the pin without damaging its hex recess then you could unscrew in which case it will act as a tip ejector.

Ian P

Hello Rik,

I think  this design moves the pin to draw the insert back into the recess, using the bottom half of the screw and completes the clamping with the overhead finger. After a long period in one position it may be reluctant to move back and a light tap with a soft drift may well release it

Regards Brian

Edited By Brian Wood on 26/07/2016 11:50:54

Hi Rik

I have some similar holders although not made in China, the larger screw that tightens the lever that clamps down on the insert may have a hex drive top and bottom allowing you to use two hex keys at a time on the same screw you may find your screw has the same configuration. This allows double the force to be applied without risking cracking the hex socket.

The screw is actually a differential screw with two different threads, if you remove it completely you may find it does not engage the clamp correctly the clamp will be too high or low. try it a couple of times until you get the correct sequence to set the clamp in the right position.

The single central pin screw also should have a cam action that when you tighten it draws the insert laterally towards the holder. Try using two keys on it too, It should move.

I rather like this setup a very secure system that securely clamps the insert.

Regards
John

Update: Thanks all for the advice so far but still no go. I've tried my chefs blow torch on it but it makes no difference. Just to clarify - the problem is with the insert location pin/screw - it won't budge. The larger overhead clamp and its screw work fine. - Rik

Surely top screw is only to clamp the insert down, so can be removed completely. Looking at toolholder from underneath, by rotating socket screw anti-clock, this should allow eccentric pin on other end of this to rotate anti-clock and unclamp the insert which it's pulling back towards the clamping hole?

Regards Ian.

Thats a holder for negative inserts, and the top screw as stated earlier only serves to hold the insert onto the pin. Its the pin that when tightened draws the insert firmly into the pocket. Most [all? ] have it so the pin is attached at right angles to a bearing part that will "tilt " when the screw is tightened. If the insert is still held firm try have you tried turning the screw in the opposite direction? I have a few of that type [Arno and Sandvik ] and they all work in the same way.

Just break the carbide insert into pieces with a hammer and a hard punch. Once the tension from the insert is released the screw will probably unscrew easily, but if necessary the screw will be left proud so you'll be able to grip it with pliers or mole grips.
OK you sacrifice the insert but it pretty well guarantees you'll save the screw.

Hope that helps!

Can I say - buy a better tool holder?

**LINK**

"Can I say - buy a better tool holder?

Try some hot/cold cycles with the freezer - and some penetrating oil.

Wait until you are starting the final half-a-thou finishing cut on a vital and complex part, using this tool, and you will find that the carbide insert shatters when your neighbour's cat sneezes in the garden.

It always works for me ...

Tim

As SteveM suggests, I would be tempted to break the insert to remove it to see if that would free up the pin. On my combination toolholders the pin is on an eccentric, no threads. In a pinch I could use a small punch to drive it upward and release the insert.

If the pin has a standard thread you may need to turn it clockwise to release i.e. to get it to move upwards?

It's ongoing Neil. The sod remains resolutely jammed. It should not need penetrating oil as the insert was only installed a fortnight ago in an oily environment. I have given it several doses of your freezer treatment with no result. For the ten quid which the holder cost me I am nearly ready to consign it to the pit of oriental naffage which it deserves but unless some kind soul comes up with a solution in the next day or so I will go with Steves advice and attempt to destroy the insert with a punch/chisel and a big hammer - although I strongly suspect that the insert may fight back. - Rik

Can you use a Dremel with a diamond disc to cut the insert between the pin and the shoulder? If you can cut or break ithe insert I suspect the pin will move freely.

I go with those that say that bottom screw is a screw with an 'off-centred peg' on the end. It will turn one way or the other to 'uncam' the insert from its secure tight-fitting position. Technically, I would guess, it does not need to actually be tight, once the securing clamp is fully tightened and, although it would normally remain tight, if it came loose, it could not unscrew unless the insert moved.

I would guess that it will release the insert by turning it inwards - clockwise - as it would normally be initially positioned almost fully screwed home, thus tightening the insert by turning outwards, in an anticlockwise direction. Well, I have a 50%chance of being correct!

Why wait 3 1/2 days to do it.

Just get a hammer and whack the bugger

Before you whack it, put a rag around it, that will stop the bits flying around the workshop.

Ian S C

If the clamp can be removed then all that is left is the insert sitting on a pin.

I would just mount the tool in the bench vice and using a (soft) punch try tapping it under the edge of the insert from each side. it probably overhangs slightly. this should be enough to raise it slightly off the pin. allowing you to gently lever it off (There is probably a carbide seat under the insert, you don't want to damage that, replacements are available)

The pin does not have eccentric cam action. it works by a taper and the positioning of the tapped hole in the tool holder. As you screw it in it moves laterally slightly tightening the insert against the tool body.

Before any of the above I would try (two) hex wrenches top[ and bottom and try to unscrew the pin. Assuming it has two as my similar tools have. It should unscrew.

Regards
John