Thread: Power Hacksaws V's Bandsaws

Originally Posted by simonl

Although see does understand its appeal to me.

Then you're ahead of most of us I suspect.

Yea the misses is pretty good to me I must say. BUT she is still a woman which still brings with it complexities. She is my most complex machine acquisition!

Well, I bought the Heska. Beat him down $50 and paid $200. I was really up against it as I wouldn't know one end of a bandsaw from the other! I asked what was wrong with it and he couldn't say (he's the office dude) He just said that they were using it one day and it stopped. He then mentioned something about someone looked at it and mentioned about a damaged gear.

Anyway, for $200 I thought it's worth the risk. Got it home and without delay I started taking it apart. I didn't take long to find that in indeed has a gearbox with a worm and gear in an oil bath. It has a sight glass that has a hole in it. Are you guys getting the same picture as me? Slowly the body of evidence comes together!

So I removed the gearbox and then the cover from the gearbox. Not a pretty sight. A lovely paste of gear oil and bronze particles!

Photos show the damage. So I guess I better look into making a bronze worm gear. What a great time to learn. Everything else seems to move well. There is some surface rust but that all it is. I does show signs of coming from a workshop that does little maintenance and affects repairs on a shoestring budget. Lots of silastic around hydraulic connectors and coolant hoses. Yuck!

I got other stuff to do so it will sit there until I'm ready to deal with it. I think that if I fix the gear and give it a nice paint job, I'll at least get my money back anyway.... that's if I don't want it anymore.

2013-05-17_13-22-51_563.jpg2013-05-17_13-21-30_171-1.jpg
It's just what I was looking for. Can't wait to get it into smaller bits!

Cheers,

Simon

"that's if I don't want it anymore."

hahaha...........once you get the bugs outta that beasty you won't wanna part with it

Yea. I'm tipping I might earn my money with this one! I'll blame Michael!

I have since totally removed the worm gear. About 180 deg of it have the teeth completely sheared off, the other side are present but they are folded over. So I am not going to be able to use it to measure. I may have to use the worm to take measurements. I may have to refer to my book on gear cutting by Ivan Law (from memory.. could be wrong) At least it's not helical, that would screw me.... Pun intended!

On a side note, one other question: How do you run a 3 phase machine off a VFD if it has 3 motors? It has the main motor, coolant pump and hydraulic pump. How can you run all 3 off one VFD? Can you? I could (at a pinch convert the hydraulic and coolant pumps to single and use the VFD on the main motor but have/do others do?

Yea I know I'm getting a bit ahead of myself!

Cheers,

Simon

Simon for the coolant pump you could use an old washing machine pump, even a fountain pump from bunnings is pretty cheap.

Put up a couple of photo's of the hyd pump motor and it's spec's.

Simon I think I have a couple of evaporative cooler pumps somewhere, I'll send you one
of them if you want.

Originally Posted by simonl

Yea. I'm tipping I might earn my money with this one! I'll blame Michael!

... At least it's not helical, that would screw me.... Pun intended!
...

Cheers,

Simon

At least that would mean that I would have some greater purpose in life (that is, being Simon's scape goat).
Strangely enough if it were a helical gear I could make one up for you without too many dramas. I've never done a worm gear. Please post (or PM if you prefer) the dimensions of them as it's as good a way to work out how to make them as any.

I can't see why you couldn't run all three motors off one VFD. The only thing to remember is that you could only switch them in and out when the VFD was off - that is, if you decided to not run coolant you would have to turn off the main motor at the VFD, switch the coolant pump out of the circuit and then restart the main motor.
What I would do instead is have a by-pass, so that if I didn't want coolant for example, I could turn a valve that instead of running the coolant into the coolant delivery tube it would run it straight back into the tank. That would keep it aerated too (less smell). I'm assuming that the hydraulic pump has to run all the time, so no problem there. Come to think of it, I have a bottle of (neat) synthetic coolant in the shed - never been opened. Any interest?

Michael

Originally Posted by BobL

I agree they are a long long from a proper vertical metal cutting bandsaw but I'd rather have one than nothing at all especially as I don't have oxy cutting gear in my shed.
For me the worst thing about them is their instability in the upright position especially if you have to put a bit of pressure on the blade.
I know some people sit on them but I prefer to back them up against something.

I had similar problems, so made a new base for mine out of 50x50x3angle that changes the issue of instability, I went about 300mm further back and 100 mm wider, I also fitted castors so that I could move it out of the way or for angle cutting.
Kryn

Hi Shed & Michael,

Shed, that's a very nice offer. I shall keep that offer in mind if I do decide to replace the pump.

Michael, As can be seen in the photos, the gear is quite severely damaged and I'm not sure if any reliable measurements can be obtained from it. I only just got it out and took pics. I have not have any time to take any measurements yet. The worm seems unharmed in the whole process, it's probably hardened but I wouldn't know. Perhaps I can take measurements of the worm and work back to the gear?

I guess the diameter has not changed and I can still count the number of teeth, does that mean I can calculate the modulas and pressure angle?

My first thing I will do is ring the Australian distributor. Actually I just did a quick search for Autralasian Machine Tool Co. and nothing comes up. It's a name plate on the machine but it's old because there's not even a 9 at the start of the melbourne number. So there goes that idea!

Hey Michael, if I send you the blank, do you think you can cut it for me?

So, the coolant pump is sorted..... Too easy that one!

Now the hydraulic pump runs all the time? I assume it's used to manually raise the saw and it just bye-passes (like the coolant pump) when it's feeding & cutting?

Other pic is of the hydraulic pump. 2013-05-17_19-05-37_186.jpg2013-05-17_19-04-25_316.jpg2013-05-17_19-04-17_621.jpg

I'm getting way ahead of myself here. I got so much other stuff to do in the shed...... but this little project is so much more fun!

Cheers,

Simon

As I understand it to get the proper worm wheel form you need to hob it. But according to Law a simple angled spur gear can be used, it just won't run as smooth or last as long. But that's what was in my chinese lathe apron and that's what I plan to replace it with. It would probably still be ok if it had been lubricated and not crashed.

Originally Posted by simonl

Hi Shed & Michael,

...
Hey Michael, if I send you the blank, do you think you can cut it for me?

...
Cheers,

Simon

So first I'm to blame and now can I help? Wow Simon - you really know how to make friends!

Yes I wouldn't mind having a go at cutting one (once I work out how). I think I'd have to make a hob up as Bryan suggests. To start with as well as the number of teeth on the gear I think you'd also need to know major and minor diameters of the worm; the worm screw pitch and the axis to axis distance between the worm axis and the worm gear axis.

Michael

It's time to get that new RT of yours dirty Simon

You could fly cut that wheel, mount the blank on a mandrel parallel to the z axis on your mill,
tilt the head to the tooth angle, plunge the blank into the cutter to the required depth with your y axis then back it out and adjust RT to next tooth ect ect

You would need to make 2 fly cutter's the correct length for the major and minor diameters of the wheel.

eze peezy for a man of your talents

Originally Posted by shedhappens

You would need to make 2 fly cutter's the correct length for the major and minor diameters of the wheel.

Not if you turned a radius on the face of the blank first.

Originally Posted by shedhappens

It's time to get that new RT of yours dirty Simon

You could fly cut that wheel, mount the blank on a mandrel parallel to the z axis on your mill,
tilt the head to the tooth angle, plunge the blank into the cutter to the required depth with your y axis then back it out and adjust RT to next tooth ect ect

You would need to make 2 fly cutter's the correct length for the major and minor diameters of the wheel.

eze peezy for a man of your talents

I like that idea.....the only way i have seen worm gears cut is will a hob mounted in a lathe and the gear blank flat and free spinning on the saddle. You need to rough the blank out and then take the finishing cut with the hob at full depth, you cannot take a rough and finish cut with the hob. If your not exactly on the PCD the gear will just keep spinning round until there is no teeth left......

Well done Simon, I'm almost jealous.....you got one hell of a saw for 1/3 the price i paid for mine...and you get to have some fun bringing it up to scratch.

Cheers
Ew