DIY indexable tooling

[Rik ShawParticipant @rikshaw]

Martin re: DIY indexable tool holders. I have done all of mine using one of these mounted on the mill:

The following applies to a 9mm square insert but of course you will need to adjust for different shapes. With vice jaws parallel to milling table use a centre finder to position quill over centre of shank then drill and tap for insert screw. Next I used 4mm three flute end mill to plunge down the thickness of the tip to provide clearance for the rear 90 degree corner. This is necessary so that only the two sides of the tip bear onto the cut out sides. Its a good idea to elongate this hole towards the rear of the shank by say .025". This will allow a little more flexibility when using the 2mm end mill mentioned next.

Place the tip on the shaft and screw it down and scribe lines where the tip will sit. Mill out the front portion to the tip thickness then using the degree markings on the rotary vice, rotate to obtain the correct 90 degree angle. I used a 2mm endmill to cut the pocket out by eye a little at a time until the hole in the tip nearly lines up with the threaded hole. You don't want it smack on as that little bit "off centre" ensures that the screw will pull the tip hard back into the pocket.

With the pocket complete, apply marker fluid to tip seat, screw tip in right side up and scribe lines at the base of the tip to indicate where the two waste angles can be hack sawed of. Remove tip, dress hack sawed 90 degree with a file – or in my case – a linisher forward facing disc with table rest set level and tool presented at 90 degree to disc.

If the whole process sounds fiddly it is but with only a little practise it becomes much less so. Hope this helps.

Rik

Tip: If you have one of these cheap vices you may know that T slot keys are fitted. It was only when I was making this tool that I noticed that with these keys located in the mill table and the vice jaws clocked square the rotational scale at the base of the vice showed it 3 degrees out.

To rectify this I used a piece of sticky back tape from my thermal label printer. Using a pencil or pen to provide a new pointer on the tape made the line to thick so I gently heated a Stanley blade in a flame and briefly lowered the cutting edge onto the shiny side of the tap – after a few tries the result was a nice dark fine line. The tape can then be stuck over the existing pointer in the correct position. Crude maybe but it does the job!

Rik

[Rik ShawParticipant @rikshaw]

[John Stevenson 1Participant @johnstevenson1]

Couple of points.

If you are not milling the pocket with an angled cutter equal to the angle of the side for support then do a shallow pocket so the unused cutting edges are not butted up to the milled pocket. The clearance hole at the end will protect the tip but under heavy cutting, fretting will degrade the unused edges.

Best to machine the pocket first then mar the hole out with a slightly undersize transfer punch held back the hole in the direction of the pocket.

This will put the hole off centre far enough for the screw to act as a wedge.

[VicParticipant @vic]

Nice job. I've already got a couple of holders so I don't need any more but the beauty of making your own is you can get the height spot on for your own particular Lathe. I've Epoxied shims on mine instead. No need for shimming or quick change tool holders!

[Douglas JohnstonParticipant @douglasjohnston98463]

Yes I always mill out the pocket first before using the undersize spotting punch to get a good tight fit for the insert. I quite often case harden the business end, ensuring the screw thread is filled with chalk powder to prevent the thread becoming brittle. The case hardening is probably unnecessary but I like playing with fire!

You can buy the torx screws on ebay at a decent price but make sure you have the correct diameter as there are a lot to choose from.

Doug

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