Bought Bridgeport Clone - Now Getting it Set Up for Basic Machining
- Thread starter bulletpruf
- Start date
Cruzan80
Well-known member
Just found this from Tormach, about researching R-8 torque specs.
Link to the document: https://tormach.com/media/asset/t/d/td31090_toolholding.pdf
So the pin is only designed to help take the drawbar up to 40ft-lbs, and the taper mating surfaces can sustain torque of at a minimum 600 ft-lbs. So having the pin stop the collet from spinning seems like it is only needed when you are unable to get the tapered mating surfaces to "grab" hard enough for the 40ft-lbs of tightening in the first place. If you can torque the drawbar to 30ft-lbs (40 in extreme conditions) without a pin, it doesn't do anything.
Link to the document: https://tormach.com/media/asset/t/d/td31090_toolholding.pdf
Steve from Socal
Well-known member
My calibrated arm is set to keep the tool or work piece from spinning. You can mock my words and do as you wish. The spindle or work holder that spins collets is not as true and the gauge length may not be to spec but you do you.
Cruzan80
Well-known member
Not mocking you, but if you are using a "calibrated arm", by definition it isn't necessarily being drawn to its designed torque (why torque wrenches exist). Found just above where it the drawbar is designed to normally get tightened to 30ft-lbs, and the pin isn't used for anything but alignment. Or are you saying the tapered edges from the collet to spindle nose are not as true if there isn't a pin stopping rotation? It doesn't do anything for alignment in a "nodding" action...
Not sure where the pin helps add significatly to the equation in this. Not saying it doesn't add anything, just not sure where it is invaluable. For example, it is easier to have a pin in and tighten the drawbar, but saying you can't tighten it without a pin installed is like saying you cant loosen/tighten wheels once you lift a car. It is possible but more difficult. Nothing I know about has the pin helping collets not spin once they are in use cutting.
Not sure where the pin helps add significatly to the equation in this. Not saying it doesn't add anything, just not sure where it is invaluable. For example, it is easier to have a pin in and tighten the drawbar, but saying you can't tighten it without a pin installed is like saying you cant loosen/tighten wheels once you lift a car. It is possible but more difficult. Nothing I know about has the pin helping collets not spin once they are in use cutting.
Steve from Socal
Well-known member
Without a pin/key you are relying on friction to tighten the collet, once a collet spins in a spindle there "could be' damage to the taper in the spindle. I have used tools without pins and they can be a pain to tighten with a tool clocked and yes the torque is not high but do you know the torque you exert is not just draging the collet around the spindle?
Cruzan80
Well-known member
Because if the collet is spinning, it isn't registering torque. Torque is a resistance to angular force.
If the drawbar is torqued to spec, it is not more or less likely to spin under use if there is a pin in it or not. Having a pin installed and a collet spinning in the spindle can easily cause more damage than with it not installed.
Again, my issue was with the quote of yours below. The pin isn't needed to get to the designed torque. You find it easier to do so with a pin installed. Others do not seem to need it to hit the same torque.
If you disagree with the bold, I look forward to actual evidence the pin helps a collet from slipping under load. I posted Tormach's answer above.
If the drawbar is torqued to spec, it is not more or less likely to spin under use if there is a pin in it or not. Having a pin installed and a collet spinning in the spindle can easily cause more damage than with it not installed.
Again, my issue was with the quote of yours below. The pin isn't needed to get to the designed torque. You find it easier to do so with a pin installed. Others do not seem to need it to hit the same torque.
If you disagree with the bold, I look forward to actual evidence the pin helps a collet from slipping under load. I posted Tormach's answer above.
My Bridgeport pin is stuck to a magnet somewhere someplace safe.
I’ve always wire brushed the drawbar threads and chased my collet threads with a tap followed by a bottle brush and thinner. Keeping collets extremely clean and low drag is key! I generally hold onto the cutter with my thumb touching the collet when I’m tightening the drawbar. I know it’s not slipping because I’m checking for it while I’m tightening the drawbar.
Steve from Socal
Well-known member
I can only offer this, while the pin is NOT designed to take shock loads YES the pin prevents slippage of the collet. You guys may be thinking of a 1/2" end mill while I am thinking about a fly cutter or large face mill. In fairness, the tool should loose grip before the collet spins in any case.
I don't really have a dog in this fight, my machines are Cat50! Knock yourselves out!
Cruzan80
Well-known member
Tormach disagrees with you (post above quoted from their paper saying it is for alignment only). Sorry, going to take their word for it over yours, especially since the link I posted shows the testing data behind it. Unless you have actual test data to back it up, going to chalk it up as another "What I was taught...", not fact.
Steve from Socal
Well-known member
That's OK Tormach is not the firm I would seek out for industry standards. Their machines are toys.
Cruzan80
Well-known member
Any other R-8 standards you can find?
Steve from Socal
Well-known member
Why do the pins shear IF the collets don't spin?
Cruzan80
Well-known member
Never said collets can't spin. Just that the pin doesn't affect it (by the time a collet spins, the torque load is in excess of what the pin could handle anyway).
Or just admit your "evidence" is purely anecdotal, and move on.
Steve from Socal
Well-known member
Your 'logic' doesn't compute, the pin does increase the ability of the collet to transmit torque. The keyway in the collet squarely against the pin imparts an anti-torque arm to the collet. You fail to grasp the idea that the key/pin is an anti-rotation device. The only thing I found on a quick search for B-ports is a torque valve of 40~50 ft/lb. That the pin shears is a fuse in the spindle for an overload.
Cruzan80
Well-known member
If the collet is clean/dry, it can hold up to 3600 ft-lbs before spinning, via the link posted above. The friction fit between the tapers is the part that is "grabbing". At the point the taper lets go, the pin cannot withstand that pressure, and shears.
The pin is simply an "anti-rotational" device to ensure the collet doesn't spin when generating the appropriate torque to the drawbar initially. You even alluded to it when you were talking about ensuring the drawbar is torqued to spec.
Again, direct quote from a manufacturer.
At this point, it really feels like we are going in circles. You can disagree with what I have posted, but so far you have not provided any empirical evidence, beyond your personal experiences and logic. So please post evidence to support what you are claiming, or stop trying to say I am wrong.
The pin is simply an "anti-rotational" device to ensure the collet doesn't spin when generating the appropriate torque to the drawbar initially. You even alluded to it when you were talking about ensuring the drawbar is torqued to spec.
Again, direct quote from a manufacturer.
At this point, it really feels like we are going in circles. You can disagree with what I have posted, but so far you have not provided any empirical evidence, beyond your personal experiences and logic. So please post evidence to support what you are claiming, or stop trying to say I am wrong.
Steve from Socal
Well-known member
Well,
It seems that your right about the pin being to tighten the collets and I conceed that the pin is ONLY designed to tighten the collet. That was part of my questioning of not having a pin. While I agree the taper is what transmits the torque of the collet, I also think perhaps wrongly? That to get a good torque value on the draw bar insuring that the collet doesn't slip is important. I may also be thinking about R8 solid shank holders that don't have any spring to them. The short taper on an R8 spindle is not great for solid holders.
I don't want to sound like a jerk so I admit I was wrong about this, I still think from practical experience the pin does 'at times' absorb torque from the collet or prevents it from spinning. It may not be a text book case but the real world has plenty of exceptions. We are also assumming that spindle taper is in spec.
My machines all have drive lugs and don't use spindle collets, a 20HP machine is way different than a 2HP Bridgeport
It seems that your right about the pin being to tighten the collets and I conceed that the pin is ONLY designed to tighten the collet. That was part of my questioning of not having a pin. While I agree the taper is what transmits the torque of the collet, I also think perhaps wrongly? That to get a good torque value on the draw bar insuring that the collet doesn't slip is important. I may also be thinking about R8 solid shank holders that don't have any spring to them. The short taper on an R8 spindle is not great for solid holders.
I don't want to sound like a jerk so I admit I was wrong about this, I still think from practical experience the pin does 'at times' absorb torque from the collet or prevents it from spinning. It may not be a text book case but the real world has plenty of exceptions. We are also assumming that spindle taper is in spec.
My machines all have drive lugs and don't use spindle collets, a 20HP machine is way different than a 2HP Bridgeport
bugnut
ALLIANCE MEMBER
I've finished my popcorn, can we return to our regularly scheduled programming!
Firebrick43
Well-known member
A careless operator will shear the drive keys on a Cat 50 as well, I imagine the careless part is what your lacking!
TxSteve
Well-known member
"Owner had sold his house and moved to VA, so I was dealing with his neighbor......
Toughest thing today was getting in the shop where the mill was located. Neighbor forgot that he didn't have a key so he just removed part of the door frame and jimmied the lock open."
Hahaha - I hope you didn't just steal someone's mill that is on vacation.
Toughest thing today was getting in the shop where the mill was located. Neighbor forgot that he didn't have a key so he just removed part of the door frame and jimmied the lock open."
Hahaha - I hope you didn't just steal someone's mill that is on vacation.
bimmer1980
Well-known member
How's the setup of the mill going? Did you get a VFD yet?
I have a 7.5 hp rotary phase convter that works very well for my mill, lathe, iron worker, belt sander and drill press.
Just bored some holes for an excavator attachment I'm building. I didn't have a drill bit of the right size, so used the boring head attachment. Good enough for the....."boss"
Used up some 6013 rods I had....
I have a 7.5 hp rotary phase convter that works very well for my mill, lathe, iron worker, belt sander and drill press.
Just bored some holes for an excavator attachment I'm building. I didn't have a drill bit of the right size, so used the boring head attachment. Good enough for the....."boss"
Used up some 6013 rods I had....
OP
bulletpruf
Well-known member
I bought a VFD and all the bits that someone recommended a page or two ago, but haven't made any more progress.
Work has been sucking the life out of me, I'm in the middle of replacing the deck on my car hauler trailer, and bow season opens tomorrow, so I'll be in the woods all weekend. Wish me luck!
Scott
Last edited:
whateg01
Well-known member
Funny how stuff can come to a screeching halt when life gets in the way
TxSteve
Well-known member
Quick question - couldn't you weld together a pan to go under the base and take care of most of the oil leaking issues on the floor? 1/4" or so with 1" walls.....One quick piece of advice that most tend to skip over.
Kind of a two-parter: First is that machines like this live in oil. You cannot over-oil it, unless it gets to the point your socks start feeling squishy.
Second is that that oil ends up on the floor. No matter what, it drips down- and especially the center screw to raise the knee? There's a lot of load on that, and a good grease on the screw is important. But, the screw is open to the bottom of the casting- oil and excess grease drips down and puddles on the floor.
You've got what looks like a nice clean, relatively fresh and unsealed floor- you WILL eventually have a large oil-stained 'blast zone' around that machine. Not only from dripped oil, but also cutting oil brushed on the part and flung off on the chips.
If that's a concern, you might find it worth the effort to epoxy or otherwise seal the floor, at least in a fair area around the machine.
I really wish I'd done so before installing several of mine, but by the time I realized the necessity, it was too late. In my side machine room, despite my best efforts, spots of that floor are almost black with embedded oil- the only way I could epoxy it now would be to have it sawed out and repoured.
Doc.
86turbodsl
Well-known member
I thought you retired? Or was just the army only?
Firebrick43
Well-known member
That is always what we did in the shops I worked in.
SS pans with 1” side walls.
Sheared the sheet to size, bent up the sides on the brake and tig welded the corners.
Someone previously had made a single pan for two machines. The process engineers wanted to move the one but we could not take the other out of commission.
It’s real fun to cut a pan in half and the weld 4’ of 1” ss with a tig on your hands and knees.
Used up some 6013 rods I had....
6013? On an excavator plate item?
6013 is a low penetrating rod.
For excavator-sized plate, I think more like 6010 or 6011 or 7018. Unless the plate is higher strength stuff and then the rod usually goes to the higher-strength rods like 80xx or 100xx.
Last edited:
OP
bulletpruf
Well-known member
Retired from the Army, but have been working from home ever since I took the uniform off. Unfortunately, business has been really good.
bimmer1980
Well-known member
Yeah, the 6013 was just because I had a box of them I wanted to use up. A dumb, cheap purchase awhile back. Not a big fan of the 6013 as they like to run with the flux all over.
This is a small excavator bobcat 320. The amount of weld on here is probably more than sufficient for this particular application. If I break it, I'll weld it again.
I ran it tearing out asphalt this past Saturday afternoon and worked well. A four tooth of this style would be better. Maybe I will modify this a bit later.
DocsMachine
Well-known member
- Joined
- Sep 16, 2006
- Messages
- 1,848
-Certainly, and I've seen that done.
Ona Bridgeport or similar knee mill, however, the majority of the oil winds up running down the knee elevating screw. I didn't know that on my Grizzly (a bolt-for-bolt clone of a Bridgeport) and now the unsealed concrete under the base is pretty well soaked.
On the bigger Exacto (Spanish-made kinda-sorta clone of a Bridgeport) since it was up on hefty aftermarket rubber feet, I picked up an old cookie sheet at the local secondhand shop, and put that centered under the screw.
In a few years I'll have to fish that out and drain it, but it beats letting it soak into the concrete.
Doc.
Just out of morbid curiosity: what does your excavator weigh and how do you move it?
bimmer1980
Well-known member
I have a smaller tandem axle trailer that fits the excavator nicely (rated for 6990 lbs). The mini ex weighs about 3800lbs.
deck between the wheels or over? (assume something that light will easily fit between). Loading short track or wheelbase equipment scares the **** out of me.
bimmer1980
Well-known member
Here it is on the trailer. Has decent ramps, so it's not too bad to load. I also swing the dipper arm around for additional support during loading or unloading.
Nice size for close work. Most of all glad to see you have some nice, long ramps to be able to load safely. I still hear the scream from 25 years ago when our 15YO daughter tried loading a skid steer with bucket up front. When I got there the Boobcat was standing 90 degrees on it's counterweight between the ramps.Here it is on the trailer. Has decent ramps, so it's not too bad to load. I also swing the dipper arm around for additional support during loading or unloading.
Last edited:
OP
bulletpruf
Well-known member
Cruzan80
Well-known member
Show me some photos so I can see why this is such a good idea. Maybe I can learn something. I have been doing this a long time and I never would have considered doing what you are recommending. Help me out!!!
Our girls were on a race track as pre-teens. Big kid was in my workshop using tools since she was 3. She drove her first semi on her own when she was 12. Her eldest son was handling 6 way blade and steer in D5H when he was 5 - and he has been running tracked excavator on his own since 11. Also operates rough terrain crane now (at 13) - made transition from little lathe to making parts on 14x40 this summer. Same daughter in her late teens was racking up solo 2 FTDs in machine she had a hand in design and build.
Kids don't grow up to become confident, competent and independent adults without some kind of experience along the way. Our girls could play hours of competitive level piano from memory as pre-teens so learning how to operate vehicles and equipment was not much of a stretch. Part of that learning means making your own mistakes.
Cruzan80
Well-known member
Based on your response to me, I think we misunderstood each other. See PM.
txvwnut
Well-known member
I did something similar once with a Case. It had a few hydraulic leaks and needed a service and cleaned as the operating department doesn't know how to clean anything. I had the bucket off and the seat out of it so was I crouch straddling where the seat used to be working the sticks to move it into the wash bay where there is a drive on equipment lift. I think by now most of you see where this is going. I wasn't paying attention or didn't remember you load a skid backwards and proceeded up the ramp to the lift, well the skid tips backwards I fall backwards and give the sticks a solid reverse pull and back down the ramp we come only to end up tipping forward enough to change my crouching position and give the sticks full forward motion which sends the machine back up the ramps and well rinse and repeat for about three times of this before I could let go of the sticks.
I wish there was a video of it as I'm sure it was funny as hell.