Placement and overhang of Deckel model 6017 380mm rotary table

[bsg]

I did some checking on the sizes available of Dura-Bar. There is one size that would make an excellent sub-table for a Deckel Rotary Table: 2.5" x 8.25". It comes in 72" lengths, which would yield (5) 14" long pieces. The base of the rotary table is a little bit less than 8"x12", so an 8x14 sub-table would work fine. The 2.5" height would also be enough to raise the handles and index plate above the surface of the mill table, and the top of the rotary table would end up 6.5" above the mill table. That also means that on an FP2NC, the top of the rotary table would be about 3" above the center-line of the horizontal spindle with the table at the top raised as far as it will go. Which is good, it would allow a reasonable size cutter below the bottom of something on the rotary table (a limitation I ran into earlier this week using 4" parallels).

If anyone else would be interested in going in on a purchase let me know.

-Dave

I would be interested depending on price?

Kevin

 

[AlfaGTA]

Dave:
What you need is to forget the riser for that FP2NC and fit smaller "tool makers" table...the one with the encoder for the rotary motion and indicators for tilt and swivel....
Then you will have the rotary any time you need it without needing to mount any other hardware.....

Cheers Ross

 

[ballen]

I did some checking on the sizes available of Dura-Bar. There is one size that would make an excellent sub-table for a Deckel Rotary Table: 2.5" x 8.25". It comes in 72" lengths, which would yield (5) 14" long pieces.
<SNIP>
If anyone else would be interested in going in on a purchase let me know.

Dave, I'm curious how much that costs in the US. I estimate the weight at around 195kg = 428lbs. Here in Germany if I get a really good deal on cast iron I pay about 3 Euros/kg, otherwise about 2x to 3x that. So a piece like you describe would be between 600 and 1500 Euro. Cheers, Bruce

 

[DennisCA]

I can't even buy cast iron in Finland, unless I want to spend thousands of euros on 6m stock and the like. Last time I had to order from germany via ebay so I could get a smaller quanity of square bar
(new leadscrew nuts for my lathe).

 

[ballen]

I got lucky on my last purchase, found three 250mm diameter x 40mm long pieces of GG25 for 120 Euros plus another 20 in shipping. For 47kg (about 100 lbs) that's a great price. I'm using it for lapping plates, visible in my first post in this thread.

 

[TNB]

I agree that dynamic loads are naturally worse than static, but my comment about the action of weight on canlilevered members over the long run was based on a personal observation.

On my first FP3, the mounting plate of the universal table was clearly distorded. The plate was not flat anymore and looking it from the top, it clearly showed a deformation caused by forces pulling it forward.
Can't remember the numbers, but it was a really a lot and there was no evidence of shock or accident.
Of course, I can not be sure that the previous owners didn't use it for years to machine 2000lbs....
Nevertheless, that plus the countless things I read about BP's tables sag had me thinking about static weight beeing a possible problem (to some extend).

To get back to your lapping plates Bruce, weren't the 200mm y-axis travel of the FP2 sufficient to cover half of their surface, then rotate them 180° with the rotary thable and machine the other half ??

 

[ballen]

Hi Tien,

On my first FP3, the mounting plate of the universal table was clearly distorded. The plate was not flat anymore and looking it from the top, it clearly showed a deformation caused by forces pulling it forward.

I have seen similar things, for example when scraping the bottom of a vise mounting plate (rotation plate) flat. Could it be that the mounting plate was distorted because it was mounted on the machine with a chip underneath, and then the owner tightened it down hard? That's a very different magnitude of force than a couple of thousand Newtons spread over the surface of the plate.

To get back to your lapping plates Bruce, weren't the 200mm y-axis travel of the FP2 sufficient to cover half of their surface, then rotate them 180° with the rotary table and machine the other half ??

Yes, that's exactly what I did. I first mounted them on the table directly (no rotary table) but found that the setup time to rotate them 3 times was longer than the cutting time. The rotary table eliminated that setup time.

By the way, I'm now using a mist cooler that I bought on Ebay earlier this year. It uses pressurised air and some kind of plant oil that the manufacturer says is "bio" and not harmful to people. I cut 20 or 30 meters of slot with the saw and as far as I could tell, it was about as sharp at the end as it was at the start. Also kept the black dust under control, as far as I could see. In the past I would have used flood coolant and then spent an hour cleaning up the mess afterwards.

Happy New Year!

Cheers,
Bruce

 

[Peter from Holland]

I do not think time is a factor in this You could check the base stones of the pyramid of cheops
Wear is from moving Not from static weight over time IMHO Or so little it is undetectable for us Corrosion is a factor though But getting the weight off will that reduce corrosion or the opposite

Peter

 

[rimcanyon]

Dave:
What you need is to forget the riser for that FP2NC and fit smaller "tool makers" table...the one with the encoder for the rotary motion and indicators for tilt and swivel....
Then you will have the rotary any time you need it without needing to mount any other hardware.....

Cheers Ross

Excellent advice. The problem is finding such a table for an FP2NC. Especially here in Salinas, Deckels don't grow on Brussels sprouts stalks or even on Artichoke plants. If I could find one I am sure it would have a new home.

 

[rimcanyon]

Dave, I'm curious how much that costs in the US. I estimate the weight at around 195kg = 428lbs. Here in Germany if I get a really good deal on cast iron I pay about 3 Euros/kg, otherwise about 2x to 3x that. So a piece like you describe would be between 600 and 1500 Euro. Cheers, Bruce

From memory, this casting weighs around 60 lbs per foot. I can't get the Dura-Bar GX page to load on my old Mac right now, but that is confirmed by cast iron density: 2.5x8.25x12 x .26 lbs/cu. in = 64.35 lbs. or 29.2kg So a 14" piece would be around 75 lbs. or 34kg, and the whole 72" bar would be 386 lbs. = 175kg.

I have had no luck searching for the cost of the Dura-Bar, so I will need to call Monday. I have been told that it is possible to buy Dura-Bar sawed to length, so it will be interesting to see the costs both ways for a 14" piece. I also think that the actual weight after machining would drop by at least 50%, so it should be possible to end up with a sub-table that weighs around 35 pounds.

 

[AlfaGTA]

Dave:
One might be closer than you think.

Cheers Ross

 

[ballen]

So a 14" piece would be around 75 lbs. or 34kg, and the whole 72" bar would be 386 lbs. = 175kg.

That's right. I did my estimate using a specific density of 8 (good for steel) but the specific density of cast iron is 7.3, so my numbers are 10% high and your figures are correct.

 

[sneebot]

I am dealing with some similar issues with a large FP4 table that I recently received.
Previous owner had modified the mounting flange and lightened it for his application
(mounting on an FP4M).

I decided to machine a new flange from solid. Durabar is indeed available cut to whatever
size you want. Durabar is not very descriptive (or concise) as they produce multiple different
material compositions in both ductile and gray iron.

Below are an image of the original flange (~130# casting) and side one (so far) complete
on the remachined part (currently probably still north of 200#).

 

[rimcanyon]

Very elegant, Matt. It should be on display at the Guggenheim! I can imagine that as the front bumper on the Batmobile

 

[TNB]

Now that's a very nice repair ! Congrats !
One has to wonder how one could torch cut such a part to begin with... And for what benefit ? 10lbs at best ?

I do not think time is a factor in this You could check the base stones of the pyramid of cheops
Wear is from moving Not from static weight over time.

When I began talking about the possible dammages that could be caused by weight in excess, I not only envisionned wear (wich I think is pretty negligible for the use I have of the machine), but also plain deformation on the long run.
May be it's just an impression, but I don't think comparing the compression load exerted on the base of the Kheops pyramid and a traction effort on cast-iron box ways is totally relevant....

Dave:
One might be closer than you think.

Cheers Ross

Let me guess... Is it beige ?

 

[ballen]

Hi Matt,

Below are an image of the original flange (~130# casting) and side one (so far) complete
on the remachined part (currently probably still north of 200#).

That's nice work! I'm curious what material you selected for that, among the different varieties of cast and ductile iron. Did you pick a material that will bend/yield before it breaks?

Also (and this is a more general question for everyone here) can anyone tell me why these materials are so expensive? The world price for "scrap iron" (which includes steel) is about 250 US dollars/ton, so around 25 cents per kg. But from what I can tell, cast iron bar is a factor of 15 to 50 more expensive than this.

I had a quick look at a standard "production cost model" which is the spreadsheet here:
Steel Production Cost Model - Steel, Aluminum, Copper, Stainless, Rare Earth, Metal Prices, Forecasting | MetalMiner
From that, it appears that the raw materials (listed as iron ore) should be about 1/3 of the cost. So I would have thought cast iron ought to cost at most 750 USD/ton and not ten times that.

Cheers,
Bruce

 

[sneebot]

That's nice work! I'm curious what material you selected for that, among the different varieties of cast and ductile iron. Did you pick a material that will bend/yield before it breaks?

There is a description of grades here:
Peterson Steel - Providing Dura-Bar; Continuous Cast Iron Bar Stock Steel Alternative

This part is machined from:
Dura-Bar Grade 65-45-12
which is a ductile iron.

Ductile iron does bend more than gray CI, but does not have the
same level vibration dampening characteristics as the gray.

 

[AlfaGTA]

Bought large diameter (15") rounds from "Dura-Bar that were supplied with trepanned bores last year for a job to reline the friction surfaces of a 50's Ferrari drum brakes.
For that application i specified 80-55-6. (Stronger and better wear resistance over teh 65-45-12)
Worked a treat.....machined well and final results were better than original.

Cheers Ross

 

[thanvg]

... for a job to reline the friction surfaces of a 50's Ferrari drum brakes....
Cheers Ross

Sorry for the off topic guys, but I can't leave this uncommented. Does it feel like any other job Ross? Because this casual statement sounds completely exotic to me!
Well done once again...
(and thanks for sharing some of these projects here)

BR,
Thanos

 

[AlfaGTA]

Sorry for the off topic guys, but I can't leave this uncommented. Does it feel like any other job Ross? Because this casual statement sounds completely exotic to me!

BR,
Thanos

Thanos:
Here is a link to the job on the brake drum liners.......Some head scratching here to get this done.

https://www.practicalmachinist.com/...er-diameter-work-361987/?highlight=Brake+Drum

Cheers Ross