Author Topic: Lathe tools too high  (Read 9748 times)

Offline Shepherduke

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Lathe tools too high
« on: December 19, 2009, 11:43:54 AM »
  I have at last got my new mini lathe.  I have a problem in that the suggested 10mm square tools I bought are about a mm too high at the cutting point when inserted in the tool post.  These are tungsten tools.  I cannot get them any lower, so is it feasible to put a small shim under the back end of the tool, to bring the height of the business end lower? As they are tungsten, I'm limited as to how much meat I can remove to attain the correct height.  Apart from grinding off the bottom of the tool to lower it, or getting a smaller square section tool, is there another way?
 Your advice welcomed.

Offline NickG

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Re: Lathe tools too high
« Reply #1 on: December 19, 2009, 12:16:39 PM »
Only the tip will be tungsten, do you have a milling machine? If you put a shim under the back it will have a negative rake angle and won't cut well I wouldn't have thought.

Nick
Location: County Durham (North East England)

Offline Bernd

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Re: Lathe tools too high
« Reply #2 on: December 19, 2009, 07:40:53 PM »
I think Nick has the answer. If you have a mill just take off what is needed on the bottom of the tool.
If not, use your tool post to mill the bttom. Make sure the bottom of the tool faces the chuck squarely. Put a mill in the chuck or collet and mill the tool using the cross slide.

Bernd
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Offline NickG

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Re: Lathe tools too high
« Reply #3 on: December 20, 2009, 03:27:58 AM »

Bernd, that's a great idea if you don't have a milling machine - never thought of that!

I've got one of those tool holders and it's too big for my lathe so was thinking of taking a skim off the bottom to make it useable, started but it was made of something hard, will need coolant or wreck milling cutters so am waiting for that.

Location: County Durham (North East England)

Offline Shepherduke

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Re: Lathe tools too high
« Reply #4 on: December 20, 2009, 07:40:05 AM »
 Thanks for all the suggestions.  Unfortunately I do not have milling machine, so reading between the lines I need to remove excess material from the bottom of the tool by grinding.  I suspect it would be easier to solve this problem if I was using HSS tools.
By the way, is it possible to purchase a  stone for a small benchtop grinder to sharpen tungsten tools? I believe they are known as "green" stones.

Offline NickG

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Re: Lathe tools too high
« Reply #5 on: December 20, 2009, 08:48:57 AM »
Actually, It'll be easier to take the metal off with your tungsten tool as only the tip will be tungsten - brazed on. Puting in the tool post with a milling cutter or fly cutter in the chuck means you'll be able to get the bottom of the tool nice and flat, otherwise it'd be all over the place. Yes I believe you can get green grinding discs for your bench grinder for that. Somebody on here said they found some of those cheap diamond discs for dremmels though which worked very well as you should onlyneed to take a tiny skim off the tungsten tip.

Hope this helps.

Nick
Location: County Durham (North East England)

Offline Stilldrillin

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Re: Lathe tools too high
« Reply #6 on: December 20, 2009, 08:57:48 AM »
Actually, It'll be easier to take the metal off with your tungsten tool as only the tip will be tungsten - brazed on. Puting in the tool post with a milling cutter or fly cutter in the chuck means you'll be able to get the bottom of the tool nice and flat, otherwise it'd be all over the place. Yes I believe you can get green grinding discs for your bench grinder for that. Somebody on here said they found some of those cheap diamond discs for dremmels though which worked very well as you should onlyneed to take a tiny skim off the tungsten tip.

Hope this helps.

Nick


Try here, half way down the page......

http://madmodder.net/index.php?topic=963.30


Not used a green grit wheel since. And still on the 1st face!  :thumbup:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!