hi all whats the best method

[michael burton 1Participant @michaelburton1]

[michael burton 1Participant @michaelburton1]

hi all i need to drill a peice of ally to suit 12mm ext dia bearings and a 12mm hole for a tube now the peice is 150mm long these holes need to be as inline as possible i cant drill the whole length the drill and mill is to short……. no i could probley mount it on to a angle plate and do it that way but this also brings a prob the angle plate i have is just the right size to fit my mill table but not wide anough to allow me to put bolts thru it to seure the work piece can i jus use large tool makers clamps the ally is 150 x 50 x 25mm

or would mounting it in the lathe be a better method i did think of doing it this way but was worried about the small clamping area would only be about 25mm on each edge would i get away with this if the lathe is on a slow speed and i feed really slow???????/

i also thort of takeing it to a local engineering firm but i cant afford the labour price

thanks for any help atb mike

[JasonBModerator @jasonb]

Can I ask what is the purpose of the tube?

The way you describe things you need an accurate 12mm hole through the metal, the tube will slip inside the hole and then bearings pressed in at each end?

How close to 12mm is the tube and if needed could it be a fraction smaller?

J

[michael burton 1Participant @michaelburton1]

hiya the tube is a barrel and tbh as i have to machine the end of it it can be smaller, the 12 mm hole needs to be at one end to jus past the middle of the block with a bearing at each end of the 12mm hole to surport a stainless steel rod that is 8mm dia sorry for the lame explanition to start of with but its hard to explain……..

thanks for ur reply

[John HaineParticipant @johnhaine32865]

Toolmakers clamps will be just fine. I use them all the time on an angle plate on my VMB to secure lumps for milling. Latest was 1 inch thick CI block to square up the ends.

[JonParticipant @jon]

Mike 4 jaw chuck.

Make a few extended drills and reamers up.

Drill through around 9 to 10.8mm Larger the better as less likely to flex, keep backing out.

Put an oversize drill through, this will even out a few errors if any.

Ream slowest speed possible with plenty of cutting fluid.

On this tops 5/8", lower is 1/2" through about 8" and from 4" x2" 6082 aluminium. http://pic20.picturetrail.com/VOL15/728921/1723145/20513282.jpg Inserted in is 5/8" and 1/2" silver steel rod and total 3D runout 0.00015" amased me.

[Ady1Participant @ady1]

[michael burton 1Participant @michaelburton1]

done =) was not a complete succses but its done and im happy with it

[Author]

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