Tormach Power Drawbar Surgery! Pneumatic Seal Replacement!
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- Опубліковано 22 бер 2015
- After about 5 years, the Tormach PCNC Power Drawbar developed a leak. A quick inspection revealed the inside was filthy (!) no doubt due to years of non-dry air combined with black pipe; this combination produced rusk-like flakes that made their way into the cylinder.
I was able to swap two of the seals for a quick fix, then ordered the seal replacement kit from Tormach to give it a proper fix.
It was easy to fix - easier than I expected!
You do want a few tools on hand:
12MM Hex key: amzn.to/1IjAJ8K
5MM Hex Driver: amzn.to/1CgwhH4
Retainer Ring Pliers: amzn.to/1FtmL66 OR
Harbor Freight Pliers: bit.ly/1CgwCtf
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Great vid. A few things about your knockout cylinder. The cylinder in that type of spindle draw bar style should always transfer the force through the spindle centre as this prevents the knockout load being transferred through the spindle bearings that’s why it has a collar. It should only ever float on the bolts that are there to keep it in a general position. The way it is operating at the moment as it rocks it is transmitting load onto the spindle bearings. That is not desirable. It does appear like the spindle knockout is not manufactured with this in mind though, a more commercial rated machine would have that plate as a two piece that would completely encircle the collar.
You need to fit at the very least a Filter Regulator (5 micron is a standard for machine tools) unit to anything that cycles with air. Cheap of ebay 10-20 dollars. Whilst it may not need a lubricator on some parts most pneumatic equipment does not have self-lubricating seals. What happens is the seals will stick slip causing them to lose their edges and loose sealing potential. The oil I would recommend is something very light perhaps C10. Almost anything with zinc in it should be ok but it has to be very thin. The cylinder appears like it has been anodised to prevent wear, this makes it important to lubricate the seals prior to assembly, not a lot of grease but a very thin film. This should include behind the piston seals. You should NEVER use anything that can scratch the inside of the piston groove to remove a seal. Brass on steel pistons, plastic on alloy pistons. When they leak internally you will hear a constant air leak coming from the exhaust of the control valve.
A couple of tips relating to the big C clip. Big clips that are loaded infrequently in a soft material will dig in over time, as a rule of thumb I normally give them a few taps with a punch to upset them prior to first removal. And finally a good rule of thumb with circlips is anything that is wider than 2.5mm you should only ever use forged circlip pliers anything made from sheet metal is normally a one-time deal. Not good for a video but if you are concerned about the circlip flying just put a rag over the top when removing it will make it a lot safer. This has saved me a few times.
Cheers
Hi John
The reason they have the plate (frame of the air cylinders) fit under the spindle shaft hub is so the power draw bar isn't pushing on the spindle bearings. The pressure required to squeeze the Belleville washers during a tool change is high enough that it could damage the spindle bearings over time, especially the shock of the cylinders coming on. Actually a very well thought out design.
Great video.
Cheers Bill
When you add circular areas together the equivalent diameter is D x sqrt(N). So a cylinder with 3 stages like that one is equivalent to a cylinder that is 100mm * sqrt(3), or 173.2mm. A 2 stage 100mm cylinder would be 100mm * sqrt(2) or 141.4mm. The 3 stage cylinder is capable of generating 3650lbs at 100psi.
Who doesn't like seeing the insides of expensive equipment (especially if it's not yours!)?. Thanks for putting it up John, looking forward to the Arduino project!
Thank you for the great video! I had memories flooding back from years ago when I rebuilt a High Pressure Air booster at my old job. Very similar in construction, only it was used to boost air from 850-2500 PSI up as far as 5000 psi for paintball applications.
Back then I did a lot of work on paintball equipment and preferred variations of Dow 33 and Dow 55 silicone based greases for o-rings. I used the thicker stuff on stationary or slow cyclic rate o-rings. Smart Parts Sleek lube.
Having seen now how that works, I am highly inclined to figure out how to fit one on my mini-mill. Building it should be pretty straight forward.
Can't wait to see what you've got cooked up with this arduino CNC gun project!
To lube air cylinders, I recommend Super Lube Synthetic Grease. It's a silicone grease with teflon. Safe for o-rings and works really well in an application like this. Not very expensive, try Amazon.
John, as you have already completed the maintenance, this might not help! Next time you have to compress an e-clip, thread a piece of .032 safety wire through the holes in the clip, then just twist the ends to pull the ring in. This has the benefit of keeping the spring clip under tension AND you can lose the harbor freight pliers!!! Thanks for the awesome videos!
Just a thought on your Drawbar issue. I had some what the same issue with trash in my air. I got what I call a toilet paper filter. I got mine at a local auto parts. I just looked on amozon and it's listed as "Motor Guard M-30 1/4 NPT Submicronic Compressed Air Filter" they sell a replaceable filter for it but a roll of toilet paper with the core removed works perfect for removeing particulates from the air before it reaches a tool and also a secondary moisture filter, assuming there is one. No grit no problems. I have really enjoyed your videos, keep up the good work.
John, the cylinder shaft seal is only ever used on the bottom cylinder because that is the only one with pressure on the return side of the piston. This is also probably why you have the most crud in that section, because there is constant feed air to the cylinder. It may be possible to rework the return so that it only uses pulsed air, with a timed solenoid valve. It would only apply air long enough to retract the cylinder, then turn off. This would probably reduce crud buildup and not put pressure on the seals all the time. Although that would also require the seals to hold the weight of the pistons, through drag. I would apply white lithium grease to all of the seals when assembling the cylinders because there is no oiler to ensure they are lubricated. You probably should look at adding another inline filter to the machine and getting one of those cheap HF air dryers (21CFM for $400).
Hello John. Thank you for this excellent video as I'm having the same issue. Regarding the snap ring pliers, I struggled with low quality harbor freight pliers too. After a lot of research, I bought the Craftsmen 47411 (small) and 47412 (large) pliers. They are spectacular tools and they make taking out snap rings easy.
Awesome video. I love teardown videos of things like this. Gives me the info I need for the future if I get one.
Thanks again!
Good job explaining
I bought our first new mower in 2012. I had warranted problems from month #1. I learned the importance of the dealership from this. Low price and 0% financing shouldn't be the only factors in a business purchase. Next time I'm going to Deere, and honestly I should have known better.
Amazing you got 5 years out of it.
NYC CNC Apples and oranges. I own a lawn service, you own a machine shop but the lessons from buying equipment are the same. John Deere= higher priced equipment but way better dealership. Warranty is only as good as the dealership dong the work; that's what I learned. Our new Toro(in 2012) broke down from month 1 and the dealership sucked. Flat out stupid mechanic at Toro. I will not allow them to work on my machine so I have to drive 55 miles to get warranty work done by a reputable dealer.
Thanks for the video, John! I'll be happy to have this to look to when rebuilding my setup.
Tormach recommends lubed air for the pneumatic cylinder. Don't buy it from tormach. IIRC they ask about $90. The one they sent me was a carbon copy of the filter/lube setup they sell at harbor freight and ebay for $35-40. I know they need to make money off every sale, but in this case they're asking a bit much.
I jumped in my seat when the C clip sprung out. Gets me every time.
Pro tip: Use a slot screwdriver with your other hand to lift the back of the C clip out of the hole.
nice job.
A trick for removing external o-rings. Grab the o-ring at the 3 and 9 position. Squeeze your fingers together, while letting it slide up the cylinder (towards 12 o-clock.) It should create a loop that you can get your scribe or pliers into and roll it off. It might not work with that stiff seal, but should work great on the o-rings.
Also, in the Tormach Power Drawbar manual it says the following:
Before You Begin
Air Requirements
Make sure your setup meets the following air requirements:
• Air Supply. The Power Drawbar requires an operating range between 90 psi and 120 psi. If supply exceeds 120 psi, a regulator must be used.
• Dry Air. We recommend you use a filter, desiccator, or compressed air dryer between the compressor and Power Drawbar to make sure the air is dry.
• Lubricated Air. Air should be lubricated with common air tool oil. Use the FRL Filter-RegulatorLubricator(PN 32457) or similar for this purpose. Refer to the documentation that ships with the
FRL for more information on installation and use.
Love you videos and more so your honesty John. just a though, one thing that could have helped is some lubricant during assembly. as with most components that require lubricant, the most crucial time is start up strait after assembly. thanks again.
Good video but I would always apply a little lubricant to the seals before insertion (either proper oil seal lube or Vasoline will often be fine. Install a high quality air filter dryer in your air line and drain the compressor weekly! See Tormach about the need for air line lubrication for this equipment and make sure you have some spare fittings and pipework as they will soon leak and / or crack taking them apart like that.
Buy a set of proper quality circlip pliers of the right size and method of operation (the 3 handled ones can work well to open or close circlips under pressure but I prefer separate tools). Use a tooth brush and solvent or water based cleaner to clean grooves.
I don't know if it is appropriate for your shop but a pneumatic vice type gripper / stand on a work bench which is operated by a foot valve to clamp / release can save a lot of time and leave your hands free to hold awkward items - however not advisable if you have youngsters or careless people about!!
Good vid John. RE: Removing large internal cir-clip: I have had best success having a pocket magnet to lift up one side whilst slowing raising with your cir-clip pliers. The other catch is to squeeze the pliers together evenly (scissor like) rather than having the clip pressing against the part and only one plier tip retracting the spring (shows up well in your vid). They are generally a PITA sometimes. Lube on seals for install and I think Isopropyl alcohol is a better bet than acetone. Acetone is possibly detrimental to the o-ring seals join - adhesive. Having said that you only wiped it lightly not bathed the seal itself so prob no big deal.
On a side note I would be interested to hear your thoughts on how you committed to purchase your machine tools and what pay back ROI period you based your financials on.
Have a great day.
I'm currently building a power draw bar for my mill that I'm CNCing. I ordered the steel for the frame on Friday. The power comes from two brand new 80mm SMC air cylinders. SMC recommends no lubrication for the feed air, but I do plan on using very clean air. If your cylinders aren't SMC, they're SMC clones. There is a Chinese company that sells clones of popular SMC parts on eBay. I bought a solenoid valve and a filter-regulator unit, both SMC, used on eBay as well. The clean air from my oil-less compressor will be routed through the filter-regulator and then through the solenoid valve. All exhaust ports in the system will have sintered brass mufflers to keep out any crud. From what I've seen of SMC quality in the nastiest and most abusive industrial applications, my nearly clean room application should outlast me before any maintenance is needed... I hope.
I noticed your air cylinder rocks to the left under pressure. This can be problematic for air cylinders. The SMC data sheet for the air cylinders that I'm using specify the maximum lateral forces on the end of the shaft. The bottom shaft seal would be my expected failure point if lateral forces were the cause. It's a bigger problem for long stroke air cylinders, but I made sure to design my power draw bar so the shafts only push vertically. I have a steel pusher plate between the end of the shaft and the top of the draw bar, and the shaft is not attached to the pusher plate so there can be almost no lateral force on the shaft.
Even though SMC recommends no oil in the feed air, I wondered if the cylinder manufacturer packed some sealing grease in the air cylinder when new, and if the rebuild kits would come with new grease. Apparently yours didn't, but if just doesn't seem right to me that the seals would be wiping against acetone cleaned dry surfaces, but certainly the rebuild kit instructions would tell you if any type of lube should be used.
27:50 - I'd put sintered brass mufflers in the two exhaust ports on the cylinders. Nothing should make it in there, and the exhausting air should keep it cleaned out, but I like the system to be sealed to keep out contaminates. Also... mud daubers! :-)
I'm a bit concerned. The three stack air cylinder used on the Tormach should be able to exert 3300 pounds of force at 90 PSI. I thought 1000 lbf would be sufficient in this application (not sure where I heard or read that), so I designed my power draw bar to exert 1400 lbf at 90 PSI, thinking that I'd run it at 60 PSI or so. My old spindle motor is only 2 HP, and the replacement I'll be using is only 1,5 HP, so maybe I'll have enough draw bar tension. I guess I need to look into the draw bar tension force some more, which is bad as I already bought the air cylinders. :-/
NYC CNC I've been using the Chinese eER20 collet holders on eBay and pseudo-TTS for at least a couple of years, with manual tool changes. The benefits are much greater with CNC and a power draw bar. Ultimately, I'd like to have a pick-and-place tool rack on the side of the table in lieu of an automated tool changer.Here's a similar class of machine to my Grizzly G1006 mill/drill, using about the same (or slightly less?) draw bar tension that I'm planning on using, so I'm still hoping for success.www.littlemachineshop.com/Instructions/2936PowerDrawbar.pdfIf I need 2500+ pounds of force, I'm going to need a new plan, because I doubt the cast head of my mill/drill could withstand those forces for very long, even with the substantial reinforcements I'm making.Steel for my powered draw bar will be here tomorrow. The incidental items from McMaster are arriving today. The 2 HP VFD arrived this morning. I just ordered a heavy PVC tarp to use as a slightly upscale version of the floor-to-ceiling shower curtain enclosure system employed by home shop machinists on a budget. I stole the Tormach sliding front door design but haven't bought the black pipe or 2' X 4' clear polycarbonate hanging panels yet. I'll start posting short videos soon, with each devoted to one step in the CNC conversion process. Search UA-cam for CNC Turd Polishing and you should find them. :-)
John, I have been watching your stuff for some time now and have found your channel very inspiring. I bought a Taig not to long ago so in a way I'm kind of following in your foot steps. All of that aside, I am a mechanical engineer and work in the fluid power industry, most specifically pneumatics, and work for a company that is an SMC distributor. With the correct air preparation that cylinder should last a lot longer than "many thousands" of cycles. Additionally, you should not have to lubricate, the industry almost never lubricates anymore. I could make some recommendations for air prep if you would like that could do wonders for you.
Make sure your oiler on the back of the machine in the regulator setup has the dial set to max. The oil flow can be adjusted and it is very conservative displacing oil at lower settings. Air tool oil is recommended !
Yes, oiling up the O-rings everywhere is important! You can even get special grease just for rings to make sure they do not dry out and start cracking.
Since the two piston exhaust ports you mentioned at 37:40 are exposed to atmosphere contaminated with dust, do you think it may be a good idea to filter the ports with an oiled cloth ball or maybe an oiled piece of Scotch Brite? It would reduce dust getting into the working cylinders, scratching walls and contaminating seals.
John, thanks for letting us watch the maintenance. Interesting design. As far as pressure goes, keep in mind that a 4" cylinder has a bit over 12 square inches of surface. At 100 psi, that's 1200 lbs of force. Three of those stacked and you get over 3600 lbs on the drawbar.
As for the Harbor Fright circlip pliers, there's nothing as expensive as a cheap tool. (Cheap meaning low quality...if you can pick up good quality for little money, like used at a flea market, go for it!). Poor quality tools cost you every time you use them...they aren't fun, they can damage things, cost you time, and even injure you. Eventually you replace them with better, so why not just get good stuff to start with? More up front but cheaper in the long run.
I have two air nailers...one wants airtool oil, the other does not. Read the directions! To deal with this I got an inline oiler and attached it to a 1' section of air line with quick disconnects at each end. When using the oil loving tool I connect it to the tool and the air to it, and when using the other tool I just use the air line alone. That way I don't get oil into my air line (very bad when using it for painting...or with the oil hating tool). I prefer the nailer that doesn't use oil...because it doesn't exhaust oil on or around my nice wood projects.
-- Mike
NYC CNC
Thanks! I got 1200 from the area of the piston top (Pi x R^2....I didn't have a calculator or paper handy, so I just used 3 for Pi...the actual answer is closer to 12.566, not 12, and you said the diameter was 4", so R is 2) and the air pressure of 100 psi. 12 square inches times 100 pounds per square inch = 1200 pounds of force on the top of the piston (and on the sides, top, etc. too of course, but only the piston can move (we hope!). You have three pistons, so three times the area, and three times the total force = 3600 lbs.
It's that sort of area multiplication that makes vacuum tables work...it doesn't take very many square inches at 15 psi (1 atmosphere more or less) to give a fair amount of holding force. For instance, a 10" x 12" plate with a vacuum under it and room air on top is held down with 1800 lbs of force (10 x 12 x 15).
-- Mike
BigMjolnir little clarification, force on side of cylinder is not 1200 pounds of force but is equal of circumference times stroke of cylinder (circumference=2xPixR, R is the radius of the circle, Pi approximately 3.142) and force on bottom of cylinder smaller then force on top by area of rod times pressure (useful area on button is smaller), but design they use it apply pressure to only one cylinder for retracting so retracting force is more than 3 times smaller.
For large O-rings that don't move very fast (so this would not work with a nail gun) I would recommend Dow Corning's High Vacuum Grease for all sealing surfaces. This is super thick stuff and will stay where you put it for many years. This would have also made it a lot easier to assemble everything at the end of the video.
When you need to be delicate, yet have a tool that is strong enough for such small spaces dental tools are great. So long as they are steel and not the cheap plastic handled tools.They also come in a variety of angles, shapes, and hooks perfect for pulling rubber O-rings out.
I've never seen one of those multi-stage cylinders disassembled, thanks for that. Ideas for Arduino/pneumatic based application; small sheet metal guillotine? Maybe with electronic backstop? Tube bender with electronic angle setting?
Hi John, I have a suggestion. Could the dirt and crap also get in from those exhaust ports during normal operation? Back in the day, we used to use pneumatic silencers on our cylinders in the exhaust port that also had a small particle filter in them. Food for thought. Cheers, Aaron.
When I worked with the fadal 4020 I sometimes (actually many times) got to see the spindle head torn apart. The draw bar is actually pretty cool stuff. As is all related to these machines.
The fadal or the drawbar? Ok machine and drawbar was a bar with them belleville springs. But to understand how the parts work together to take tools, that is just something. For operator that is just M6 but there is more to that...
Those retaining clips are called "Cir Clips" short for circular clips
Super Lube Synthetic Grease is good for applications like this. Its a silicone grease with teflon in it. Not very expensive, you can get it at some hardware stores or Amazon.
Good vid, but you should always assemble pneumatic cylinder seals with grease. I have to do repair works quite often in my work and my personal favorite is Klüber Paraliq GTE (food grade stuff, but still my favorite). Don't know if it's available in states? But you also never shouldn't use regular oils in cylinder assemblies. Some say oil mist devices are needed, but that's not true at all. There's tons of applications that can run dry, but even then, Grease those seals before assembly, actually I haven't seen a repair kit that wouldn't have small grease bag with them. Hint for those big circlips, I like to use two small screwdrivers to align circlip out. For removing seals I like the common O-ring tools. They're sharp and kit will always have and appropriate shape to push in rubber and remove old seal, note push in seal and pull out, don't push between frame and rubber to avoid scratches.
Bottom piston is dirtiest, because it's the only one getting air for the retract function; and, to a lesser extent, because all of the moisture is going to tend to travel down the line and settle at the bottom of the stack.
Question, though, do you know about what the stroke length of these pistons are?
Nice video, all your videos are appreciated I am a big fan of sharpie notes when dis assembling and reassembling parts here's another tip I like to put the date and the part numbers right there as well that way the next time it comes apart I know how long it's been since the last time the job was done and of course the part number should be written where it's easy to find. I would also lube the o rings mineral oil or silicone based lube. I have even heard of using a little water and dish soap but only for assembly of non moving parts I'm sure others will chime in on the proper lube as well. Thanks and keep up the good work
NYC CNC The sharpie should hold up quite well I have only been able to remove it using Lacquer thinner, "my favorite solvent" for cleaning metal parts including the nasty oily coating on p&o sheet steel. I'm also a big fan of the "JUSTRITE 10208 Plunger Can" to efficiently dispense solvents onto shop towels Other favorite items to mark with dates include newly exchanged welding / shielding gas cylinders, newly replaced spools of solid core mig wire, Motor guard air intake filter for the plasma machine (all filters for that matter) and new tools. It's always nice to know at a glance the last time a filter was changed or just how old your tools are getting etc.
I think the bottom is the worst because of gravity no? Water settles in the bottom? Cool vid.
Next time use silicone spray or silicone grease... even just a small amount will keep your o-rings VERY happy !!! ...and the assembly much more fun/easy !!!
Also, you don't have to remove the screw on the left to take off the air cylinder. Rotate the little arm on the right out of the way, and you can twist the cylinder enough to clear the ring on the PDB.
NYC CNC On mine, the whole unit pivots on the bolt on the left side. No need to loosen anything. Maybe the design has changed over the years.
At around the 4 minute mark when you activated the cylinder: Is it supposed to rock like that? Looks like there's an adjustment screw to limit the "rocking" of it. Seems like that may be another wear item but it's not too clear to me. Cheers
Gravity is why it is the dirtiest. Get an oilier and moister control on your air.
Busting chops.
Great vids.
John,
How come the power draw bar is not secured on both sides? Seems like a lot of possible wear pressing the draw bar at an angle, as slight as it is.
collar on the spindle, like he said. I know, I know, 3 year old comment ;)
Is that power drawbar unit supposed to be loose like that?
When you tested the lock/ unlock function you could see the entire bottom right side of that unit pick up and then go back down. It looks incredibly loose........
you should have put some silicone grease when assembling those o-rings since you're not oiling it or at least coat the parts with some air tool oil - those should not run dry.
I think you need an air-dryer to get rid of the crud, most likely created by the water vapors/condensation in the air source,the bottom one got more since it always get air and was also leaking.I noticed it goes crooked when you activate it, seems to be holding on to the cam bolt and only after some motion is leveraging on the collar but only on 1 side (the right side the way you look at it), I think the cam should be longer a bit (maybe space it with a washer or 2 on the bottom) so it touches on both sides of the slot on that shoulder.EDIT: not sure if you need to use an oiler, it might fill up your bottom cylinder after a while, i don't think you need one since like you said is not a continuous motion but i would think every once in a while just put a drop of airtool oil in thtu ports (both in/out ports) with a syringe,
Got that same double sided ratchet. Love that little guy. My guess is the bottom is dirtiest because the water pools there.
NYC CNC Same here. Some Bronze Muffler/Filters should help keep a little bit of rubbish out of those 2 exhaust ports. BTW, more hints of the next project would be awesome :) Green is good :)
NYC CNC I got it :) Well, at least I think I do :)
A tip for next time, Use a tooth brush, and parts cleaning fluid. That will remove ll the gunk without having to worry about damaging the seal surfaces.
Hazard Fright strikes again!!!!
I am pretty sure Hoss @ hossmachine has plans that he sells for a multi-stage air cyliner. I couldn't find them on his site after a cursory look, but I think they are there. He mentions something about the build in this thread: www.cnczone.com/forums/benchtop-machines/171662-power-draw-bar-idea-feasible.html
Also, I am pretty sure a 3 stage 4" cylinder would have the equivalent force of approximately a 7" single stage cylinder, all things being equal. The precise radius should be the square root of 3 * (r^2) or in this case the square root of 12. Which is ~3.464".
I enjoy your videos, particularly your Arduino based ones. IMO there is a shortage of Arduino, or any micro controller based videos, that are accessible to people who aren't programmers by trade. Particularly ones with practical applications. I would love for someone to prove me wrong.
Aaron, you are everywhere... ;-)
NYC CNC Sorry John,
I was commenting on seeing my mate Aaron Powter pop up in the comments list. Not trying to confuse you... ;-)
Question for those who know should you lube the seals with something before installing? I worked with a guy who would always grease them and never really knew if it was a good idea.
David Queen Yes, use Parker o-ring lube or Sil-Glyde, avoid petroleum based lubes.
remy5405
It is all about materials compatibility for the intended application.
Most o-rings and seals for automotive use are not natural rubber, but instead are completely synthetic or synthetic blends such as Buna-N that is a natural rubber and Nitrile blend.
It is well known and established fact that most petroleum based products attack and deteriorate natural rubber and some synthetics.
There are 8 of the 18 most popular materials used for o-rings and seals that are positively contraindicated for use with petroleum based products and are listed as such in most material compatibility references.
Trelleborg, Parker, NOK, Dow, DuPont and practically every manufacturer of o-rings and seals globally will advise against using natural rubber and certain synthetics to seal petroleum products due to material deterioration and reduced service life.
The Parker application and installation manual clearly states that using petroleum based lube for assembly and operation is only acceptable on PTFE (Teflon), EPDM (Ethylene Propylene), CR (Neoprene) and MQ/VMQ/PVMQ (Silicone) o-rings and seals.
That does not include buna, natural rubber and approximately 40 other o-ring and seal materials.
Here is a quote from the Parker manual "Parker Super-O-Lube is a silicone fluid recommended for use with all rubber materials, o-rings and seals. Only a thin film of Super-O-Lube should be used with silicone rubber to prevent seal damage."
Dow Molykote 111 Silicone O-Ring Lubricant is specifically formulated to lube o-rings and seals, prevent degradation, is silicone based and contains no petroleum products.
The takeaway is that if you cannot positively identify the o-ring and or seal material, be safe and use a silicone based lubricant and avoid the possibility of petroleum based lubricant damage... unless you are a gambler and or do not object to repeatedly performing the same repair sooner than necessary.
I agree with your statement about brake fluid damaging most materials including paint finishes, and petroleum products damaging brake system components.
I have witnessed the results too many times.
Good thing here, is that John's PDB does not employ brakes or brake fluid.
Hi John good video I work for Festo an they are located in New York they are building a new mfg. facility in Mason Ohio.So this will be my last year with them but they make a lot of pneumatic actuators among other things check them out they have flying seagull, kangaroo,water jelly air jelly and just some really hi tech stuff.any way keep up the good videos,
They are called "Snap rings"
The tips of your c-ring plyer are turned wrong
bottom one dirtiest, shit rolls down hill? I like just a touch of lube on my o rings. Even if barely a drop. Helps make assembly easier and sometimes can even save an o ring from damage.
I usually put clean oil in the groove i think it helps the seal as well as rubber.. I think..
U forgot new orings on first stage u did
A good source of pick like tools is your dentist. I asked her she any old tools she doesn't use and she gave me a couple dozen.
There should probably be filter plugs on the open ports of the top two cylinders.
www.mcmaster.com/#filter-plugs/=wfo8rz
Maybe the bottom one is the worst becouse gravity will take the moisture and crud down?
NYC CNC I think it's forced out when forced closed on the PDB close cycle.
NYC CNC I agree with you John. Maybe the air that goes into the bottom stage to release is more the issue and the fact that the ram extends into open air here and it is closer to the belt drive dust etc to retract it back into the cylinder. Like suspension - the last seal on the ram near atmosphere always dies first. Maybe a simple neoprene or rubber below/boot there would help?? PS: are you tired of everyone's expert 'tips' yet ;-)
I love using a swipe of silicone ring lubricant. It is not terribly cheap for the good stuff, but I use it on all of my rebuilds (unless it is an oil exposed ring). It works well, and makes things last a very long time. For example, on an air filer, it used to get gummed up with my less than clean shop air, but after installing a 2 stage filter, and regreasing, no issues. It really extends the time between servicing.
I am a bit disappointed with Tormach though... They really should put a breather on those bottom ports for the top two pieces. It prevents crap from getting in and damaging the seals. Simple vent filters. www.mcmaster.com/#breather-vents/=wjeznv
Yep, a little dab on silicone lube when you install an o-ring goes a long way to preserving the life of the seal - never go in dry! ;)
Jon Massey oh dear. That's one way to put it.
Use a pencil to remove seals from grooves. The pick will scratch and that tiny scratch will cut the new seal. PITA. An old dishwasher is great to have for wahing parts before assembly. Ours uses 3 gallons to wash and 3 to rinse and it has an element to heat the water as it washes. Fill it from a bucket. Don't use your ma's. Will be the end of you!
NYC CNC My friends make fun of me but it was by far a great use of the floorspace. Don't use the jet dry stuff ;]
Parker makes a reasonably priced set of brass and stainless o-ring tools, but sharpened chop sticks work exceptionally well removing o-rings/seals without damaging the seal or the groove and they are free with takeout.
An good alternative are glass filled polymer soldering aid sticks.
I use an old used Kitchenaid dishwasher in the shop to clean small items. It does an exceptionally good job using the typical Cascade dishwashing detergent, best $45 tool in the shop.