[setlab]

I've noticed that the handful of normal bt30 tooling with pull studs that I've collected hasn't been long enough to engage with the drawbar. Did dyna myte make its own proprietary pull studs or are these just really obscure obsolete ones used?

So far I've collected about 20 nice tool holders, I'm hoping to find some cheapo Chinese pull studs so I don't have to spend another grand on tooling.

Is there a pull stud model or critical dimensions I can search for on ebay to get some that work?

Is it possible to change or modify the DM2800 draw bar to accept more commonly found pull studs?

[2ferrous]

Yes.

You'll always spend too much on tooling.

I have attached the DM pull stud drawing for you.

Timothy

[setlab]

Yes.

You'll always spend too much on tooling.

I have attached the DM pull stud drawing for you.

Timothy

Thanks 2ferrous! I actually sent you a message seeing if you still had a drawing before I saw this. The 45 degree inside taper defiantly makes more sense than the 30 degree taper I've seen.

[2ferrous]

Recommended torque on the pull studs is 25 to 35 ft/lbs. I use the lower number.
I also put anti seize on the threads and face. Makes it real easy for switching them out later.
I haven't counted lately but my tool cabinet has over 250 tool holders in it.
At least 50 are dedicated to drill and another 50 to end mills.
If my program calls for any common drill, I just grab it off the shelf, enter the offset and away it goes.
I can switch up tooling and programs in less than ten minutes.

Timothy

[MrMetric]

setlab,
If you want to join me (and anyone else) we can make a bulk purchase and lower the price. Roland can supply them, but the more you buy, the better the discount, which is why I've been trying to hold off.

I've considered making my own, but I have to admit that I'm a little worried about it. By the same token, if I have them coded up, then I can replace them more frequently..... The bigger issue is that I've been really challenged on getting good retention force from the Belleville washer stack. I suspect that if you measured yours, it wouldn't have as much strength as you might think, although the 2800 is a smaller machine than the 4400 (my thinking being that you probably are not as aggressive).

Alan

[setlab]

setlab,
If you want to join me (and anyone else) we can make a bulk purchase and lower the price. Roland can supply them, but the more you buy, the better the discount, which is why I've been trying to hold off.

I've considered making my own, but I have to admit that I'm a little worried about it. By the same token, if I have them coded up, then I can replace them more frequently..... The bigger issue is that I've been really challenged on getting good retention force from the Belleville washer stack. I suspect that if you measured yours, it wouldn't have as much strength as you might think, although the 2800 is a smaller machine than the 4400 (my thinking being that you probably are not as aggressive).

Alan

Id like to get all 20+ of my bt30 tool holders pull studs, that kind of depends on the individual price though. If you have a potential group buy I'm interested.

If your washer stack isn't producing enough force try tightening the retention nut all the was down. Or measure how much room your washer stack area is and see if your missing any and can add more?

[MrMetric]

OK, I'll find out how much they are. They are not cheap though... Sadly, the Dyna uses a custom retention knob.

As for the stack... It isn't quite that easy. I've created a fairly elaborate spreadsheet, actually, to work out the optimum stack order, quantity, possible throw, etc.... But I have to measure how much power I can really get out of my piston. So far I haven't gotten it quite right. There is evidence of 'checking' on my spindle.

[funford]

As long as they also work with the 1007 im interested aswell. Depending on price naturally . Has anyone considered changing the draw bar to something more common like a Hass etc...... ?

[MrMetric]

They are about $28 each, but it depends upon the quantity. As far as I know, but would confirm, Dyna used a single pull stud for their designs. And, yes, it is custom to their machines, which really sucks because they were never a giant manufacturer. As such, when they went bust, nobody continued producing the studs because it wasn't like a Haas where you'd sell 50K of them a year.

I'm not sure how viable it would be to change just the drawbar. Internally, the spindle has to have a taper upon which the ball bearings (if you didn't know, this system uses a four ball bearings, not leaf grabbers) 'ride up' and grip the retention knob. You can't just change the position of that ramp, and that implicitly controls the timing and, therefore, height of the retention knob. Because all other knobs are shorter, you would need to lower the ramped area, which means adding a shim or some other material. It is an interesting idea though. I haven't really thought about it that much, but I'm pretty sure it would not be an easy change.

The other option is to make the studs with a CNC lathe. Once you've programmed it, you should be able to make them pretty quickly. This is actually what one of the vendors told me would make the most sense. He said you really didn't need to harden them, although most of the commercial ones seem to be. Given how scary a broken stud can be, however, I think I'd substantially lower the time in use before I replaced the stud. But... it is an option. At some point, the only way we'll be able to buy these studs is to have 2000 made, and we won't be able to afford that.

[setlab]

I think I remember 5 ball bearings. Here a schematic of what the internal spindle looks like for anyone thinking about building a new draw bar. It probably wouldn't be too difficult to do.

[MrMetric]

Yeah, actually, I think you are correct there. I wasn't sure if it was 4 or 5, but it is still academic. You cannot just extend the drawbar, or make a new bearing holder. Both would achieve the same objective of lowering the bearings. But this likely mess up the timing. Either the cross holes will fall too low, allowing the bearings to escape, or the bearings will not be forced inwards, thereby capturing and securing the holder. The idea is sound, but I am pretty sure that you will need to modify the spindle too, and that gets to be quite a bit more work.

The pivotal thing here, though, is what is the LONGEST knob you can find that is widely available. If it is fractionally smaller than the Dyna one, you might be able to get away with manufacturing a new rod or holder, thereby changing the required retention knob. But the Haas ones, as I recall, are quite a bit smaller.

[MrMetric]

I just took a 2 second gander at the drawing from Timothy against a common BT30 knob. There is about a 4.5mm difference in height between the mounting face and the top of the 45 degree bevel which acts as the ball bearing face. That means to get that particular sample knob to work in our spindle, we need to lower to location of the ball bearings about 4.5mm. Frankly, my gut feeling is that this is quite a bit. I suspect that we'd drop the bearing out the backside of the nut. But.... It *is* an idea worth investigating....

alan

[Sun God]

$27 ea and hundreds in stock ready to ship when I last ordered some from Retention Knob Supply about 12 months ago. You guys are crazy if you think it's worth the risk, time, and hassle of DIY'ing them when they're one phonecall away. Do you realistically need 20+ tools on a benchtop, manual tool change mill?

[setlab]

$27 ea and hundreds in stock ready to ship when I last ordered some from Retention Knob Supply about 12 months ago. You guys are crazy if you think it's worth the risk, time, and hassle of DIY'ing them when they're one phonecall away. Do you realistically need 20+ tools on a benchtop, manual tool change mill?

We need all the pull studs!.... For reasons

[MrMetric]

$27 ea and hundreds in stock ready to ship when I last ordered some from Retention Knob Supply about 12 months ago. You guys are crazy if you think it's worth the risk, time, and hassle of DIY'ing them when they're one phonecall away. Do you realistically need 20+ tools on a benchtop, manual tool change mill?

If they are available then I’d never make them. So not crazy. It is interesting though. When I contacted RKS they said they didn’t have any! And that was at about the same time. Strange.

[Sun God]

If they are available then I’d never make them. So not crazy. It is interesting though. When I contacted RKS they said they didn’t have any! And that was at about the same time. Strange.

Retention Knob Supply item 341-14, they had hundreds in stock as of August 2019 at $26.46ea

[MxcrossPortugal]

Good afternoon my friends, My name is fabio seabra alive in portugal, owner of a motorcycle shop and workshop, Mxcross.pt Portugal,

I recently bought this machine DYNA MYTE 2800 for my workshop, would you like someone to help me get it working on cnc connected to pc, or if the easiest thing would be to convert to mach3 program?

I would very much like you to help me please my friends,

In Portugal there is very little knowledge

[funford]

Yes I'm definitely crazy. Do I need them? Probably not, I have ATC on my system but its probably going to be like the time I had to have a threading gearbox on my lathe and it took me an extra year to find one with it and I have used it less then 5 times.

[8sigma]

You don't need to tighten them to like 80 foot pounds or use red locktite (like some holders I bought). a dozen should do you. Money well spent.