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21st Apr 2020, 10:01 PM #16Senior Member
- Join Date
- Aug 2011
- Location
- Perth, Western Australia
- Age
- 67
- Posts
- 362
It must be the season for braking parting tools.
Took out a 4mm parting tip on some 75mm mild yesterday.
I was just about to pull out and do a clearance cut as I had to go down to 13mm hole. I heard it change note, retracted and hit the foot brake but to late. Bang.
The bar might be ok. It has not broken out the bottom like they usually do. Fitted a new tip and it looks ok but have not tried it yet.
Went and cut the rest with the drop saw.
Tony
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22nd Apr 2020, 01:02 AM #17
Hi Guys,
FWIW I buy cheap Chinese 2 mm thick by 12 mm wide by 200 mm long HSS parting parting blades at just over £4 for two. You do have to grind them to suit, but they work very well for me. I don't see any point in paying £50 for a holder and then some more for carbide inserts to have them go bang on me !Best Regards:
Baron J.
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22nd Apr 2020, 09:35 AM #18Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
Haven't read the entire thread but the first thing I noticed was the parting tool holder is not perpendicular to the work.
I'm not sure how significant this is with this sort of tool but my experience is doing this with a regular parting blade is asking for trouble.
TOOLLATHE.JPGblade
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22nd Apr 2020, 09:52 AM #19Member
- Join Date
- Feb 2020
- Location
- Albury
- Age
- 58
- Posts
- 90
Pipeclay,
thanks for your inout so far.
Centre height should not of been too much of an issue at the point where the tool broke.
After the bang, when I finished the cut, I noticed the further I got into the material the tool became more "reluctant" to cut and needed more "push or pressure" to bite. When I got to 5mm or less the tool was really reluctant to bite. That's what prompted me to check tool height. After I adjusted to the correct height the tool started cutting nicely with less pressure and I was able to successfully finish the cut.
Did you retract the tool at all during the process?
Yes, I did retract a couple of times prior to the bang.
Is this the first time you have parted solid?
No
Is this the first time you have parted mild?
No
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22nd Apr 2020, 10:44 AM #20Member
- Join Date
- Apr 2015
- Location
- Tungkillo, South Australia
- Age
- 87
- Posts
- 74
I solved my version of this problem about 25 years ago by making and fitting a Rear Tool Post and mounting the Parting Blade (the insert kind) upside down. This way, the 'spiral chip' that parting usually creates now drops out downwards instead of jamming in the parting groove. 10 mm steel plate bolted together as I didn't have a welder then.
CharlesRear Tool Post for Parting.2.jpgRear Tool Post for Parting.1.jpg
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