Thread: D Bits & Milling

Thanks for posting this Bruce.

It looks like it worked well.

Regards,

Jayson.

Neat Bruce.

How will you clamp the blade in position?

I have to make another rear post. I bought one of those flimsy idexable carbide parting off blades that I said I wasn't going to buy.

BT

Hi Bruce,

Just read your post, impressive. I think (I'm not sure, thats why I'm asking) you used your Hercus mill? I've read most of yours and AB's posts regarding the little Mills and been impressed with your work on them. You both seem to make the most of the Hercus's limited work space. Hopefully I will soon be the owner of one of these little machines.

Cheers Ben.

Originally Posted by bwal74

Hi Bruce,

Just read your post, impressive. I think (I'm not sure, thats why I'm asking) you used your Hercus mill? I've read most of yours and AB's posts regarding the little Mills and been impressed with your work on them. You both seem to make the most of the Hercus's limited work space. Hopefully I will soon be the owner of one of these little machines.

Cheers Ben.

Ben
Yes I used the Hercus Mill for this job.
They are a small but solid mill for both End Mill operations & Horizontal arbor jobs.
I purchased this mill, used, about 22 yrs ago, & its done a lot of jobs for me.
regards
Bruce

Heres a bit more info on the parting off holder I have just finished machining for the Hercus 260 Lathe.
There has been a lot of discussion about parting off, so decided to do a lot of experiments & trials on parting off & "go back to the drawing board"
Decided to go with a standard 3/32" wide by 1/2" HSS parting blade & make the holder to suit.
The not- so- good a photo of the drawing I did, before making the part, got me thinking about all of the clearance angles clamping method etc.
The blade is held by 3 off 8-32 UNC grub screws. These screws clamp on to the top 20 degree angle on the blade & ensure that its held into the lower 20 degree dovetail machined by the "D Bit" previously mentioned.
Anyway the proofs in the pudding.
First photo shows parting Bright Mild Steel 1" dia, with nice curly shavings.
2nd photo shows parting some 4140 steel BT sent me its 1 1/2" dia. 40mm dia
3rd & 4th photos show the completed holder with grub screws holding blade in position.
5th photo (not so clear) shows the drawing & dimensions.
The holder tested out well & will replace a parting tool ground from a piece of solid HSS I have been using for years.
regards
Bruce

Bruce why the use of the centre when so close to the chuck.

Originally Posted by pipeclay

Bruce why the use of the centre when so close to the chuck.

Peter
I asked myself the same question.
I was getting a little vibration & put it down to the rather hefty 6" dia Rohm Chuck.
Noticed at times before when using this chuck for parallel unsuported turning a slight vibration can develop. The recommended 3 jaw chuck for this lathe is a 5" dia which is quite a bit lighter in weight.
Tomorrow I will try a smaller 4"dia chuck also Burnerd collets & 3C collets.
I do not get the vibration from 3C collet held work.
Its one of those mysteries, but I do suspect the larger chuck could be the problem.
regards
Bruce
ps As soon as the centre goes in to the workpiece the problem is eliminated.

Peter
I just confirmed the previous post about a slight vibration developing with the large 6" dia hefty Rohm 3 Jaw Chuck, (in pristine codition) when parting off without a centre.
When the smaller & lighter 4" dia 3 jaw chuck is used, no problems at all & no centre is needed.
The test piece was 4140 steel 1 1/2" dia.
Regards
Bruce