Small Mods To My Hf 4x6 Bandsaw

Nice job, I also would like to see the info on the hydraulic downfeed. Sounds interesting.
 
Here's the part numbers for the air cylinder and flow control valve purchased from Zorro industrial online. They had they best prices I could find:

Air Cylinder, 10.6 In. L, Stainless Steel $19.94 /ea

by PARKER

Technical Specifications
Zoro #: G6085037 | Mfr #: 1.06DXPSR06.0

Cushion Type: None

Cylinder Type: Round Non-Repairable

Nose Mount Thread: 5/8"-18

Finish: Silver

Dimension A: 1/2"

Dimension Cc: 0.312"

Piston Material: Aluminum

Piston Rod Material: Stainless Steel

Rod Dia.: 0.312"

Single Acting/Double Acting: Double Acting

Magnetic Piston: No

Tube Material: Stainless Steel

Max. Pressure: 250 psi

Dimension D: 1/4"

Dimension Kk: 5/16"-24

End Cap Material: Aluminum

Rod Thread Length: 1/2"

Green Certification or Other Recognition: RoHS Compliant

Body Material: Stainless Steel

Item: Air Cylinder

Dimension B: 0.624"

Rod Thread Size: 5/16"-24 UNF

Bore Dia.: 1-1/16"

Pivot Hole Dia.: 0.251"

Dimension L: 0.34"

Dimension E: 0.38"

Stroke: 6"

Overall Length: 10.6"

Mount: Nose and Pivot

Temp. Range: -10 Degrees to 165 Degrees F

Features: Not Switch Ready

Zoro Number: G6085037


Air Cylinder, Double Acting, Round Non-Repairable, Bore Dia. 1-1/16 In., 6 In. Stroke, Nose and Pivot Mount, 250 psi Max. Pressure, Cushion Type None, -10 Degrees to 165 Degrees F Temp. Range, 10.6 In. Overall Length, Aluminum Piston Material, Stainless Steel Body Material, Silver Finish, Aluminum End Cap Material, Stainless Steel Piston Rod Material, Magnetic Piston No, Tube Material Stainless Steel, Nose Mount Thread 5/8 In.-18, 0.312 In. Rod Dia., 5/16 In.-24 UNF Rod Thread Size


Valve, Flow Control $18.93 /ea

Zoro #: G3077627 | Mfr #: PF 400B

Max. Temp.: 140 Degrees F

Adjustment Knob: Knurled

Max. Operating PSI: 2000

Body: Brass

Item: Flow Control Valve

Outlet Port: 1/4" NPT

Inlet Port: 1/4" NPT

Coefficient of Volume: 0.8

Zoro Number: G3077627

Mfr Number: PF 400B


Air Flow Control Valve, Female Port Size 1/4 Inch, Maximum Operating Pressure 2000 PSI, Cv 0.8, Brass Body, 140 Degrees Fahrenheit

Parker lists the valve as a hydraulic control valve, Zorro has it listed as an air control valve.


The cylinder uses 1/8" npt port threads. The valve is 1/4" npt. They also have an 1/8" npt version at Zorro for the same price.

I used two grease gun hoses from Ace hardware.
Lubrimatic 3000 PSI 12 "
1/8 " NPT Each...

Quick View
$7.49

The accordion dust boot is: Neoprene Multi-Convoluted Rubber Bellow 130mm x 35mm Connector 7mm (BT-1126) purchased from the rubberstore.com a bit pricey at $15.99

Everything else is either brass fittings or fabricated.

The clevis rod end is made from 1"x 1" 6061-T65 square stock. It is 2.25" long. I milled a slot 1.5" long with a 1/2" end mill. I don't like using 5/16 x 24 threads in aluminum, so I drilled and threaded the clevis for 1/2" - 13 and made a bushing from 4130 and drilled and tapped it 5/16 - 24 inside and 1/2" - 13 outside. I used red thread lock to secure it in the aluminum. I reamed the saw pivot arm pin hole to 3/8" and drilled and reamed a 3/8" bore through the clevis. I turned a 3/8" clevis pin from 4130 and cut a lock ring groove in the end. The clevis and a locknut were threaded on to the piston rod and installed onto the pivot arm.

I then extended the cylinder to about 1/2" from the end of travel and marked the mounting hole for the cylinder pivot rod, making sure that when the saw is moved to the vertical position the cylinder has clearance so it can not hit the bottom of the stationary vise jaw. The cylinder has a 6" stroke but only part of that is used. It never hits either end of its travel. One aspect to note is that the sides of the machine bed are angled with respect to the vise surface so any pins or brackets that are mounted to it need to be level with the vise surface.

The pin that secures the cylinder to the bed is turned from 4130 3/8" rod. It is 2.5" long,threaded on the base end to 6mm with a 5/8" long shoulder area at 3/8" diameter and the outboard end is turned to .250 and threaded 1/4-20. I reamed the pivot bore of the cylinder to 5/16" and turned a delrin bushing to 5/16" outside with a .250 bore. This is pressed into the cylinder and makes for a smooth and wear free bushing. Steel on aluminum tends to gall and wear quickly. I drilled and countersunk the pivot pin hole in the saw bed and threaded it 6mm. The pin needs to be parallel with the vise base. I installed the pin and used a locknut on the inside of the base. Next I bent a 4" long piece of 1" x 1/8" hr flat bar, the base end is 1 3/8" to the bend and the pin end is 1 1/8" to the bend. This needs to done to fit. I drilled and reamed the pin end for a very tight fit. The bracket needs to be twisted to compensate for the angle of saw base sides. Then I cut two pieces of 1/4" x 1/8" hr flat bar and welded them to the top and bottom of the bracket. A little time with a grinder rounded the pin end to clear the cylinder.2 holes are drilled to mount the bracket to the base, I drilled and taped the base for 4mm socket head screws. I used 1/4" - 20 nuts to hold the pin end securely. I don't think the bracket is absolutely needed, but it adds a lot of strength and gives a rock solid feel when the saw is lifted and resting on the hydraulics.

I used a union on one of the hoses, and just direct threaded the other ends into the brass fittings. I made a simple bracket to hold the valve and some sheet metal to make a cover. A 1/4" pipe plug serves as a fill port plug. The valve has a one way check valve built in and the needle valve for control. When you pull up on the saw the fluid opens the check valve and allows full flow. When you let go the check valve closes and the needle valve allows fine control of the downfeed. I would use the yellow colored gasline teflon tape to seal all the fittings or a good quality thread sealant.

When first filled the systems jerks and groans like the Titanic going down and breaking apart. That is air in the system. Since this is a horizontal system with no reservoir it is difficult to remove air from the system. I used a mityvac brake bleeder - the hand operated pump type to pull a vacuum on the cylinder. With the bleeder cup half filled with hydraulic jack oil(mineral oil based available at auto parts stores and Ace hardware) I pulled 24 inche HG and then relased to mityvac vacuum valve. It pulled most of the oil in. I did this until no more air bubbles were in the clear tube to the fill port. About 4 times and immediately put the fill plug in tight. There was no more noise and the saw was controllable to the finest degree with no jerking at all. I installed the pricey little dust boot to keep all dirt/chips off the rod and to make sure when I put a vacuum on the system it wouldn't suck in air at the rod seal. So far it has worked great. With the valve closed I lift the saw and it holds so I can set the material in and set it to length and just turn on the saw and just turn the control knob to get the desired feed. Just like the industrial saw I used when I worked for a living.

This is just how I made my system and I am not suggesting anyone else do it the same. The people who are reading this post are very crafty and knowledgeable and will find better ways to do this. I would have used a vertical cylinder but didn't want to deal with making bell cranks and large brackets. The old spring system can go back on in minutes if the hydraulics fail. This was a fun project. All dimension I gave are for my machine. Your machine may vary a lot.

I'll take more photos and post them today. If I have been too long winded or not supplied enough detail let me know. I don't have blue prints, I just fabricated as I went along.

Roy


Took some more detail photo's:

Clevis, cylinder mount bracket and pin, control valve and mount and mityvac brake bleeder .






DSC_0326.JPG DSC_0327.JPG DSC_0328.JPG DSC_0329.JPG DSC_0330.JPG DSC_0331.JPG
 
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Thanks for the info, Roy. Again, nice job!
 
Roy, That cylinder system works just fine. I did the same thing to mine and it controls the feed so much better and I get much straighter cut with it.
 
Roy, That cylinder system works just fine. I did the same thing to mine and it controls the feed so much better and I get much straighter cut with it.
Yes I agree with you. It is very smooth and lets you adjust cutting pressure down to a gnats behind. It takes a lot of perseverance and patients to adjust the saw for straight cut, and I think the downfeed just enhances the cut. It is also a pain in the keester to lift the saw and lock and then lift the saw to unlock. This way you just leave the valve closed and lift the saw where you want it and let go. It stays put. Much easier on the shoulder for me.
 
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Easier on us is the key, If it helps keep some of us being able to do things, That is what it is all about. By the way what branch, I'm retired AF.
 
Easier on us is the key, If it helps keep some of us being able to do things, That is what it is all about. By the way what branch, I'm retired AF.
You are sure correct on that. Army 68-71, Berlin 69-70, RVN 70-71 Track vehicle mechanic.

KVT Thanx for your service to the country. We need more like you.
 
Thanks for the extra information on the hydraulic down-feed, Roy! A person couldn't ask for a better explanation or clearer pictures.

I've looked at several variations of the hydraulic downfeed mod for this saw and this one is extremely clean and very well thought out. I like how everything is attached to the cast iron base for maximum rigidity and yet all the saw features are retained.

Very nice job.
 
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Would filling the cyl with hydraulic oil before install help to eliminate some of the air bubble problems.
 
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