Indexable tooling

This topic has 18 replies, 9 voices, and was last updated 13 August 2011 at 08:37 by Gary Brooke.

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9 August 2011 at 09:22 #5610
Gary Brooke
Participant
@garybrooke63895
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9 August 2011 at 09:22 #73071
Gary Brooke
Participant
@garybrooke63895
Hi guys
I need to pick your brains again. When facing bar, I am getting the tool digging in. On closer inspection ,discovered that the tip had worked lose. After tightening was all right for a while then came lose again.
Has anyone had this problem and how to solve it ideas please or should I be using solid tools.
Many thanks
Regards
Gary
9 August 2011 at 09:53 #73072
Martin W
Participant
@martinw
Gary

While I have never had this problem I wonder if there is something trapped under the indexable tip. It mat be worth taking the tip off ensuring that there are no debris between it and the tool body. When I change tips I always clean the mounting surface of the tool and the tip thoroughly.

I find that I have the reverse problem with tips in that the screw is always very tight and almost seems to tighten during use, this is only a qualitative feeling with no firm proof.

Another possibility is that the tool body, where the tip mounts, is not perfectly flat or the recess is not a good match for the tip and is allowing the tip move and work loose.

Cheers

Martin
9 August 2011 at 12:30 #73073
JasonB
Moderator
@jasonb
The only time I’ve had a tip move was in a holder that was not a good fit on the tip.

Are you using teh original screw, if you have changed it then it may not be correct, they may all look the same but there are slight differences between makers.

Also worth getting a decent “T” handle torque wrench rather than the little allen key type usually supplied, I find the Eklind brand good quality.

J
9 August 2011 at 14:10 #73077
mick
Participant
@mick65121
Is this a cam lock or counter sunk screw type? If cam lock are you tightining the cam in the correction direction
9 August 2011 at 14:58 #73078
Ian S C
Participant
@iansc
The tips that I use are 16 mm triangle with no hole, they are clanped into the tool holder with a bridge piece, and seem very secure, I make my own tool holders, as considered the ones available were well outside my budget. I used a bit of car rear axle to make the holder. The bolt that holds the bridge is a 10-32/ 3/16″ unf hex head high tensile one. Ian S C
9 August 2011 at 15:20 #73080
Pat Bravery
Participant
@patbravery
If the screw has been over tightened at some time then it will probably be stretched and will keep coming loose. Best advice is fit a new screw. Best regards Pat
9 August 2011 at 15:43 #73083
chris stephens
Participant
@chrisstephens63393
Hi Gary,

A few things come to mind regarding your problem. First the obvious one, is your bridge piece stiff enough and is bending? Second, as you say you are facing, could it be that you are going past centre and therefore putting extra strain on the bridge by suddenly trying to lift the insert.

chriStephens
9 August 2011 at 16:18 #73086
Ian S C
Participant
@iansc
Chris, I don’t think Gary’s tips are held by a bridge, just a screw through the middle. The bridge clamp can be used on any type of tip, hole or no hole, I’v uswed it on tips designed for brazing. Ian S C

PS., while I’m writing this, the BBC news is on TV, WHAT THE H**L’S going on, have the kids over there gone nuts?
9 August 2011 at 17:24 #73088
Gone Away
Participant
@goneaway
I had exactly this problem on a set of cheap Asian-made holders.

There was clearance between the insert and the shoulder it should have been sitting against. As far as I could see, no matter how tight the screw was, the cutting forces could rotate the insert about the screw.

I placed a shim between the insert and the shoulder to take up the gap and the problem went away.

Probably a better solution would have been to by decent holders (which I have since done).
9 August 2011 at 18:07 #73089
Martin W
Participant
@martinw
Ian

It’s quite easy to explain what is going on over here. Basically some of the ‘underprivileged and under achieving’ from the ‘deprived areas’ who are probably bleeding the benefits system have managed to climb out of the cesspits they call home and infect the streets of some of our cities.

But not to worry as the ‘do gooders’ will no doubt say that it only a sign of their frustration and lack of opportunity and that the police are at fault in being heavy handed and provoked the situation by asking them to stop looting shops and setting fires.

But that’s modern Britain for you, no discipline and no respect and parents that are more interested in possessions than their kids.

Yeah if you want a good mugging then come to Blighty and get it done properly, something we can be truly proud of.

Cheers

PS Sorry if this is off topic but the question was asked.

Martin
9 August 2011 at 18:16 #73090
Gary Brooke
Participant
@garybrooke63895
Thank you one and all for the advice. Lots off things to try and will come back with results but it looks like they were cheap ones that came with the lathe. Or another thought could ibe using the wrong tool.
Regards
Gary
9 August 2011 at 18:47 #73092
Martin W
Participant
@martinw
Gary

You suggest that it may be the wrong tool. The only problem with index tipped tooling I have had is using the wrong tip for the material which can affect the finish you get. Ideally carbide is best used to remove relatively large amounts of material quickly but is itself very brittle so can be damaged if the stresses are in the wrong direction.

If you have some HSS tooling then try that as it relatively easy to grind by hand on a standard grey grit grinding wheel. Not only that but one can change the tool geometry to suit albeit fairly crudely.

The index tipped tools I have are made by Glanze with Sandvik or Kennametal tips which were bought cheaply on Ebay. I have used these tips on a variety of materials, not necessarily the recommended ones, and have in general manged to get a reasonable to good finish with them.

Cheers

Martin
9 August 2011 at 19:34 #73094
chris stephens
Participant
@chrisstephens63393
Hi Ian,

I might have been mixing up your bridge with Gary’s problem,OOPS.

As some of the readers of these pages are aware I make a fair bit of my own tooling, it’s so much cheaper than buying. Rather than using car axles, for a number of applications, mild steel is good enough, it’s all a question of size and strength.

For any professional tool users reading this, saving money is more important to me than time, give me the next wining lottery numbers and I will make tool suppliers wealthy men, but until that day home made will have suffice.

As for the tossers who are causing problems over here, let’s not go into that or some might accuse me of not being a liberal minded chap. Dammit, who cares, stun guns, water cannon, snatch squads, CS gas etc are too good for the ungrateful b*****ds.

Now to bring it back to ME subjects, has anyone ever made a model of a water cannon?

chriStephens
9 August 2011 at 23:52 #73104
Martin W
Participant
@martinw
Chris

I haven’t seen a model of a water cannon but I would be quite happy to have them fill a life size one with something more corrosive and aggressive than water for the police to use!!!

Martin
10 August 2011 at 00:38 #73106
chris stephens
Participant
@chrisstephens63393
Reply to Martin sent as a PM to save the blushes of the general public.

chriStephens
10 August 2011 at 09:05 #73108
Gordon W
Participant
@gordonw
To get back to toolholders; – The cheap insert set I bought had screws made from some sort of cheese, replaced them and all is well, except I don’t use them much, break to easy on my sort of turning.
10 August 2011 at 11:23 #73112
Ian S C
Participant
@iansc
Thanks for that Martin, perhaps the root cause could be partly due to the fact that industry has been put off shore.

The reason I used a bit of car axle was to see if I could do it. Done On the mill the same carbide tips that I was building the tool for, it’s a bit beat upnow but still holds the tip secure, and true. I have since then made another one, with a mounting point at each end, but both on the same side of the holder so that one way the tip is on the left facing the chuck, or in the other end, and the tip faces the tail stock.

If the tip is not secured to a flat surface it stands a good chance of breaking the tip, possibly in half. Don’t throw the bits away if it does, you can braze it on a boring bar, or something like that. Ian S C
13 August 2011 at 08:37 #73287
Gary Brooke
Participant
@garybrooke63895
Thank you gents for all the us full advice. I think I’ve cured the problem and we can get on with the model loco you didn’t know you were building.
I would have got back with my thanks early but the boss insisted that Ivey on with domestic duties before playing out.
Regards
Gary
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