making square groove on end of round bar

This topic has 20 replies, 13 voices, and was last updated 24 September 2013 at 17:58 by jonathan heppel.

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23 September 2013 at 10:59 #130513
littlerick
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@littlerick
I need to make a square cut groove that is around 8-10mm deep on the flat edge of a round bar. Like a "O" but i need 3 of them getting smaller.

I thought a parting tool would be best, but now I have snapped to of them, i'm thinking maybe not!

Work piece is an old large steel bolt head approx 41mm now its rounded off,

Any tool that is deep enough to cut, while being small enough not to jam and snap as the cut gets deeper.

Rick
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23 September 2013 at 10:59 #6885
littlerick
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@littlerick
23 September 2013 at 11:12 #130516
Bazyle
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@bazyle
Hacksaw. Several blades to make wider cut.
23 September 2013 at 11:13 #130517
KWIL
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@kwil
How wide is this groove and what kind of parting tool are you trying to use? An drawing would help.
23 September 2013 at 11:31 #130519
Ady1
Participant
@ady1
Stiffness is everything with parting off type operations and try to cut from the back with an upside down tool to help with dig-in problems

Using the backgear can also make things a lot easier
23 September 2013 at 11:40 #130521
jason udall
Participant
@jasonudall57142
sounds more like treppanning than groving…this is a face operation.

what radi? you will probably need one tool for each radi..

hole saw?

and how many?

a home made cutter or cutters might work..turn/bore saw/file harden..

Edited By jason udall on 23/09/2013 11:45:42
23 September 2013 at 11:55 #130522
Sub Mandrel
Participant
@submandrel
Your bolt head will be tougheend. If the job isn't critical, anneal it by heating to a good red heat and cooling slowly.

Take a piece of HSS of the same diameter as your groove's width, make a holder for it and grind the tip away to half thickness for about 1/2 of a diameter distance. provide a few degrees of relief at the end of the cutter and just a smidgin of top rake (only a little so it doesn't dig).

The shape won't jam at the sides, even in small diameter grooves but you will need to go slowly.

It works, I've used one to groove the side of a laser cut flywheel in medium steel.

Neil
23 September 2013 at 12:05 #130523
JasonB
Moderator
@jasonb
At that depth and width you may want something more rigid in which case grind something like this from a 10mm HSS blank
23 September 2013 at 12:17 #130524
jason udall
Participant
@jasonudall57142
NEIL nice

'course I hadnt thought that ….

most I have used have been insert holders..with large ( about 45degree worth) keel for support ..which is what brought the hole saw to mind
23 September 2013 at 12:19 #130526
littlerick
Participant
@littlerick
sweet thanks… i'll try a few ideas n see what works out.
23 September 2013 at 13:29 #130528
Nobby
Participant
@nobby
Support with a centre from the tailstock if you can
Nobby
23 September 2013 at 17:11 #130545
Grizzly bear
Participant
@grizzlybear
Hi littlerick,

A picture would be nice. Confused .com

Regards, Bear..
23 September 2013 at 18:20 #130549
JasonB
Moderator
@jasonb
Sounds like this is whats wanted
23 September 2013 at 19:30 #130553
littlerick
Participant
@littlerick
yes thats exactly what i need… im going to get some tool steel and have a go at making a tool for the job.. main problem is getting it strong enough while at the same time shallow enough not to jam on sides..
23 September 2013 at 20:28 #130556
Grizzly bear
Participant
@grizzlybear
Thank you JasonB for the picture, Impressive. We just need to know what its for. Branding mice perhaps.

Regards, Bear..
23 September 2013 at 22:12 #130565
magpie
Participant
@magpie
41mm bolt head, will have to be BIG mice !!!!!

Cheers Derek.
23 September 2013 at 23:59 #130569
mark mc
Participant
@markmc72333
What about putting it in a rotary table and mill it out?
24 September 2013 at 07:33 #130577
littlerick
Participant
@littlerick
No rotary table yet… in fact tools are limited which is 80% of problem.
24 September 2013 at 07:47 #130580
JasonB
Moderator
@jasonb
Although these show the middle being trepanned out of a plate the tool is similar to what I sketched above except for the rounded end as that was left over from a previous use.

This is 5/8" (16mm) brass cut 8mm from either side

And this is 10mm steel cut just short of 5mm each side then hit it with a hammer and the middle drops out safely.
24 September 2013 at 08:12 #130582
Michael Gilligan
Participant
@michaelgilligan61133
Posted by littlerick on 24/09/2013 07:33:39:

No rotary table yet… in fact tools are limited which is 80% of problem.

.

Clearly then, the suggestions by JasonB et al are the way to go … But, for the future, you might consider buying/making a Milling Spindle on a Vertical Slide for your Lathe.

MichaelG.
24 September 2013 at 17:58 #130612
jonathan heppel
Participant
@jonathanheppel43280
I second the inverted tool suggestion. Also if you're feeding with the topslide, make sure it's adjusted well, including backlash on the screw if fitted, because self feeding is more of an issue when trepanning. Easy on rake angle too for the same reason.
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