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Re: holesaw on a lathe

Posted: Thu May 16, 2019 1:22 am
by spro
Hole saw subject; I bought the hole saw package from banggood. Received it rather quickly from "return department" . I examined the rake and edges of the smaller sizes . They appeared to be useful. The largest, 50mm size, had the pilot drill completely rounded over. It appears somebody couldn't even penetrate the base steel. It was rather shallow compared to a hole Saw anyway. The shank is already machined to be smaller than it should be imo . 50mm is fair large with thick cutters and the shank was made to fit a 3-jaw, smaller 3/8 -1/2" chuck.
I bought other items on the same order which arrived later, from a different department. Step Drill set looks very good. I generally like a compressible punch because you get a free unusable washer. These step drills are right nice if you don't( or do) mind the chips.

Re: holesaw on a lathe

Posted: Thu May 16, 2019 10:53 am
by BadDog
I just did this last weekend. I'm making ~5/8" spacers to offset brake backing plates so I can utilize pull off drums on a heavy full float rear axle that OEM used hub/drum assembly (drum pinned to back of hub by studs, very heavy, real PIA for any sort of work). Anyway, once rough cut to size from 3/4" plate and bandsaw edges squared up on the mill, it went to my lathe in the 4 jaw for a 2.5" hole saw. It was a little unpleasant to start, but once the cut was established it cut well even with no chip relief hole, just cleared frequently. It REALLY likes to grab and puts a very substantial torque on the drill chuck driving the saw. I used an 18N on MT4 that was up to the task, but it seemed that the grabby start was right at the limit of what the arbor could handle, and the lathe wasn't going to stall, so failure point would be somewhere in the saw to MT stack, most likely the arbor stem.

My target bore was nearly 4", so I wish I had a larger saw to start, but that's the biggest good quality hole saw I have suitable for steel, the larger ones I would really only use for wood or maybe aluminum.

Re: holesaw on a lathe

Posted: Fri May 17, 2019 7:22 am
by RSG
Nice job Liveboard! Interestingly enough I have to bore some holes in a blast cabinet that are much biller than standard drills and was wondering if a hole saw would do it in a drill! I will have to give it a try.

Re: holesaw on a lathe

Posted: Fri May 17, 2019 7:40 am
by liveaboard
I've used holesaws in drills to cut steel; handheld and drillpress.
After about 1-1/2", handheld is pretty tough.
The drill press works ok, but obviously not as rigid or slow as a lathe. there tends to be vibration and noise. catching and jamming from time to time.
Drilling a relief hole on the cut line really improves things.

Re: holesaw on a lathe

Posted: Fri May 17, 2019 9:12 am
by spro
The pilot drill acts as a register. Sometimes we need replace it with a different drill because the flutes are still cutting the pilot hole. Free hand, hole saw work is similar to how we would use grand dads' and our wood saws. Since your hands are tied up, a dose of cutting fluid first. Just as using a hand saw, the circular blade is worked around the register, applying more force to one side and then another. Intuitive .

Re: holesaw on a lathe

Posted: Fri May 17, 2019 11:05 am
by NP317
Hole saw use on a drill press.
Slooowww and carefully, and well clamped down. Led to success.

Happily, I now have a big mining machine capable of doing that same job.
~RN
2-8-2 SBox Drilling2.jpg

Re: holesaw on a lathe

Posted: Fri May 17, 2019 12:16 pm
by spro
This is so cool ( I say that too much) but really, what is happening. The multitude thin teeth are impressed upon round, yet accurate surface. Sometimes we can't know because there is scale or hardening. The teeth worked hard to get through that, then there is flat platform. The keen edges have been dulled so cutting fluid and back out. Hole saws and stuff gets hot-duh
Altogether you have a large hole and a serious washer/ clamp piece, instead of lb. of chips.
I should comment about the hole saw. Can't go further with that being a Starrett but The shank arbor with definite driver pins means business.

Re: holesaw on a lathe

Posted: Fri May 17, 2019 1:49 pm
by liveaboard
I once saw a morse taper holesaw arbor in a shop.
The price was totally silly; but I still want one.
Every time I use a holesaw in my self tightening chuck, I need to use a pipe wrench to get it loose.

Re: holesaw on a lathe

Posted: Fri May 17, 2019 3:31 pm
by pete
There's a very good reason for that Liveaboard. Self tightening drill chucks according to Albrecht aren't supposed to be used with anything that has a larger cutting diameter than the chucks maximum capacity. There's been a few posts on the PM forums detailing the same thing. The chucks internals aren't designed to take the extra torque larger diameter cutting tools exert on them. The chuck can self tighten to the point of doing internal damage and in severe cases up to the point of destroying the moving parts as well as the hardened and ground fixed internal surfaces. Using that information I've never had to use any tool to either tighten or loosen my Albrecht or Glacern keyless chucks. For the same reason that's why the 1/2" shank Silver & Deming type drills aren't supposed to be used in them either. When you are using those larger diameter tools your supposed to be using a good keyed chuck. None of this is a design fault. There supposed to self tighten if the tool starts to spin. Too large of a tool just makes them self tighten beyond the mechanical limits of what there designed to take.

Re: holesaw on a lathe

Posted: Fri May 17, 2019 3:45 pm
by Harold_V
pete wrote:
Fri May 17, 2019 3:31 pm
The chuck can self tighten to the point of doing internal damage and in severe cases up to the point of destroying the moving parts as well as the hardened and ground fixed internal surfaces.

Using that information I've never had to use any tool to either tighten or loosen my Albrecht or Glacern keyless chucks. For the same reason that's why the 1/2" shank Silver & Deming type drills aren't supposed to be used in them either. When you are using those larger diameter tools your supposed to be using a good keyed chuck. None of this is a design fault. There supposed to self tighten if the tool starts to spin. Too large of a tool just makes them self tighten beyond the mechanical limits of what there designed to take.
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Re: holesaw on a lathe

Posted: Fri May 17, 2019 3:49 pm
by Harold_V
pete wrote:
Fri May 17, 2019 3:31 pm
The chuck can self tighten to the point of doing internal damage and in severe cases up to the point of destroying the moving parts as well as the hardened and ground fixed internal surfaces.
True, that.
I was gifted a 1/8"-5/8" Albrecht that had a cracked hood, apparently due to over tightening. I dismantled the chuck, finding it in good condition otherwise, so a new hood was procured for about $40. I use the chuck, which has a #3 Morse shank, with my Graziano.

H

Re: holesaw on a lathe

Posted: Fri May 17, 2019 4:03 pm
by BadDog
Agreed. That's the whole reason I have a selection of chucks.

The keyless (aka self tightening) are mostly Albrecht, but also a Rohm. I use them for every day straight shank drill bits (only) up to the rated size. Works great. I've got them in sizes and on tapers suitable for lathe (MT4), big drill presses (MT3), and straight shanks for collets in the mill. Sizes include 1/8, 1/4, 3/8, and 1/2".

Then I have the ball bearing chucks. I'm not a huge fan for drills, but love them for heavy stuff like hole saws, large reduced shank drills (S&D), and for taps too. They are strong, and grip very well, even doing adequately for taps that don't have too much torque required. And unlike keyless, they work for left hand drills, and backing out taps when power tapping. Sizes 3/8, 1/2, 5/8, 3/4". The 18N was used for my recent hole saw work. But I don't really care for them for drills without good reason.

So I also have plane bearing chucks, mostly for the drill presses. My 2 big 20" drill presses (a Powermatic and a US made HD Wilton VSG) most typically have a 1/2" Albrecht and a 5/8" Jacobs (3B I think?) respectively, well suited to the purpose of each. My 1/4 Pratt Whitney "sensitive" (weights about 100 lbs) uses a 1/4" old school keyed Jacobs just to minimize wasted space (limited Z).

It took a while to get it all sorted and collected, but I'm very happy with the current selection and allocations. And I've got sleeves that allow the MT3 chucks to serve duty on the lathe as needed. It all works very well. As they say, "horses for courses"