Throttle Control Valve for GraverMax explained...

[Robert Morales]

"The GraverMax & its evolutionary offspring require a certain amount of minimal airflow through the pedal even at rest for acceptable handpiece response (having a little flow at all times avoids unexpected surges that may occur when starting from zero). Until the introduction of the Throttle Command Module, this minimal flow was always achieved by simply adjusting the throttle at the factory to a pre-set level. In other words, the bleed valve in the foot pedal was rotated to a certain point, as if the pedal had already been engaged to a slight degree."

Mitch,
This part of how your Throttle Control Valve works in relation to how the Graver-Max is designed to work has been very enlightening for me. Years ago I took my pedal apart to "CLEAN THE DISGUSTING COLLECTION OF DUST-BUNNIES OUT OF IT!" either because it was coming apart or I thought it was causing hesitation issues. I'm now recalling at that time I adjusted it so it DIDN'T leak air at rest! I don't feel that I have any surging at start but I might be missing some fine control. In my case it turned out that the built in regulator wasn't handling high tank pressures well. I added a Craftsman regulator to limit what it sees and that fixed it for me. Thanks

 

[Brian Marshall]

Just installed the TCM on an old GMax in the classroom. Also altered the foot pedal into a "progressive" configuration by doing a little surgery on it...

In two words - it works.

It does everything claimed. Turns an old GMax into a machine that, to me, matches and even in some ways outperforms the newest model.

Congrats, Mitch!



Brian Marshall
SJAS
Stockton, CA USA 95209
209-477-0550
instructor@jewelryartschool.com
http://jewelryartschool.com/

 

[mitch]

HI,

I would like to know how the TMC works with the Lindsay Classic ??

I have asked before but never got a answer??

Will it slow down the piston with short stroke and low pressure more that stock??

How would you set it?

AirAmp

Sorry about that- your question slipped thru the cracks (in my mind...)

Lindsays work on a slightly different principle from GRS machines, so a secondary/supplementary valve serves a different purpose with those (at least mine does). The Lindsay unit already has a needle valve in the system to provide a consistent minimal airflow, which allows the handpiece to idle between cuts- (gently oscillate between impacting & stopping entirely). However, this needle valve must be big enough- have the maximum flow capacity- to handle everything from virtually zero flow with a special order ultra-light piston (see: http://mrmengraving.com/about.html & http://mrmengraving.com/images/bio4.jpg ) to high pressure/volume with heavy pistons.

My Throttle Command Module for Lindsays uses a very tiny needle valve with a very fine thread screw adjustment. This allows me to not only confidently set the idle @ extremely low pressures (3-3.5 psi) & flow rates with an ultra-light piston, but also provides a usefully wide range of adjustment to the idle itself. So for micro-fine dot bulino work, the piston in the handpiece isn't even impacting, just the oscillation is sufficient, and with my TCM I can precisely control its speed/intensity. Basically, the TCM lets you turn a knob with your fingertips over a range of say, 500° of rotation, instead of pushing a pedal with your foot maybe 1-2° and holding it steady. And if you want to take a break, just shut off the main air supply and it's right where you left it when you come back.

As I understand it, stroke speed/length is primarily a function of the size/weight/length of the piston and the air pressure supplied in the Lindsay. My supplementary needle valve doesn't directly affect that, just provides a means of finely controlling the system at its lowest limits.

Does that help? Thanks for asking.

 

[mitch]

Many thanks to Arnaud & Brian (or You're welcome?). I'm glad you like it. As is probably obvious at this point, I'm still learning some of the details about how all this stuff works and would greatly appreciate your ongoing input. Like any new product, but especially tools, it's a work in progress.

 

[Peter E]

Mitch - Have you ever discussed some of your questions about Gravermax and other GRS products with JB Taylor? He is VERY helpful and literally knows the products inside and out.

 

[airamp]

Hi Mitch,

Thanks for the explanation on the TMC for the Lindsay Classic.

I do have a Classic with the foot pedal and also have a PC. (I do switch back to the Foot Pedal on occasion).

The Idle control on the new units (after 2001) have a newer needle valve and foot pedal set up that controls the idle easier.

The newer Classics have a liner in them (second chamber) that even controls the idle more.

I just received an ultra light piston from Santa and have been playing with it to get super small dots and it works great even at very low pressure.

I see from your letters Steve made these ultra light pistons way back when, but the newest ones with even more improvements to them are really slick little gems for very fine work.

Your work is super so maybe you could get to try the new ultra light piston..:thumbs up: (custom order)

The needle valve I use (idle valve) is a clippard fine thread flow valve that takes 9 turns to go from 0 to 5scfm@100psi. I have been using it for 2 years now.

This is a very controllable idle valve and with the new design of the ultra light piston really works without any issues at all for small dot stippling from what found.

Honestly the original needle idle control valve works great also.

The idle adjustment improvement from stock is minimal with the clippard (about an extra ¼ to ½ turn of idle control at low pressure).

Steve does have the fine idle valves on his site if a really need the extra fine idle control on a FP Classic.

Link:

http://www.engravingforum.com/showthread.php?t=6546

I am sure the TMC works great on the GRS engraving machines.

More control is always better and it seems the TMC has a great use and is a great help in making the GRS machines idle and users gain with the benefit of much more control of the tool.

AirAmp

 

[Kicker]

I want to add something on to my GraverMax to make it better control and i m thiking of the Throttle Command Module or Progressive Foot Control. can any1 tell me which one works better?

 

[mitch]

I want to add something on to my GraverMax to make it better control and i m thiking of the Throttle Command Module or Progressive Foot Control. can any1 tell me which one works better?

we need to start by determining what model of GraverMax you have and how old it is. they evolved over the years.

in general, i'd recommend first getting a good quality precision pressure regulator like an SMC 1010 or a Norgren 11-018. -this will minimize air pressure fluctuations and allow you set the air supply very close to what the handpiece requires. then if you want additional control, i'd go with a TCM for fine-tuning as your handpiece warms up so you're not constantly adjusting your basic supply pressure. i'm still not sure about the "Progressive Bleed Valves" or throttles- i just can't feel that microscopic bit of difference. the principle is sound, but it's such a tiny modification most people- myself included- probably won't notice any improvement.

as a final note: your air supply can't be too clean, or too dry. at a minimum, you need a 5μ (micron) filter and an oil-coalescing filter if you're not using an oil-less compressor. if you have high humidity you may need to investigate some sort of line dryer, too.

 

[Kicker]

Mitch. Thanks for your reply.
Mine is a 4 years old GraverMax classic and i use it for stone setting.

 

[silverchip]

Hey Mitch, I have an old Omega From Steve,I'm sure since they are now obsolete that it wouldn't make a hill of beans in regards to the Warranty. So do you have one that would work on it?

 

[mitch]

Hey Mitch, I have an old Omega From Steve,I'm sure since they are now obsolete that it wouldn't make a hill of beans in regards to the Warranty. So do you have one that would work on it?

i'm afraid i'm not familiar with that particular iteration of his design. tell me more about it and maybe i or someone else can advise on upgrades...

 

[silverchip]

It looks like a classic foot controlled model except that the bore is 1/2"? I've toyed with the Idea of selling it and upgrading but still like the tool enough to see what other options I can find.

 

[Kicker]

Hi Mitch.
Can you Please upload the instruction manuals of the TCM. Thanks...

 

[mitch]

hi Kicker-

it's in a Word.doc so if you send me a direct email by private message i'll send you the attachment.

 

[Kicker]

Hi Mitch.
I had sent my email address to your private message. Thanks for your time.

 

[Kicker]

any1 have the instruction manuals, please.Thanks

 

[mitch]

hi-
i got a request for that info from someone and sent it right out, but didn't realize it wasn't from you. i was expecting one PM, i answered it, and it turns out when i went back to check that someone else was interested, too. try resending a PM and hopefully it will work this time. sorry for the confusion!

 

[Kicker]

Hi Mitch.
Its not a problem and here is my email address: kicker@optusnet.com.au ... Thanks...

 

[mitch]

Hi Mitch.
Its not a problem and here is my email address: kicker@optusnet.com.au ... Thanks...

it's on its way!

 

[Paulie]

Mitch you bring up a good point and you are right on about the pedal valve bleed needing to be turned off and the secondary valve to do the minimum. which is what you express be done in your installation instructions. this is what my experience showed when I used the bias valve on the mach without the bleed air shut off it seemed to do nothing more than act as a fine adjustment. When i shut the bleed air off it performed the same as your valve did on the max. So the bias valve does do a lot on the new machines if the bleed air is shut off.

I must say though that this is what I experienced. I always suggest that people check with the manufacturer before changing something in case the change could cause some other issue that i don;t know about.

Bob Finley there in Emporia aka. Unbelievable artist craftsman a genius of sorts. who does some incredible deep relived carved and even 3d carving on his knives and such that he also makes, told me that when he cuts deep and needs to hog out area's that are deep. By deep I mean 60ths. or more. that's about 1.5mm for those in the metric world. He turns up the pressure or over pressures past the optimum pressure for running the handpiece normally. He like some of the older handpieces for this. he said he gets more power. I tried it and it works or it feel like there is more striking force. on the down stroke. but you need to put the pedal to the metal and there is a lot of air bleed of course. But the power seems much stronger. i don't know if there has ever been any measured data on the force but it does seem to work.

Hi Christian! I just read this whole thread trough because I cannot find any difference in operating my GraverMax G8 with the 'bias control' closed or open. When I re-read the GRS instruction manual there's not so much info on the 'bias' control. If I turn the bias open it just seems that I hear much more air escaping through the system, but I cannot notice any difference in operating the foot pedal. Stays the same when I increase the air pressure. Is this normal? Thanks in advance for any possible advice! Kind greetings, Paulie