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View Full Version : Bandsaw hydraulic damper, $12



Evan
08-28-2007, 07:54 AM
After seeing that nice looking cyclinder and the price :eek: recently in another thread I decided to figure out a cheaper way. This is what I came up with.

http://vts.bc.ca/pics2/sawdamper1.jpg

It works quite well. I still use the old spring to balance some of the weight but the jack prevents both free fall or cutting too fast in cases where the cut transitions to thinner material. The jack was about $12 new and only a few bits of scrap steel were required to mount it. It isn't very pretty but it works.

The jack happens to have a one way valve that allows the cyclinder to fill almost immediately if the jack is extended by pulling out the shaft. The spring was wound on my lathe from some music wire.

The top of the jack shaft is fitted with an adjustable (and removable) bolt that I polished up to make it slide easily on the white piece of HDPE on the tab that engages the jack.

http://vts.bc.ca/pics2/sawdamper2.jpg

I not too long ago posted a thread about an oiler I made for the bandsaw. I soon discovered a simple way to ensure that the blade was always being oiled but without fiddling with the hose. I have it set to drip on the rear blade guide which effectively transfers oil to the blade. This is much easier than trying to position the oiler over every piece that is cut.

http://vts.bc.ca/pics2/sawoiler1.jpg

lazlo
08-28-2007, 09:13 AM
Looks good Evan. I've been wanting to find a hydraulic cylinder for my bandsaw, but they're so damned expensive.

Evan
08-28-2007, 09:33 AM
It's not as predictable as the real thing but it does stop blade damage and overload. I decided to put it on when I recently changed the blade and the same day accidentally dropped it a few inches on the work and broke a couple of teeth off an expensive bimetal blade.

I had to fiddle with it to get the angles just right and it must have something slick for the ram of the jack to slide on. I think I may go a step farther and make the jack swivel at the botom with a real link at the top. The jack itself is very predictable once set although the adjustment is quite sensitive. I'm going to look at that this morning to see if I can reshape the needle valve to make the adjustment less sensitive.

Your Old Dog
08-28-2007, 09:52 AM
Looks good Evan. I've been wanting to find a hydraulic cylinder for my bandsaw, but they're so damned expensive.

Boy it would sure be nice if someone could cough up some plans for one of the commercial type. I'll bet nearly every hsm'er with a bandsaw would be looking to make one. Is there that much complexity in the type of hydraulic cylinders used for the purpose that they can't be home made?

Pretty cool project Evan. Why did you mount the oiler as it leaves the work as opposed to when it enters the work? Are you only oiling the outside roller?

I also like the coat hanger wire (just presuming its coat hanger) wrapped on the rubber hose too !

Evan
08-28-2007, 10:04 AM
Why did you mount the oiler as it leaves the work as opposed to when it enters the work? Are you only oiling the outside roller?
There isn't a practical way to mount it so it oils ahead of the work. Mounted this way it automatically stops oiling when the saw is raised and is easy to fill too. It oils the center guide bearing that controls the blade height. It really doesn't matter when the blade is oiled as long as it has some oil on it. It doesn't need or use very much at all.

The wire is 14 gauge copper, coat hanger is not flexible enough.

Scishopguy
08-28-2007, 11:51 AM
Evan,

Great idea! It never dawned on me to use a cheap hydraulic jack for a down feed. As for the oiler, you could have the oil flow into a piece of sponge, used as a wiper, on either side of the blade. Kalamazoo had a wiper setup on their small horizontal saws to keep chips from making the trip around the drive wheel. It was a metal clip, just behind the roller guides, that held two one inch square short bristled wire brushes. You could make a little cage to hold a square of sponge material with a little slice in the middle that straddled the blade. Should work like a champ.

BobWarfield
08-28-2007, 02:53 PM
But Evan, where's the nifty knurled brass knob you machined up for the valve to make it easier to fine adjust while things are in motion without groping around for the jack handle?

It's a nifty idea, but to tell the truth, I prefer weight or a spring to the hydraulic cylinder. I used a cylinder on the brand new and very nice industrial bandsaw at the local college's welding shop. I found the valve to be really finicky: all the action was in about 1/8 to 1/4 of a turn. My experience with hydraulic jacks is similar.

Reading on the Yahoo Group for the saws, I was initially caught up in the Great Search for a Cheap Hydraulic Cylinder. Then I noticed several guys commenting that if you just got you saw adjusted properly, springs or weights work great and weren't so finicky. Having tried both, I wound up agreeing wholeheartedly.

Of course after using the bandsaw for a year and a half, I but a Multicutter (poor man's cold saw) and now the bandsaw gathers dust:

http://www.thewarfields.com/cnccookbook/img/TurnersCubes/P1203700.JPG

Eventually I will make a little table and retire the bandsaw to cutting curves and lines that are too tight for the Multicutter.

Cheers!

BW

tattoomike68
08-28-2007, 03:19 PM
The one at work looks like it was made from a grease gun tube with a one way valve in the piston and a needle valve to let it lower slowly and bypass. Its been working for 25 years.

Evan
08-28-2007, 10:54 PM
It's a nifty idea, but to tell the truth, I prefer weight or a spring to the hydraulic cylinder. I used a cylinder on the brand new and very nice industrial bandsaw at the local college's welding shop. I found the valve to be really finicky: all the action was in about 1/8 to 1/4 of a turn. My experience with hydraulic jacks is similar.

I tried it set to slow motion without the spring engaged. No dice. Without a bypass release there is no way to bring the saw to the work in a reasonable time. I am using it with some spring support and the jack set to lower the blade at about 3 inches per second. This seems to work well and prevents the blade from crashing the work if I drop it. Even though it is set fast it still helps a lot with the cutting when the blade goes through something like thin wall square tube. It takes a long time to cut the flat and then suddenly its on the vertical walls and tries to hog them out. The damper stops that and the cut is very reasonable.

The needle valve IS very finicky. I checked it out and the reason is because the end of the needle is truncated. I will have to make another with a full needle and that should give much better control.

Ken_Shea
08-28-2007, 11:01 PM
all the action was in about 1/8 to 1/4 of a turn

Bob, Evan
Just add a turning lever with about a 4" arm.

I used a window crank from one of the old crank out windows, no problems now.



Ken

gzig5
08-28-2007, 11:17 PM
Is there any reason a pnuematic cylinder can't be used in place of the spring or a hydraulic cylinder on these little horizontals?

Ken_Shea
08-28-2007, 11:22 PM
Pnuematic cylinder's do not opperate in a positive manner, in other words, starting and stopping is not positive but spongy. Air compresses, oil does not

Joel
08-28-2007, 11:35 PM
This knob handle has turned out to be a pretty handy mod. I have a lever handle on the engine hoist.

http://img.photobucket.com/albums/v186/JoelinTX/Press1.jpg

http://img.photobucket.com/albums/v186/JoelinTX/Press2.jpg

Ken_Shea
08-28-2007, 11:41 PM
I like that Joel, same princiapl just cooler looking.

Installing my lever, I removed the pin from the valve, drilled the lever and replaced the pin through the lever, so it is tight and I won't lose it :)

Evan
08-29-2007, 01:15 AM
I also had that idea except I am going to use a water faucet handle.

Sparky_NY
08-29-2007, 08:59 PM
Pnuematic cylinder's do not opperate in a positive manner, in other words, starting and stopping is not positive but spongy. Air compresses, oil does not

Very true but a pneumatic (air) cylinder does work nicely for this application, the trick is not to use air ! I used a air cylinder on my 4x6 bandsaw and vegetable oil with a fine thread gate valve for speed adjustment. A very lightweight oil is needed or it operates too slow and adjustment is too touchy. The cylinder I used was 2" bore which I got on fleabay for $15 brand new. I later changed the oil to good old WD40 which is even lighter yet and works even better. Air cylinders won't take normal hydraulic pressure but in this case they work fine and available real cheap.

snowman
08-29-2007, 09:34 PM
I sent someone on here a needle valve...did that person finish their project? Just curious to see. I need to do this same thing to mine probably tomorrow, as I just noticed yesterday that my spring broke and I have a large job coming up.

A large job with a 4x6 bandsaw...isn't that funny!

gzig5
08-30-2007, 12:14 AM
Sparky,
I thought about filling it will oil (was thinking ATF) after Ken gently reminded me of what I already knew. :rolleyes: I've got a 1" bore with 2" stroke cylinder on hand. Do you think that will work? Did you mount yours like Evan did, or just replace the spring, inline with the handle?
Greg

John Stevenson
08-30-2007, 03:58 AM
Very true but a pneumatic (air) cylinder does work nicely for this application, the trick is not to use air ! I used a air cylinder on my 4x6 bandsaw and vegetable oil with a fine thread gate valve for speed adjustment. A very lightweight oil is needed or it operates too slow and adjustment is too touchy. The cylinder I used was 2" bore which I got on fleabay for $15 brand new. I later changed the oil to good old WD40 which is even lighter yet and works even better. Air cylinders won't take normal hydraulic pressure but in this case they work fine and available real cheap.

I have seen this done many times and it works fine, also looks good and neat.

I no longer have a small saw, I had one and it did sterling work, probably did more that the other machines put together but I had the chance of a larger one and took it.

The one I have now has a hydraulic damper as standard and it works fine. The problem with this saw it's you need to be on two sides at once and hold the arm up.

I fixed that by fitting an air cylinder along side the damper. When the cut has finished and it hits the stop switch a second contact block operates a solenoid and the air cylinder pushed the arm up letting you feed the new stock in.
When the start button is pressed it sends the solenoid the other way and releases the air allowing the arm to drop onto the damper.

A simple bowden cable limits how high the arm lifts to save time on the down stroke.

I can get some pics if needed.

.

Davek0974
08-30-2007, 04:45 AM
This is blooming excellent!

I have a 4x6" which i am very pleased with but i cut a lot of box section so it's the old 'slow-quick-slow' cut that causes trouble, buggered a few blades.

I also use air cylinders at work and was just getting around trying one on oil, needle valves with quick return are easy to get, small reservoir and its away. I dont agree with springs as they dont control the fall rate just weight.

I had also thought of modifying a car damper unit, or grease gun, but had not thought of the humble jack.

I have seen plans but it calls for very smooth internal bore 2" tube, i cant find any.

Nice one.

Dave

Evan
08-30-2007, 07:12 AM
Dave,

Keep in mind some of the limitations I stated about the current setup. I recommend going to the extra work of designing a simple link mechanism for connecting the top of the jack to the saw rather than the sliding block/spring system I have so far. I intend to do that myself in the next few days as well as improve the needle valve.

If you want to make your own cylinder you need what is called "hydraulic cylinder tubing".

Ken_Shea
08-30-2007, 09:32 AM
after Ken gently reminded me of what I already knew :rolleyes:

Sorry Greg, I have no skills in mind reading.

BTW, once it is filled with oil it is no longer is a pnuematic cylinder, but of course, you already knew that :rolleyes:

;)
Ken

gzig5
08-30-2007, 10:16 AM
after Ken gently reminded me of what I already knew :rolleyes:

Sorry Greg, I have no skills in mind reading.

BTW, once it is filled with oil it is no longer is a pnuematic cylinder, but of course, you already knew that :rolleyes:

;)
Ken

Your skills are improving, I did know that. Please stay out of my head on the weekends. You may not like what you see...:eek:
Greg

Ken_Shea
08-30-2007, 10:39 AM
Your skills are improving

Well "You Know" what they say, practice makes perfect.


See ya on Monday :D

Ken

Sparky_NY
08-30-2007, 11:53 AM
Sparky,
I thought about filling it will oil (was thinking ATF) after Ken gently reminded me of what I already knew. :rolleyes: I've got a 1" bore with 2" stroke cylinder on hand. Do you think that will work? Did you mount yours like Evan did, or just replace the spring, inline with the handle?
Greg

Cylinder size is a trade off. The larger the bore/stroke the more oil that flows and the less touchy the valve for speed adjusting. The larger the cylinder the more friction the piston/seal has and because we are not talking a lot of force it can get "sticky" causing jerking as it comes down.

Rethinking my efforts, I would say a small bore with a longer stroke would be the hot ticket. Of course the mechanics come into play, it has to fit and have enough stroke to lift the saw upright and still make it all the way closed.

My guess.... 1" bore would be nice but the 2" stroke will be a too short to allow mounting in a way that allows full open and full closed of the saw, also that bore/stroke isn't much oil which will make the valve setting very touchy. I think something in the 4"-8" stroke would work well.

Food for thought..... I have seen mention of using a screen door closer. Might be something worth playing with if you have one around. I have also seen automotive shock absorbers considered for this use.

Lastly, from mistakes I made..... the hydraulic pressure, although low still is around 200 psi I would guess. Plumbing lines have to take some pressure so plastic tubes and such may burst or leak (a mess!) I ended up using 3/8 soft copper with flared fittings. 1/4 copper was just too restrictive and made it hard and slow to lift the saw up after a cut, it worked like a needle valve. The plumbing connections to the actual cylinder have to be flexible because the cylinder pivots during the cutting stroke, copper tube fractured at the fitting after many cycles. (power steering hose?) Another point, there needs to be a check valve mounted in parallel with the needle/gate valve so that the flow is unrestricted in the direction for lifting the saw back up after a cut, otherwise the lift rate is the same as the downfeed rate!

A small resevoir is necessary because the hyrdaulic cylinder holds different amounts of oil extended vs. collapsed due to the area of the shaft. I used a piece of 1-1/2 pipe nipple with a cap on one end and a reducing bushing to 3/8 pipe thread on the other for a resevoir.

pcarpenter
08-30-2007, 12:11 PM
Sparky-- I think that typically a double-acting cylinder is used which precludes the need for a reservoir, flex tubing, etc. The fluid movement from one side of the piston is just directed to the other side of the piston, making the cylinder a closed-loop.

There are needle valves available with the check valve built in...another item that makes plumbing much easier. They allow open flow one direction and metered flow the other. I found some at McMaster Carr.

Anyone know if you could safely drill into a gas pressurized auto shock on both ends to make a double acting cylinder? I would hate to end up with injection poisoning from high-pressure hydraulic fluid.

In the mean time, I was given a whole unit off a very large Grizzly saw. The top of the shaft had broken off at the weak point where the cross hole was bored in the shaft. The shop it was in had replaced them twice and then finally changed the mounting bracket which was a poor design... the angle of the cross pin that connected the shaft of the cylinder to the saw was not at all square with the hole in the shaft. This applied a lot of leverage to the shaft at the pin location and eventually broke it.

In any case, I hope to either use this cylinder or at least the needle valve and plumbing. The cylinder may be a bit too big, though as that saw is huge compared to my 4x6.

Paul

Evan
08-30-2007, 03:53 PM
Don't anybody run out to the shop and build the system I posted above. I have a new and much improved design using the same jack. The old one sucks compared to the new one. As soon as I finish tiddling up the pics I will post it in a new thread so it doesn't get missed.

IOWOLF
08-30-2007, 04:38 PM
Higher , better , faster?

I know guys like that. :)

MGREEN
08-30-2007, 06:13 PM
Don't anybody run out to the shop and build the system I posted above. I have a new and much improved design using the same jack. The old one sucks compared to the new one. As soon as I finish tiddling up the pics I will post it in a new thread so it doesn't get missed.

Too late!
Already started.
This is the band saw I picked up at a yard sale several years ago,
and of course it was missing the cylinder.
I always just stood there and used my hand to feed it.
http://i34.photobucket.com/albums/d140/MIKEGREEN555/DSCF0716.jpg
I made up this part last night to connect to the upper casting
and to the screw extension of the jack.
http://i34.photobucket.com/albums/d140/MIKEGREEN555/DSCF0717.jpg
Then I made a mounting bracket, drilled and tapped holes
in the bottom of the jack,bolted it to the jack,
drilled a hole in the bracket side, and slid
the assembly onto the pin shown in pic # 1
on the side of the lower casting.
http://i34.photobucket.com/albums/d140/MIKEGREEN555/DSCF0719.jpg
The valve is very crappy, I'm going to keep my eye
on this thread to see what the solution might be!
Mike Green

Sparky_NY
08-30-2007, 09:28 PM
Sparky-- I think that typically a double-acting cylinder is used which precludes the need for a reservoir, flex tubing, etc. The fluid movement from one side of the piston is just directed to the other side of the piston, making the cylinder a closed-loop.


Paul

You are correct that a double acting cylinder is required, however wrong on the rest. The volume on one side of the piston is different than the other side because the output shaft reduces the volume on that side of the pistion. This is the same reason hydraulic cylinders produce more force pushing than pulling, in the pull mode the area of the output shaft reduces the piston area and thus the force developed, this also causes different speeds retracting and extending (assuming the same GPM flow rate). Because of the different volumes on each side of the piston the excess oil has to go somewhere when the cylinder is fully retracted, thus the need for a small reservoir.

Take a coffee can, fill it with water, put a shaft in, the water overflows.... the shaft changes the volume, same idea with a cylinder.

PS There is a Yahoo group devoted to import 4x6 bandsaws with much info and pictures of hydraulic downfeed mods and other extremely useful mods. Unfortunately, the most common hydraulic downfeed mod used a surplus special cylinder with built in reservoir, check valve and needle valve which is long since sold out and not available, other systems are shown though.

Evan
08-30-2007, 09:40 PM
You are correct that a double acting cylinder is required, however wrong on the rest.

Some double acting cylinders have a ram that extends out both ends.

http://vts.bc.ca/pics2/cylinder1.jpg

Evan
08-30-2007, 09:49 PM
A double acting cylinder isn't required. All that is needed is a single acting cylinder with room above the piston for the amount of oil that will be displaced and an air bleeder to accommodate the volume change. On the down stroke the oil is pumped through a needle valve externally to above the piston. On the return stroke the oil is pulled back into the lower compartment through a check valve in the piston.

black powder
08-30-2007, 10:49 PM
Evan
you need a reservoir to hold the excess oil ,when when the rod is pushed into the cyl.On your jack the oil is pushed into the reservoir built into the jack ,it is a double wall construction with the hyd .cyl .the inner tube .No oil is on the rod end of the jack,The reservoy is the area between the outer wall and the hyd. cyl . tube. when using a single or double acting cyl. an outside reservoir or a doubled wall construction needs to be used.

Evan
08-30-2007, 11:51 PM
you need a reservoir to hold the excess oil ,when when the rod is pushed into the cyl.

The cylinder is the reservoir.

http://vts.bc.ca/pics2/cylinder4.jpg

John Stevenson
08-31-2007, 03:01 AM
You don't need a resevoir.
True there are differences between the two sides given the rod volume but if you use a cylinder where the stroke used is less than the piston travel there will be room for the excess.

All it needs is a double acting cylinder with the rod attached to the frame and a one way check valve piped between the two ports.

A one way check valve allows fluid to be regulated in one direction but be full open in the reverse.

In use you pipe this up and fill the cylinder up carefully then seal it off with the check valve.
It may require a few operations to get the remaining air to settle out but it will work.

Many have been done this way plus's are cylinders are cheap to scrounge, easy to mount, many come with hardware, all fittings are off the shelf, no having to strip or modify a piston and they look neat and not like your saw has been run over by an 18 wheeler.

Sparky_NY
08-31-2007, 08:29 AM
Some double acting cylinders have a ram that extends out both ends.

http://vts.bc.ca/pics2/cylinder1.jpg

True but not exactly common and would only complicate mounting issues in this case. There are speciality cylinders out there, even ones made especially for band saw downfeeds (ie a replacement part) but the concept of this thread is making one using easily available components and above all cheap.

Evan
08-31-2007, 08:42 AM
but the concept of this thread is making one using easily available components and above all cheap.

Uh, yeah. It's my thread. :rolleyes:

The point is that there are ways to make a cylinder that doesn't need an external reservoir. It isn't that hard to make one but I used the jack because I am lazy. I have many other things to do and winter is approaching quickly.

black powder
08-31-2007, 10:36 AM
Evan
As usual I over looked the obvious , Not used to cyls.not full of oil on each end.

Sparky_NY
08-31-2007, 12:50 PM
Uh, yeah. It's my thread. :rolleyes:

The point is that there are ways to make a cylinder that doesn't need an external reservoir. It isn't that hard to make one but I used the jack because I am lazy. I have many other things to do and winter is approaching quickly.

Yep, hopefully you will finally end up with something useable. Jacks have a lot of friction, not a issue with heavy loads (2 ton rated) but becomes a real problem when its only 50 lbs or so, unless you plan to pump the jack until the saw is back upright... LOL

Evan
08-31-2007, 01:01 PM
Funny. It seems to work great. It does have a check valve so all you have to do is raise it and it fills with oil immediately. As for the load, did you notice how short the lever arm is? On the down stroke it's smooth as snot on a glass doorknob, and that's with the saw turned off. With the saw on the vibration ensures it won't stick.

[edit]

I should show the revised version as in the other thread in case somebody is reviewing this someday.

http://vts.bc.ca/pics2/damper2.jpg

http://vts.bc.ca/pics2/damper3.jpg

BadDog
08-31-2007, 02:48 PM
Might make it easier to adjust if you add some weight to the end of the lever. Wouldn't take much with that lever, so not a huge burden on manual lift.

Evan
08-31-2007, 08:11 PM
It's not a real issue since I modified the needle. It's not as easy to adjust as I would like but it's better than it was. I will continue to fiddle with it until it's to my liking but for now it works well and I won't be knocking teeth out of new blades again. I also like it because it will balance in the 45 degree position and I don't have to reach so far to bring it back on the work. For me reaching at full arm extension often causes blinding pain.

John Stevenson
08-31-2007, 08:29 PM
For extended blade life on these saws there is a quick mod but only if you don't use the vertical cutting facility.

The blade on these travels front to back, cutting against the fixed jaw of the vise. It's like this so when the vertical plate is fitted it pulls the work onto the plate.

IF you don't use this vertical facility then you can twist the blade round so the teeth face back to front, reverse the motor so the blade cuts from the back to the front against the moving jaw.

The reason for this is that normally if the blade jams because it's at an angle pointing down it will dig into the work making the jam worse.

When it's reversed if it tries to jam the blade is facing uphill and will try to kick out the cut and save the blade.

We found this out some years ago when working on some big 36" diameter saws for cutting runner and riser pipes on oil rigs.
A couple of months ago i called in the steel stockholders to pick some bar up and all their latest all singing, all dancing CNC saws were setup to cut this way.

.

Evan
08-31-2007, 11:55 PM
John,

I would be concerned that the cutting drag force, which can be quite high, would cause the movable jaw to flex away from the fixed jaw. When it is pulling toward the fixed jaw the movable jaw has a much easier time holding as it is then the part of the work farthest from the blade that levers in disadvantage against the movable jaw left edge using the blade end of the fixed jaw as a fulcrum. Running backward there is no disadvantage in leverage and the full drag force comes to bear on the movable jaw closest to the blade.

John Stevenson
09-01-2007, 03:59 AM
Evan,
Not really relevant.
You only have a movable jaw when setting up and the machine isn't running.
When cutting with stock in you have two FIXED jaws, if not then you haven't tightened the vise :D

As I say this mod isn't for anyone if they need to vertical cut.
My large bandsaw that can handle 13" diameter or 12" x 18" rectangular came with a missing blade and motor amongst other bits.
I got this running and set it up in the 'normal' way but had problems with it grabbing unless I used very fine blades.

After doing work on the aforementioned bandsaw and having a lot to do with Lennox technical who made blades specially for this saw, 2" wide and varipitch 1 to 1-1/2" tipped teeth per inch, each tip smaller than a match head ! I swapped the blade and direction, also fitted a 4 / 6 tooth varipitch blade which I use for everything except very thin tubing under 1/8"

I now get about 9 month out of a blade instead of about 3 or 4.
This is in a commercial environment and when it gets cleaned about every three month just the chips get shoveled into a 5 gallon bucket that's not easy to lift.

A saw is one of the most underrated tools in a job shop, always there, never appreciated.

As I mentioned in my previous post all the modern saws seem to work this way.
It also gives a lot more chance for the chips to get clear of the blade before going onto a roller, the generic 6 x 4's only have a couple of inches before it's inside the cover.

.

Evan
09-01-2007, 06:10 AM
When cutting with stock in you have two FIXED jaws, if not then you haven't tightened the vise

There isn't any facility to "tighten the vise" on a 4x6 other than the lead screw. I often use a C-clamp to apply more positive pressure to the vise. I can see that technique working well on a larger more rigid machine but don't think it would be a good idea on a standard 4x6 saw.

John Stevenson
09-01-2007, 06:50 AM
There isn't any facility to "tighten the vise" on a 4x6 other than the lead screw. I often use a C-clamp to apply more positive pressure to the vise. I can see that technique working well on a larger more rigid machine but don't think it would be a good idea on a standard 4x6 saw.
Is this the 'same' leadscrew I have seen fitted to every other vise I own ?

You have just changed into splitting hairs / pedantic mode 'again'

If you don't want to accept the idea then fine but it's not unsafe as many high end manufactures have proved [ unless you cut the cord :D ]

.

Evan
09-01-2007, 08:17 AM
Sorry John but we aren't on the same wavelength. I'm talking about a 4x6 saw only. What I mean by tightening the vise is a bolt or similar to clamp the jaw to the table independent of the bolt to the lead screw nut. The leadscrew bolt isn't all that effective, at least not on mine. The movable jaw can still be moved as it will pivot around the bolt. As well, repeated use of that bolt will likely eventually wear out the threads in the leadscrew nut. What it needs is a separate clamp bolt traveling in the leadscrew slot with an arced slot in the jaw base. But then it would be more costly.

snowman
09-01-2007, 03:53 PM
you have to modify the jaws on that saw for it to be worth a dang anyway...simply welding some reinforcement on the jaw will go a long way

MGREEN
09-01-2007, 07:01 PM
It's not a real issue since I modified the needle. It's not as easy to adjust as I would like but it's better than it was. I will continue to fiddle with it until it's to my liking but for now it works well and I won't be knocking teeth out of new blades again. I also like it because it will balance in the 45 degree position and I don't have to reach so far to bring it back on the work. For me reaching at full arm extension often causes blinding pain.
Evan,
This is what my factory "needle" looks like with it's 1/4" ball.
modeled after your mod, this what I did.
It's made from a 10mmx1.5 bolt.
http://i34.photobucket.com/albums/d140/MIKEGREEN555/DSCF0725.jpg
Here are some specs, if you like.
http://i34.photobucket.com/albums/d140/MIKEGREEN555/DSCF0726.jpg
I threaded in the bolt to find the spot where it seated
and then marked the bottom or 6 oclock position on the
head of the bolt, then removed it and welded on an old bent handle.
http://i34.photobucket.com/albums/d140/MIKEGREEN555/DSCF0728.jpg
It works much better than the factory set up, still a very
small movement of the handle to adjust but much better control.

Thanks for your idea!
Mike
Forgot to mention that the new longer tapered section
negates the need for the ball, and simply replaces it.
Mike

snowman
09-01-2007, 07:55 PM
Which way does your compound swing Mike??

J Tiers
09-01-2007, 09:43 PM
The factory one on my Atlas (not Crapsman) version works very well indeed.

If the small amount of turning to cover the useful range bothers you, then make a taper nose that just includes the last part of the taper, stretched out over the full distance that a turn covers. "Shutoff" should be at one end, then the useful range should be spread out over more of a turn.

I have been meaning to do that to mine, but it never seems needful enough.

A heavier oil might increase the range a bit.

TECHSHOP
09-01-2007, 09:50 PM
Three random tangents to all this:

1) One place, I went to daily for the pay check and not the work, had an old 3~ (Kalamazoo?) saw that cut a$$backwards, always thought the electricians wired it up "wrong" from new, but now...

2) Today I finished my "latest and greatest cart/misc storage/no more bending/falling over" 4x6 saw stand, but...

3) While using the saw on the new stand, I actually cut :eek: the the cord of my band saw. Who would have thought THAT was even possible!

MGREEN
09-01-2007, 11:20 PM
Which way does your compound swing Mike??
snowman,
Line up the compound parallel to the ways, then swing 10 degrees
which is half of the included angle of 20 degrees.
Like this:
http://i34.photobucket.com/albums/d140/MIKEGREEN555/DSCF0732.jpg
This way you can cut on the normal side of the work.
Mike

lazlo
09-02-2007, 03:18 AM
Many have been done this way plus's are cylinders are cheap to scrounge, easy to mount, many come with hardware, all fittings are off the shelf, no having to strip or modify a piston and they look neat and not like your saw has been run over by an 18 wheeler.

Hi John,

Many folks did this mod when SurplusCenter had a double-acting cylinder for $20, but that sold out quickly, and everyone's been looking for a cheap replacement cylinder.

The cheapest I've been able to find a double-acting cylinder is around $60. This is the cheapest SurplusCenter DA cylinder that looks like it would work on the 4x6 bandsaws
( 1.5" bore x 6" stroke):

http://www.surpluscenter.com/item.asp?&catname=&qty=1&item=9-5084-A

For $70, I'd rather use the spring :)

Cheers,

Robert

John Stevenson
09-02-2007, 03:57 AM
Robert,
How about $4.00 ?

http://cgi.ebay.com/Chicago-Cylinder-Corp-D-00987-800-PSI-Air-Cylinder_W0QQitemZ250155223365

I have found that second hand cylinders never fetch much, manytime they are often scroungable for pennies.


TECHSHOP
Three random tangents to all this:

1) One place, I went to daily for the pay check and not the work, had an old 3~ (Kalamazoo?) saw that cut a$$backwards, always thought the electricians wired it up "wrong" from new, but now...

2) Today I finished my "latest and greatest cart/misc storage/no more bending/falling over" 4x6 saw stand, but...

3) While using the saw on the new stand, I actually cut :eek: the the cord of my band saw. Who would have thought THAT was even possible!

Techshop, Send it back it was obviously a bad design :D :D

.

lazlo
09-02-2007, 04:09 AM
Robert,
How about $4.00 ?

http://cgi.ebay.com/Chicago-Cylinder-Corp-D-00987-800-PSI-Air-Cylinder_W0QQitemZ250155223365


Thanks John! Unfortunately that's an air cylinder :)
I'm looking too...

John Stevenson
09-02-2007, 04:37 AM
Thanks John! Unfortunately that's an air cylinder :)
I'm looking too...

No it's a 'cylinder' what you put in it is up to you. Fill it with oil and fit a check valve between the two ports and it's a 'hydraulic' cylinder.

Read my post #35 many have done this mod, it's not new and it's not mine.
You can pipe up in plastic if you want as the pressures are very low and the one way check valves are available off the shelf and very controllable.

I have one of these valves fitted to the blow line on the CNC. I can set it for just a whisper to keep light chips clear or to a blast to clear and cool and it's about 20 turns between these settings so they are very controllable.

.

lazlo
09-02-2007, 04:41 AM
No it's a 'cylinder' what you put in it is up to you. Fill it with oil and fit a check valve between the two ports and it's a 'hydraulic' cylinder.

Normally a cylinder is rated as pneumatic or hydraulic, and most of the pneumatic cylinders aren't rated for hydraulic use.
But I guess you're saying that the pressures are so low that it doesn't matter.

They've relisted them for $7.69, but I need to decode the part number to see if the stroke length is long enough:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250135337754

John Stevenson
09-02-2007, 04:55 AM
Yes the pressure isn't anywhere near what an air cylinder can do.
Most air cylinders can handle 300 lbs / sq in as they have to be double rated working use.
You have an arm that weigh about 40# to lift, mounting ratio is at worse 10:1 so you have 400# force acting on a 1-1/2" cylinder or 1.76 Sq in so 400 / 1.76 = 227 lbs / sq in at a worst case scenario.

A 2" cylinder would be 127 lbs / sq in.

Worse case of lift is just above the horizontal, I don't have one of these saws but if someone gets a spring balance and weights the arm, then works out the mounting ratio you can get accurate figures but I assure you it's well withing the design of an air cylinder.

.

Hal
09-02-2007, 09:28 AM
Mike Green

What type of lathe do you have ?

I noticed that your carriage wrench is an eight point. Are they common ?

Nice looking lathe by the way.

Hal

MGREEN
09-02-2007, 12:24 PM
Mike Green

What type of lathe do you have ?

I noticed that your carriage wrench is an eight point. Are they common ?

Nice looking lathe by the way.

Hal
Hal,
My lathe is a South Bend 10L also known
as a heavy 10.
I pretty sure that the wrench is standard issue
with the machine.
Mike