how long is internal bore? full length?
Printable View
how long is internal bore? full length?
Yes full length
That's going to be near impossible to make unless the tolerance on the bore is very loose so it can be made from a bit of tube. to bore out a 25mm OD cylinder 440mm deep is going to need some very specialist tooling. I hope you have deep pockets...
As irving says, machining that depth and that narrow will be abit challenging. You may want to look to see if there's any hydraulic cylinder tubing available in a suitable size.
I had 3 foot of 1.5" diameter steel rod drilled through and honed to 0.5" a couple of years ago.
I forget who did it but it wasn't expensive, I think they used a gun drill, I used Google :beer:
Quote:
Originally Posted by m_c
TBH i think a Swiss/sliding head is the only way to go for this sort of job if accuracy is important.
Hi Robin, yes it can be done, and I'd not thought of a gun drill but it needs specialist equipment. A gun drill and a lathe with a 1m+ long bed to use it isn't something most people here have access to!Quote:
Originally Posted by Robin Hewitt
Premier Deep Hole Drilling Limited - The Deep Hole Drilling Process
Sliding head is all well and good for the OD but I'd agree with RH that a gun drill is needed for the ID for any bit of accuracy. If you started off with a tube with the ID already close enough to the required finished dims then the bore of the tube might keep you in line (with a new drill - symmetrical point angle and both lips even) but not for tight tolerances. You would need a long travel to accomodate the long drill or a gun drill at starting point and the material held either with the rear in the chuck and front on a fixed steady or else the front of the job in the chuck and the rear in a custom collet at the "back" of the chuck, i.e. left side of the machine.
It's quite specialised but for those with the correct tooling it shouldn't be overly complicated. Cylindrical grinding as mentioned previously would be the most cost effective method of achieving the final ODs on the smaller shafts.
Best of luck with it.
Noel.
(Edit: Looks like Irving said what I was trying to say about 2 minutes ago :) )