VERY generous calling any decision made by proxxon a "design" decision. Well done btw.

A well thought out and designed nut expertly crafted. But with one glaring flaw. With the "split" portion of the nut and adjustment screws placed as they are, it will make adjusting the backlash difficult or impossible with the cross slide in place on the saddle. You could flip it around so you could reach the adjustment screws with a long hex key from the rear of the saddle. But this would raise a major issue, when feeding a tool into the work using the cross slide, only the thread in the smaller "split" portion would be in engagement with the feed screw. To solve this you could reverse the design of the adjustment screws, so to speak, so that instead pulling the "split" portion towards the main body of the nut they would push it away. Then the threads in the main body of the nut would be in engagement when feeding into the work. You could do this by drilling and tapping two holes in the "split" portion, and use two set screws to push into the main body. To prevent rotation of the "split" portion, you could have the points of the set screws resting in dimples on the main body, or better yet, use dog point set screws (set screws with a cylindrical portion on the end and a flat tip) with the tips engaging into holes drilled into the main body. But a very good job, none the less. With such little backlash, you could easily ignore it except for the most precise of work. Have you ever considered putting ball oilers in the saddle, cross slide, and compound (top slide)?

@Michel-Uphoff

3 ай бұрын

I knew that when I designed the nut, but decided it was unimportant. In practice, I adjust the play once every six months or so, when I have already taken apart the saddle, cross slide and component slide for servicing

@gretah3969

3 ай бұрын

@@Michel-Uphoff Hopefully I didn't come across as rude. I didn't know if you were aware of it. I would hate for you to go to all the trouble of making an adjustable nut only to find out you can't adjust it, lol. Your design is definitely superior to the stock nut, disregarding material choice. I actually had come up with a similar design, the "push" design described above, because I found the standard design of split nut, like that on the Proxxon, to be theoretically flawed. Since the standard design uses a nut slit almost all the way through, leaving a small "hinge" on one side of the threads and a set screw pushing the slit open on the other, adjusting for backlash would create an angular misalignment between the split portion of the nut and the leadscrew. Potentially this could cause the threads to only be in engagement on one half of the circumference or even only at one point, causing accelerated wear. The angular misalignment could also cause binding or drag issues, limiting how much backlash could be taken up before the screw becomes too difficult to turn. How much of this causes problems in practice, I don't know, since even well known machine tool manufacturers used/use the standard design.

Lovely work ❤

I've recently bought a used PD400 and it already came with a cross slide nut made of brass. They must have changed bits and pieces over the years.

@Michel-Uphoff

6 ай бұрын

That's new to me! Thanks for the info. So there is no nut-case anymore. Maybe they watched.. 😉

The PD400 was on my short-list of lathes a while back. I’ve always had Emco but wanted a new, quality minimalist lathe. Proxxon, Wabeco, and Klippfeld were three options of alleged quality, but Klippfeld died, and with Proxxon being relatively small, and the price way too close to the larger and more powerful machine from Wabeco. I bought their D2400 bar-bed machine direct, to suit my model engineering needs. This machine has been ideal. In 2.5 years of intensive, and highly demanding miniature machining, I have not repaired, renewed, upgraded, or modified a single thing. Reliable, soundly built, and extremely quiet, due to toothed belt lead-screw drive. (It is used in a studio situation). The design, other than a few quirks, is excellent. The open-architecture allows face and hands in close for fine work, and short focal distances. The very thick, solid nature of the compound slides, the generous travel, smooth, precise, and fine lead-screws have extreme sensitivity. The MASSIVE contact area of both saddle and tailstock around the (swarf-shedding) bars ensures long service life. The 1.4kw variable speed is smooth and full power available even at the lowest speed, and also contributes to excellent finish. Wabeco are a strange company, who seem to have little interest in promoting themselves, a stilted approach to client interaction, and defective approach to appointing suitable agents to properly represent their rather good product. (At least in the Australasian market). Given the unacceptable quality of previous Proxxon product I have owned, I am not surprised at your trail of underwhelming experiences. I once hoped the “German Made” aspect of the PD400 would be an assurance of a precision and quality, but it just seems way overpriced, and under-engineered. Your excellent and interesting videos on the topic shows me that I made the right choice. Sadly, even German manufacturers are compromised today by the race to the bottom generated by China, and cut corners to compete. It seems the best of Taiwanese is now as good as “German Made.” Proof of the demanding nature of our work can be seen on; www.modelautofabrique.com

@Michel-Uphoff

Жыл бұрын

Thanks for your detailed response, very helpful! I hope behemothinferno will read along and take advantage of it. I did consider the Wabeco D2400 at the time, but little information was available about it. Less positive points with this lathe as far as I remember were: - The price, including gear set, the machine was sold here in the Netherlands a few years ago for € 3800 and for that amount I could purchase the Proxxon (€ 1990) with a heap of accessories. - I am not a fan of the design of the bed. Can you minimize the play between carriage and bed if need be? - And, important to me, I sold my trusted 35 years old Emco compact 5 partly because I really wanted a carriage handwheel for moving the carriage quickly. I was so fed-up with turning that right hand wheel endlessly.

@deems5937

Жыл бұрын

Yes. My Emco C5 irritated for that reason. I disconnected the lead-screw, and pushed the carriage to the desired position, locked, and used the top-slide. Schaublin style! I also had a Maximat for larger stuff. There were more reasons for me shedding the C5 than that though! Emco were killing off the “hobby” machines then, and were in a quality hole, cheaping out, and sourcing parts from China. I just start the D2400, flip the lever and let the saddle glide along as I set up tool/holders etc. As stated, the “Open architecture” of Wabeco bar bed machines allows for more hands, face, and fiddling room, along with my use of tiny versions of tangential tooling, and several home built Norman Patent column style tool holders reduces frantic hand winding in any direction. The tangential tools are brilliant, only three turns back on the very long cross-slide to clear the tailstock chuck for drilling etc. No adjustment between saddle and bars. But I can’t detect one micron of wear so far on the bars, and absolutely zero play anywhere, saddle or T/stock. And I reiterate that the sliding contact area is Massive! Some of these machines have been in use for forty years without replacement parts. The bar circumference.=95mm x saddle length=140mm x2 bars is sharing the load very well indeed. With regular PTFE application also. From Australian suppliers, closest to New Zealand where I am, (for now!), the PD400 was $5,400, the Wabeco D2400 direct was $7,200. (New Zealand dollars) Freight cost from Europe to Australasia are significantly higher than Germany to Netherlands! I have always held that you can do very small work on a larger machine, but not the other way around. (Assuming reasonable quality of both machines). I have done many jobs on the D2400 machining or drilling and tapping/threading to .8mm . I have a .8mm wide parting tool and cleanly and perfectly machine material on the D2400 with exacting precision. Nice machine! Because I am very busy making model artwork, I have no time, and no patience for faffing about with up-grading, down-time, or repairs. Some see it as a hobby, and if it keeps them off the streets, that’s good! (Joke). I could never own or use a conventional style of lathe again. (I have no affiliation with the Wabeco Company, and I paid for my machine) Anyone interested in my experience with this machine; dmjeffries3@icloud.com

Years ago I had my PD400 cross slide stuck dead. Had to cut this nut in two in order to got cross slide moving again. Absolutely no lubrication from factory was the case.

nice music as usual

very nice work good idea on placing a mirror on the angled section of the mill speaking of the mill what DRO are you using on it? is it only two axis?

@Michel-Uphoff

Жыл бұрын

I have a two axis Ditron with 0,001 mm resolution.

HI Please tell me where you bought the locking levers for the tool turret? Thank you

@Michel-Uphoff

2 ай бұрын

Google for clamping levers, clamping handles. There are many brands, e.g.: norelem.co.uk/en/Product-overview/Flexible-standard-component-system/06000/Clamping-levers/c/21358

Hello there.i have the same lathe as you and i'm really curious ,if you would be willing to make one more that kind of a nut,for me? Of course,for a good price?because I see,you have all tools to make it.

Nice work! I made a similar, but much smaller, pressure nut, split nut, whatever it is called, for my PD250 lathe. That was a challenge! The channel in the saddle is very narrow on the PD250 so and I had to mill it a little bit to make it's profile square. I obtained similar backlash. The washer bearings for the saddle lead screw need to be replaced with thrust ball bearings, but on the PD250 there is simply not enough material to sacrifice to make place for them. Is the PD400 saddle made from steel or diecast Zamak? On the PD250 it is Zamak, soft as cheese, but a bit harder than aluminium. The casting is so thin that practically any modifications are impossible. I want a better steel saddle, and the same for the base of the compound. The two adjustment grub screws for the steel plate made me nuts. They pressed against the paint on bottom of the saddle! I removed them and filled the cavities in the saddle with two milled aluminium blocks, and added some brass shims. Then I tightened the two screws that holds the assembly together and got rid of most of the slop. The right aluminium console that holds the lead screw can be improved. I made a replica and countersunk the left side to acomodate a 5x10x4 mm thrust ball bearing, inserted a bronze bushing into the hole, and faced off 4 mm from the hand wheel hub to make room for another bearing. To improve stability I ordered a 30 mm thick fine grain black granite slab (Nero Azoluto) and made two 20 mm aluminum blocks to put under the feet for elevation. It is really important to bolt the machine onto a solid base plate. Oh my, the improvements needed on, I believe, any Proxxon is a never ending story. They look so nice, but I have mixed feelings about their "sandwich design philosophy": Aluminium | Steel | Zamak | Steel | Paint | Aluminium | ... Btw, a collet chuck is a great investment for these lathes! I bought a MK2-ER20 chuck from Arc Eurotrade for my PD250 that works fine. But no through hole of course.

@Michel-Uphoff

2 жыл бұрын

Thanks for the compliment Paul. The PD400 saddle is made from steel, but the compound base is from zamak. It shouldn't be too hard to make a steel one with a 'real' nut. Maybe I will do so in the coming months. What a coincidence you're writing about a collet chuck. A few day's ago I ordered an ER40 chuck with morse taper 3 an the complete collet set. Hope to receive it in the coming weeks. I made the choice for the 'B' type with M12 threading. I'm thinking about machining a hollow draw bar, so I have a (very narrow, max 7 mm or so) though hole.

@paullehmor982

2 жыл бұрын

@@Michel-Uphoff A hollow draw bar sound like a good idea! You don't need much draw bar tension anyway so it should do fine. ER collets are great. They have good concentricity, and each size can handle a span 1 mm below it's nominal size. For short work pieces I use to back up with a dummy behind to fill up the collet length, ow it will not grip evenly lengthwise. It is also more finger friendly to work near a collet, for example when deburring with a file or using emery paper. Arc sells collet nuts with an integrated ball bearing so the nut can be tightened without rotating the collet itself.

@marcoam2610

Жыл бұрын

Hello @Paul Lehmor nice to read you here again. I'm also a PD250 user and after turning 0.1mm diameter less at the tailstock end to a distance of 83mm and after i held a dial indicator against a clamped workpiece and then moved the cross slide back and forth in Z axis direction...I get a few hundredths difference in X direction (this is clearly to too much play in the cross slide, it must be lifting - not visible to the eye), I disassembled everything to measure everything accurately. The machine bed is fortunately ok (precisely ground). Next, the cross slide (and its guide play adjustment). Michel said it: The play adjustment option from the bottom (especially with the larger and heavier) PD400 is an absolute disaster, it must be accessible from above by adding up to 4 grub screws in new locations - OR - just your approach, which I find better the more I think about it. Also elegantly solved, just because with the PD250 there's hardly space and meat (enough solid material) for further modifications. So thanks for the idea! Then, the bottom plate (24002-03 - 23). It measures L69.40mm x W53.95mm x 5 and i would like to rebuild the plate more massively & precisely (tighter fit, final fit maybe with fine grinding paste), something like L70-80mm x 54.95 (the inside guide distance of the bed seems to be 55mm ±0.04) and with a thickness of 6-10mm, . Ordering the (bigger, thicker) PD400's cross slide bottom plate (24400-03-31) and modifying it was another idea. What would you say is the steel material of the bottom plate? I do not want to use some harder steel as a friction partner and increase the machine bed wear. Could it be S 355 (1.0577, unalloyed general structural steel)? greetings from CH

@paullehmor982

Жыл бұрын

@@marcoam2610 Interesting to read your observations! I am not a steel expert but I agree it's wise to consider wear when choosing material for a new bottom plate. Maybe some extra wear at the bottom side of the ways is not that harmful? It's important to obtain a smooth travel of the saddle of course. I drilled a hole in the tail stock bottom plate without problems, it seemed to quite soft. So maybe some free machining steel would be suitable? My main concern is two major weak spots - the Zamak metal in the saddle itself, and the compound. I am thinking about machining a new compound from steel, but a new steel saddle would probably be beyond my current capacity. One also has to consider the overall space limitations in the lathe, which restricts the room for innovative solutions when redesigning the saddle. My PD250 has degraded substantially. I can't do any kind of smooth taper turning any more. Moreover, the compound is very hard to lock. It's really annoying when it starts swiveling during a parting operation. A temporary solution is to put a piece of emery paper underneath to keep it still. Another weak spot is the cross ways on the saddle, in particular the left side. Maybe mine has worn out. I machined a 80 mm aluminum back plate for mounting the three jaw chuck, and the collet chuck, on my rotary table. There was some unexpected run-out. I skimmed the top face slightly with a shell mill and the run-out was eliminated! The cause: The facing operation on the lathe had produced a conical shape! I suppose the cross slide does not travel true anymore. No gib adjustment in the world can fix this. Facing without chatter and spiral traces all over the surface is only possible with POM. No wonder, considering that the saddle is made from Zamak. I have failed to protect the ways sufficiently and they seem to be worn out. Recently I have been looking at the Sherline lathe. It's to small for some of my needs but I think it looks interesting. It is targeted for precision work, and apparently good enough for Clickspring. In my country, Sherline is imported by an aircraft support company, which might be a sign of quality? I have to find out.

@paullehmor982

Жыл бұрын

@@marcoam2610 I should add that my bottom plate solution, with shims, works quite well. Maybe I adjust it once or twice a year, and of course I have to turn the lathe upside down and disassemble the cross slide to repack the shims. But this can be done as part of regular cleaning and overhaul.

Profesional esti peste virful media cu mult la care adaugam faptul ca lucrezi cu " turnatele din aluminiu sub presiune pentru maxima precizie""" .fara sa te plingi de "calitatea lor . Si faci lucruri adevarat uimitoare ,fata de restul care cum le cumpara le si "refurbisaza " far sa produca ceva cooncret.Cinste tie esti mare meserias.

@Michel-Uphoff

5 ай бұрын

Multumesc pentru compliment!

@EugenBadau

5 ай бұрын

Osa urmaresc cu placere tooate postarile sint educative si profitabile@@Michel-Uphoff

This sort of operations are expected for basic Chinese made mini lathes and not a lathe that is supposed to be of German design and currently costs in excess of £2700.00 in the UK. I guess this one is also relegated to the categrory of WIP ( work in progress ) lathes. Not good. I am also surprised to see the use of Metric Trapezoidal form in the lead screw of an expensive ' precision ' lathe. These are fine for miniature lathes such as Sherline or Taig but not here. They should have used ACME thread form and Oilite as the material for the nut.

@Michel-Uphoff

Жыл бұрын

Basic Chines lathes are not nearly as accurate and well-made as this Proxxon. So, there is way more work to do (if even possible) to get those lathes in a decent shape. However, why Proxxon provided an aluminium nut, it beats me...

@HM-Projects

Жыл бұрын

@@Michel-Uphoff Proxxon is all made in China these days and built to a price unfortunately I've not seen the same quality I'd expect from German machines. I did consider the PD400 but ended up buying an Optimum clone for less than 1/3rd of the price. It's a much heavier and sturdier machine and it needed very little TLC / modifications to be put into use.

@Michel-Uphoff

Жыл бұрын

The handheld tools are made in Wecker, Luxembourg. The mills and lathes in Klausen, Germany. It is however true, that some parts are imported from China e.g. the spindle motor and electronics for the FF 500/BL mill. You can buy crap form China, but also some of the most precise instruments available.

@michal304

Жыл бұрын

@@HM-Projects What clone did you buy? Thanks

@HM-Projects

Жыл бұрын

@@michal304 Paramount Browns FI 550