[ImagineRobots]

Another floating power draw bar design for my X3 mill. I only had to machine a base plate and spacer. Everything else was bought from McMaster or Ebay.

I bought the new draw bar and Bellville washers directly from Tormach. It is the same parts that they sell in their complete kit! Fits nicely on the X3. I am also using their TTS system.

Foot switch, 5 port valve, and 4" Fabco cylinder bought from Ebay.

Last picture shows the orginal drawbar from the X3. The cap came off!!! The cap is actually held on with a pin and it sheared off. The Tormach drawbar appears to be one piece so no worries about the head coming off.

Here's the vid again:

[ame=http://www.youtube.com/watch?v=tbUNKx5wrmw&list=UUPw_8uMdPFrSkW8e4MuBlZQ& index=1&feature=plcp]Movie_0004.wmv - YouTube[/ame]

[cornbinder23]

Nice! great to have the PDB dont know how I lived without it for so long!!
One question though, why is the air bypassing on the downstroke?
You will generate more force and it might actuate a little faster if the air actually goes into and stays IN the air cylinder:stickpoke.

JTCUSTOMS

[ImagineRobots]

Nice! great to have the PDB dont know how I lived without it for so long!!
One question though, why is the air bypassing on the downstroke?
You will generate more force and it might actuate a little faster if the air actually goes into and stays IN the air cylinder:stickpoke.

JTCUSTOMS

It's not the prettiest thing but it works. Focus was on not having to machine too many custom parts for the drawbar.

I have a muffler/valve on each exhaust output that I can use to control the speed of the downstroke and upstroke (you can see them attached to the solenoid) The air noise you are hearing on the downstroke is from the exhaust that is set very restricted and the air is still flowing into the cylinder. I was just being extra careful since this was the first run and I didn't want the downstroke crashing down on my drawbar head too quickly. I could definitely tune the exhausts later to speed things up.

This drawbar is so cool. For some reason I'm mesmerized by this stuff and can keep watching it or cycling it forever on video or real life.

Next step is to add a counter weight for the Z axis. Then I'll do the pulley swap mod that PriddyShiddy did to speed up the spindle. 2000rpm is way too slow for a bed that can do 100 to 200 IPM. Scared to swap the spindle with higher speed bearings so I'll just see how hot things get. Then I need to get the Fog Buster (which means I need to buy a compressor too) Almost there .....

[robcap]

Nice job.
How long is the Tormach drawbar? I'm wondering if it will work with my G0704.

Rob

[ImagineRobots]

Nice job.
How long is the Tormach drawbar? I'm wondering if it will work with my G0704.

Rob

Tormach Power Drawbar is 11 7/8" from shoulder to thread end

Power Drawbar Part# 31320 @ $38.50 ea
Belleville Washer Part# 31319 @ $2.50 ea

[WOTDesigns]

very nice! what was the total cost? I'm having a hard time convincing myself to make one since it will put my tormach purchase further away.

on the bearings and heat I generally run the spindle around 3500-4000 rpm and the bearings get pretty hot after an hour or two but not terrible. I think the best thing to do is to buy a new spindle and quill from LMS for around $225 rather than try and fight the old bearings off. I'm ordering a G0602 later this month which is what I've been putting off the bearings for. with a lathe I'll be able to polish the spindle to get a good fit on the bearings.

I'll try it and if it works out (and you dont have a lathe) you can order the spindle and have it shipped to me to polish and I'll mail it to you, just pay shipping.

Honestly I've been shocked at the number of hours I have on my x3 with virtually no issues. I'm doing short run manufacturing and job shop, literally hundreds of parts, and not one beak down other than fuses and my quill mount for my light causing spindle to seize.

on the counterweight if I were to do it again I would go with a flat plate that weights could be added or removed from by installing pegs/dowels/solid bar sticking out of one side. on the other side I would put two very small casters and instal the pulley on the wall so that the weight rides up and down on the wall. my bucket-o-cement gets to swingin when doing lots of caned drilling cycles. so far it hasn't hurt anything, but I don't like seeing it.

[ImagineRobots]

very nice! what was the total cost? I'm having a hard time convincing myself to make one since it will put my tormach purchase further away.

........

Thanks. Major costs of power drawbar:

footpedal $34 ebay
12V 5 port solenoid $50 ebay
exhaust mufler x 2, Allied Electronics $10
Fabco 4" dual stage pneumatic cylinder $45 ebay
Drawbar $38.50 Tormach
Bellevilles x 6, $15 Tormach

Total approx $200. Add another $50 for things liking hoses, hose fittings, shaft collar, spacers, springs, washers, nuts, aluminum base plate, threaded rods, etc.

For ~$250 you have a system for the X3 mill that you could adapt later for a Tormach since it basically uses the same drawbar and Bellevilles. You'd need to make a new base plate and use longer threaded rod.

[WOTDesigns]

at that price it's damn tempting... just so many things to do.

[ImagineRobots]

at that price it's damn tempting... just so many things to do.

The key is to get a cheap Fabco (or equiv) multistage pneumatic cylinder from Ebay. Looks like they are harder to get now - probably due to folks on CNCZone building PDBs

[viking45]

Hi!
Can you, please, specify the air cylinder more exactly.
I probably have to order it,
we have here ( Finland ) very difficult to find used air cylinders.
Sorry for my bad English
viking45

[ImagineRobots]

Hi!
Can you, please, specify the air cylinder more exactly.
I probably have to order it,
we have here ( Finland ) very difficult to find used air cylinders.
Sorry for my bad English
viking45

See attached file.

I got the Fabco MP4x1-2-1-FF-MR from Ebay for $45 + $30 shipping
This is the 2 stage extend, 1 stage retract, 4" diameter cylinder with
1 inch throw

Ideally, you would want a 3 stage extend, 1 stage retract, 4" diameter,
1/2" throw
MP4x1/2-3-1-FF-MR

Tormach started with a 2 stage 4 incher but switch to 3 stage after
beta testing because some users compressors with 100 PSI couldn't open
the draw bar. In actually, using the antiseize compound would have
helped out a lot so the 2 stage is good enough but not ideal.

Also, by dropping the throw from 1 inch to 1/2 inch your stack height
doesn't get too large.

[viking45]

Hi!
Thank You "ImagineRobots". That was a quick reply !!
With your specifications I can go through the European
manufactures or order one from US.
I'm waiting for a packet from Tormach with Drawbar and Belleville washers.

We have midnight here
Regards
viking45

[viking45]

Hi!
The Drawbar and Belleville washer are here and were not expensive. But the pneumatic cylinder is. Fabco factory price is $324 + delivery to Finland etc, total costs will be about $500.
So, do I really want it ??
viking45

[WOTDesigns]

There are a LOT of cheaper ones with longer throws. 500lb force against a lever with a 4:1 ratio is still 2000lb. not much to fabricate, just a pivot point an inch away from the draw bar, a 5.5" bar with a half inch hole 1.5" from one end, and the cylinder pushing down on the long end.

measurements are for simplicity as the throw should equal the actual arc travel of the long end of the rod. fulcrums are fun. mechanical lever multiplication is linear and can be easily calculated

[ImagineRobots]

Hi!
The Drawbar and Belleville washer are here and were not expensive. But the pneumatic cylinder is. Fabco factory price is $324 + delivery to Finland etc, total costs will be about $500.
So, do I really want it ??
viking45

I guess it isn't cheap shipping to Finland from the US!

Keep checking Ebay. There is a 5 inch bore, 3 stage listed for $73 (MP5x1x3x1ft-NR). It is a much larger bore than what you need but you can just reduce the PSI to the cylinder. Maybe you can also take it apart and modify it as a 2 stage.

[viking45]

Hi!
Thank you for advice's. I'll keep on seeking, in the meantime I'll make dimensioned drawings of the Sieg kx3 cnc Mill Headstock...if anyone has not already done it.

viking45

[viking45]

Hi! ImagineRobots
Is this thread still alive? Does your PDB still work well? I have not put the project aside, but slowly continued.
I believe I have soon something to show, if there is interest anymore.
Regards
viking45
Finland

[ImagineRobots]

Hi! ImagineRobots
Is this thread still alive? Does your PDB still work well? I have not put the project aside, but slowly continued.
I believe I have soon something to show, if there is interest anymore.
Regards
viking45
Finland

She's still working great. My favorite part of the mill is the PDB and Tormach TTS holders. I'm sure folks would like to see your progress.

[viking45]

Hi!
My version is now under testing.
Here is a video of my Power Drawbar:

Power drawbar - YouTube

Also here is a couple photos of my ringlight.

Regards
Viking45

[ImagineRobots]

Hi!
My version is now under testing.
Here is a video of my Power Drawbar:
......

Also here is a couple photos of my ringlight.

Regards
Viking45

Viking,

Nice ring light and welcome to the power drawbar club! It looks like you managed to get a 3 stage, 4" diameter, 1/2" throw Fabco cylinder shipped to Finland. I see you used a nice blue anodized bottom plate that looks like 3/4" thickness. I don't see any plate flexing from your video unlike my 1/2" thick plate.

Next you'll be getting a collection of TTS holders for all your cutting bits. Tip: lot's of folks have purchased a set of 10 ER20 collet holders for $99 off of Ebay plus shipping. Great price, really high quality and works with the TTS system. Ebay seller is bsello168 and he ships international air. He now has ER25 and ER32 sizes.

Here's the thread on CNC zone:
http://www.cnczone.com/forums/tormac...et_chucks.html