Horizontal Boring Mill Power Drawbar and a bit of Back Chamfering
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- เผยแพร่เมื่อ 21 ก.พ. 2024
- A video for Max Grant describing the design and operation of the power drawbar on my HBM. Also included at the end is some back chamfering of holes on the HBM.
I bet you was really happy that it had that power drawbar 👍👍👍
Very happy indeed. Without it I would have been looking to do this job on another machine.
That is a good set up on the draw bar . I think i will have to bite the bullet & make a heap of the Bayonet adapters for the NT50 tooling on my mill & keep running it . It's just a bit of a janky method to grab the tools , but works . My one has the electric interlocks & a time delay before it will let you start the spindle . Cheers Ken , Thanks . 👍
For me at least, a power drawbar in a milling machine is just after digital readouts in order of importance. They really do make a difference on repetative operations. Ken
That looks identical to how my DeVlieg jig mills clamp the tools.
🧐 interesting
Thanks.
Excellent description of the de-clutching mechanism. What a great system to prevent whoopsies. The whole system is pretty cool really. And those vise jaws are a interesting concept. Stop pin bores by the looks of things. Did you discuss those in a previous video?
The holes in the vice jaws are actually there to allow you to set parts at different angles. They come with a map that shows you where to place the pins for a certain angle. You then set a part on the pins and tighten the vise jaws and the part will be at that angle. You are right though, in this case I was using it for a stop pin. I made a mistake part way through when I resharpened the large drill and didn't put enough relief behind the cutting edge. This caused the drill to rub severely and this caused a huge increase in drill thrust. The boring mill feed was up to the task and it bent the stop pin before I realized the problem.
That draw bolt system seems robust but a bit complex.
Fine if it’s working as designed.
You must have bought an INT40 holder with M16 thread, still got them?
I thought about just clamping that HSS chamfer tool bit in for retraction through the hole…
Save a second or so but what could possibly go wrong!
Hahaaa.
That HBM has proven useful.
It has proven very useful. I have a large project underway right now and I would estimate 85% of the non lathe work has been done on this boring mill. The more I use it the more I think I should have got one years ago.
Did you make any progress on making up a nose for supporting the spindle yet
I haven't made any progress yet as I have been too busy with a large project. When I get some time I will make one as it seems it would be very handy.
My boring mill uses a MT 4 spindle I wish it had 40 taper . I have thought about making an adapter from MT4 to 40 taper but never got it done and some people said it would not work. Are you looking for 40 stuff ?
Ive got a MT4 to 30 taper on my smallest HBM, i made it to take BT30 holders because thats what i use on one ofnmy mills.
Dont think 40 would work on a MT4 without it being incredibly long
The 40 taper with power drawbar is hard to beat. I pretty much have all the 40 taper tooling I need but I still search on ebay for odds and ends to round out my collection.
The spindle taper looks terrible
While it is in fairly poor condition the video makes it look much worse than it is. After I reviewed the video I went back out and looked at it again because it looked so bad in the video I thought maybe I had missed something. I would estimate that 75% of the original taper is intact and the tools seem to seat properly and work without problem. I've taken some pretty heavy roughing cuts with facemills mounted in the taper and there were no issues. That is why I'm pretty sure this machine had its slideways rebuilt and then had very little use. Most of the alignment checks I did fell within new machine tolerance yet the spindle condition shows this machine has a huge number of hours on it.
Beautiful machine... Scars n all... Mr HMW saw its potential along with its flaws and knew he could overcome.. Thank you for sharing