Woody.v8
Blue gluer
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- staffs
I'll be making chips tomorrow, so not such a long wait for my blocks!
- Thread starter Kram
- Start date
dieselsamurai
Too many projects not enough time!
- Messages
- 1,653
- Location
- Hampshire
Likewise , very interested to seeing this done as I have a chunk of bar the correct size to make some more
interesting Youtube video of a guy making them and his channels has loads of interesting stuff too
Jelly_Sheffield
Time is an illusion. Lunchtime doubly so.
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- 1,449
- Location
- Sheffield, UK
Made the bodies of some magnetically closed brass pillboxes for a friend.
Turned a 16mm stub on the end of each part for work holding.
The bases were faced 5mm thick, then a 4mm deep center hole drilled and used to face a 40mm wide recess with the boring bar.
The tops were faced 9mm thick, then a 4mm deep step turned to 39.95mm*, drilled to 8mm deep and a 35mm recess faced.
*He originally asked me to turn them to 39.99mm so there was "no slop", I advised that 0.01mm (0.4 thou) clearance was a transition fit, but he wanted to try...
Sure enough when we did a test fit on the first part the two halves would bind up and we had to pry them apart with a knife, a 0.05mm (1.9 thou) clearance gave a nice location fit.
If we do more I think a slightly less tight fit would be desirable, as holding such tight tolerances (less than a thou per part on a 40mm bore/shaft) is excessive for the functional requirements.
Over to the mill, gripping the stub in a hex collet block and a vice stop, each piece had 6×3mm holes drilled 3.5mm deep.
Putting the drill bit in a collet and running at 4500rpm and 0.15mm/rev with the power quill feed gave excellent results (and is scary fast).
I did a test hand feeding the drillbits with the quill and it resulted in noticeably oversized holes by comparison (3.18mm Vs 3.05mm), which was enough to make the subsequent processes less reliable.
He then inserted 3mm dia by 2mm thick magnets with a drop of retaining compound, put tiny slivers of 3mm brass rod on top of each magnet, and peened them into place with a hammer before filing flat and polishing.
You can't really feel the surface finish at the bottom of the bore by touch, but the polishing compound residue shows up the evidence of turning very clearly.
If we do a bigger batch, I will set up one of the drill-bore-turn tools as they have better geometry and rigidity for the cuts...
I'd also consider taking the DRO scale off to mount the cross-slide automatic stops (I used the mounting bolts to fit the scale without drilling) as using power feed for the internal facing cuts would drastically improve the finish.
Turned a 16mm stub on the end of each part for work holding.
The bases were faced 5mm thick, then a 4mm deep center hole drilled and used to face a 40mm wide recess with the boring bar.
The tops were faced 9mm thick, then a 4mm deep step turned to 39.95mm*, drilled to 8mm deep and a 35mm recess faced.
*He originally asked me to turn them to 39.99mm so there was "no slop", I advised that 0.01mm (0.4 thou) clearance was a transition fit, but he wanted to try...
Sure enough when we did a test fit on the first part the two halves would bind up and we had to pry them apart with a knife, a 0.05mm (1.9 thou) clearance gave a nice location fit.
If we do more I think a slightly less tight fit would be desirable, as holding such tight tolerances (less than a thou per part on a 40mm bore/shaft) is excessive for the functional requirements.
Over to the mill, gripping the stub in a hex collet block and a vice stop, each piece had 6×3mm holes drilled 3.5mm deep.
Putting the drill bit in a collet and running at 4500rpm and 0.15mm/rev with the power quill feed gave excellent results (and is scary fast).
I did a test hand feeding the drillbits with the quill and it resulted in noticeably oversized holes by comparison (3.18mm Vs 3.05mm), which was enough to make the subsequent processes less reliable.
He then inserted 3mm dia by 2mm thick magnets with a drop of retaining compound, put tiny slivers of 3mm brass rod on top of each magnet, and peened them into place with a hammer before filing flat and polishing.
You can't really feel the surface finish at the bottom of the bore by touch, but the polishing compound residue shows up the evidence of turning very clearly.
If we do a bigger batch, I will set up one of the drill-bore-turn tools as they have better geometry and rigidity for the cuts...
I'd also consider taking the DRO scale off to mount the cross-slide automatic stops (I used the mounting bolts to fit the scale without drilling) as using power feed for the internal facing cuts would drastically improve the finish.
Whats it for?
Woody.v8
Blue gluer
- Messages
- 4,218
- Location
- staffs
Part of a jig for clamping on to bearing surfaces
