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Thread: Power Hacksaws V's Bandsaws
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20th May 2013, 11:17 PM #106Most Valued Member
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Simon the valve on the saw guide, has that got a plunger underneath ? It looks to me like it might
touch a stop underneath that may spool the valve to send pressure to the cylinder after the cut to
automatically lift the head ?
It also has a piece of rod welded on it, will that pull up ? I'm wondering if that is the upsie dowzie control ?
Pure speculation of coarse
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21st May 2013, 12:26 AM #107Senior Member
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[QUOTE=simonl;1650356]Exactly. That's why any gear that ends up in the gearbox will be the second one I make. The fist will be out of plastic! Anyway, making it out of new stock from brass or bronze has now been excluded. I'm not fussed, more than one way to skin a cat. It will happen one way or another, this is all part of the fun!
Check out Peugeot wreckers used to be 1 in Mordialloc and see if there is an old final drive from a 403 404 504 they had bronze worm wheel and steel worm you may find a wrecked 1 there as I before posted about the wrong oil ep 90 eats the bronze the worm wheel may be large enough for you to get a blank at a cheap price just a late night thought Cheers John.
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21st May 2013, 07:21 AM #108Most Valued Member
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Hi Simon,
I'm loving this thread. You have a great team of blokes helping out on this one so I wouldn't be stressing too much. I can't add much but I will be watching with interest. Just make sure you bag and tag everything and keep your camera strapped to your chest . I have taken 664 pics of the Weirs pump so far.
Make sure you keep all of those copper washers as they can be annealed and used again plus I did notice a 'K' type oil nipple in one of your pics. Getting an oil can nozzle to suit them might be the hardest thing you will have to do on the whole project.
Great stuff.
Phil
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21st May 2013, 08:10 AM #109Philomath in training
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One mystery solved! The gauge that you have in post 104 is in feet per minute (fpm) and is roughly what you would expect blade speeds to be for various materials (mild steel is around 90 to 100 fpm from memory)
Shed, that gauge is the reason I think that it must be variable speed that can be adjusted on the go. It would be really awkward to have to stop and change belts, start up check speed and so on. In fact, if you had a series of stepped pulleys you would not need a speed indicating dial.
If the saw has an automatic lift to it, Shed's speculation about the upsie dowzie control could be right - you would expect a valve as far out as practical from the pivot for that. I can't work out the function though as there must be a way of manually raising and lowering the saw. It needs to be up while setting material in the saw but you also don't want it going up full height if you have small stock. If it had raise and lower I would expect 3 ports - 1 to the pump, 1 to the tank return and 1 to the cylinder. The other thing about a plunger for an upsie dowzie valve is how does it reset (that is, saw is cutting, gets right down, hits plunger and raises up. What makes it stop when it needs to rather than just when the plunger is free?)
My bit of speculation -
The loose valve Simon is holding the first pic of post 103 with a top like that looks like it should have multiple turns on it, which suggests speed to me. The valve in photo 4 of that post next to the hydraulic pump looks to be some form of bypass valve, in which case it could be the speed control valve for the ram. I would imagine that once you found a lowering speed that you were comfortable with you would not change it (often). Then again, is it a timer for the saw lift function - the saw lifts until the cavity in the valve is full and then stops?
Michael
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21st May 2013, 09:25 AM #110Most Valued Member
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Hi all,
I have since taken the saw guide off (the one that has a hydraulic line to it) The hydraulics seems to be acting on a plunger and perhaps a spring that produces preload, or some alignment with the guide bearings.
I don't think it's a switch or a reset as such. There is a reset switch on the saw that has an adjustable allen screw that touches the switch when the saw is all the way down. The red button on the right of this "reset" switch resets the switch which can only be done with the saw in the upright position. Phil, Yep I'm starting to bag and tag stuff now. I learnt a while back that zip lock bags and my phone camera are my best friends! Thanks for the advice!
Yep, I'm extremely lucky to have a team of talented and experienced people helping me. My wife cannot believe the amount of resources available & offered to me with such a project!
See pics below:
P5220030.jpgP5220031.jpgP5220032.jpgP5220033.jpg
Cheers,
Simon
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21st May 2013, 10:37 AM #111Most Valued Member
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Simon, the valve that you are holding in your hand, if it only has 2 ports then it has to be a flow
control valve, and it has a modified/extended shaft on it ? To make it more accessible ?
It must be a very low pressure hydraulic system as the valves are made of brass, this could partially explain how the hydraulic system works, and it would not take much pressure in that cylinder to push that head up.
I think that you need to work out how and what the valve does on the blade guide and that most likely will determine what the requirements of the other valves, I can see that it has an adjustment screw on the top beside the T handle, that might adjust the spring tension on a
relief or bypass valve ? Or it might be an adjustable stop for the spool if it has one ?
....clean......disassemble.........foetoez
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21st May 2013, 10:53 AM #112Most Valued Member
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21st May 2013, 11:24 AM #113Most Valued Member
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Hi Simon,
I've been wondering if the valve on the blade guide has feedback from how much pressure is on the blade(from the guide rollers) to control down feed. Seems a strange place to fit the valve if its just a manual control.
Also is there a direction of rotation arrow? your blade seems to be in backwards to the other saw linked to earlier in the thread. This can be a bad thing for worm reductions I'm told.
Stuart
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21st May 2013, 12:20 PM #114Most Valued Member
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OK. I just been to the place where I bought it from to look at their current machine. Same make and similar model.
Here's what I discovered. It too has a 2 speed 3 phase motor, hence the dual scale speed indicated by the arrow/lever. It seems to have a CV pulley system (as Michael suggested earlier) than seems to adjust the speed by changing the tension via a hand wheel. It does not have the hydraulic valve attachment on the guide. It has the same ram setup but it does not raise up electrically with the hydraulics, it has to be manually lifted. The hydraulics merely act as a damper to control the down feed. This down feed is adjusted by the same control valve that I have (the one shown in my hand) There's is attached at the top, just where I think mine should live. Also, to keep the saw in the up right position, this valve must be turned fully CCW which closes the valve and prevents any hydraulic fluid seeping through the ram.
The saw switches off automatically when it is fully down and the cap screw strikes that switch, same as mine. There is no separate switch for the coolant pump, it comes on whenever the motor is running. This is good because it means I can (hopefully) run the main motor and coolant pump together with one VFD. I don't have to separately switch motors.
The hydraulic pump on mine I think is a little different. I have an upper and lower limit switch on my saw which they did not have. I also have 2 extra switches on my saw. I wondering if the switches operate the hydraulic pump to lift the saw all the way until it hits this upper limit switch?
All will be revealed when I remove the covers of the switch gear......
The only issue I have with running this thing on a VFD is the hydraulic pump. If it needs to be switched on/off separate from the main motor & coolant pump then it's going to be interesting. I guess I really have two options.
Option 1: Just convert it to manual operation and not use the hydraulic ram. Not very cool, I got extra features that I don't get to use!
Option 2: Change over the hydraulic motor to a single phase motor and still switch it with these limit switches. The hydraulic motor looks pretty easy to replace. It's about 90W and I just happen to have a similar sized motor, at 150W which is not doing anything.
So far, I think I have worked out everything except what the valve does on the blade guide....
I'm still getting a bit ahead of myself since it's still minus a worm gear. Perhaps we do need to re-name this thread.
Repairing my Heska?
Fixing my band saw?
In search of a (bronze) worm farm?
Also, I found some bronze in the scrap metal place called Highett Metals. They had heaps of bronze. They had a lovely piece that was 5 1/2" diameter and 1 1/2" inner. This would do nicely but it was a 20cm length and they were not prepared to cut it. At 20Kg they wanted $267 + GST which is just shy of $15/Kg. Actually not too bad in terms of $/Kg! I just need to find a small enough piece and it may be the go.
Cheers,
Simon
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21st May 2013, 12:48 PM #115
Hi there,
I was browsing this thread and following your repairs and happened to do a couple of searches for information, I found some information where someone had a Heska vertical bandsaw and found out it was made by another manufacturer and sold under the Heska brand.
When I did a 260 HA Bandsaw search I came up with the Jaespa brand.
I found manuals here : IJS Service Manuals
and a manual for a 260 here : http://www.ianjones.com/pdfs/JAE-W260_SERV-20.pdf
I may be totally off track and you will need to compare to the machine in front of you but I hope it may provide some help.
Regards Dave
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21st May 2013, 12:50 PM #116Most Valued Member
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Hi Shed,
I really don't see any way that the speedo was connected in it's current form? I'm not sure how fancy I want to get with this rebuild to be honest. If I go down the track of a VFD, then a simple POT with a scribed (roughly calibrated) scale behind it will probably do for me.
I tend to go overboard sometimes and I'm thinking I'll just keep it simple.
Hi Stuart,
Do you think it's like a fail safe in that if you set the down feed too fast, it puts extra pressure on a spring and then moderates the flow of the hydraulics, separate from the manual down feed valve? Like a feedback system?
Cheers,
Simon
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21st May 2013, 02:34 PM #117Philomath in training
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Well done Dave - very useful information.
Michael
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21st May 2013, 02:49 PM #118Most Valued Member
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21st May 2013, 03:20 PM #119Most Valued Member
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21st May 2013, 05:43 PM #120Most Valued Member
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In amongst those manuals supplied by Droog there appears to be a control valve that might just do what Stu suggested, http://www.ianjones.com/pdfs/JAE-W320_SERV.pdf pg 28 item 7.
The top of the blade must push on that circular thingo at the top of the blade guide http://www.woodworkforums.com/attach...s-p5220031.jpg brgs that in turn pushes a plunger that closes the ball valve, I'm guessing that the pressure is then restricted to slow the decent of the blade ? It is still hard to tell ? This diagram has a much more complex pressure control valve than Simon's, his only has in and out
eagle eyes Stu strikes again
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