Dillon XL750 First impressions / First modifications

First topic message reminder :

I ordered one locally about 10 days ago. Installed and started testing last Friday.

Needless to say, my primary interest was in new indexing system, new priming and fail safety mechanisms.

Initial observation is that engineering level is of typical Dillon. It is very raw, without much attention to technical details, too much reliance on free hanging self adjusting parts, and cutting corners for the benefit of production cost. The best example are primer feeding tubes that are installed into primer magazine. Plastic ends on tubes do not provide for consistent feeding. Out of 15 primers I loaded in my first trial, only 13 were loaded. I had to fish for two remaining with low primer rod. I then reamed plastic end with standard 0.175"+ reamer, and loaded another 10 - this time 9 made through. Called to Dillon technical support yesterday yelled suggestion by support tech that my primers might of been out of roundness, and then suggestion to cut off plastic end and install spare one included in package.

I also observed more disturbing thing, - couple of primers got flipped over. I'm interested to learn if any of the early adopters of the 750 had this happening! I also am not happy that during return primer bar crosses open area exactly where particles of powder can drop right into the primer holding cup.

Unfortunately older style tubes with brass ends would not work. So that is the first part I measured, drew and am getting turned out of brass.

Needless to say, I was disappointed that I cannot transfer tool head, that was setup on 650, to 750 without needing to make changes. However the good news here is that releasing two screws holding Powder Measure and rotating it enough to install tool head, was sufficient, and no additional changes to any of the dies was needed. That brings me to that fail safety rod and bracket. Latter seam to be a little bit off dimension wise (2mm, IMO) for the rod to drop down vertically as outlined in manual. And of course, bracket is sized the way, that if anyone wants to use Mr. Bulletfeeder's dropper installed on station 4 (while using station 3 for powder check), it is impossible! Powder measure with current bracket is seating about 10 degrees too far to the right, - this is the issue that Rick Koskela, The Mr. Bulletfeeder asked me to look into. The simplest solution to this problem is using fail safety rod assembly from Super 1050, p/n. 16811. I FaceTimed how it works to Rick, and he will take it to Dillon's folks. However I'm still going to re-design entire bracket for better overall functionality.

I implemented first modification on Sunday. I installed springs on both primer bars between body of the bar and plastic roller, so roller doesn't get stuck at the back corner of the housing. If anyone interested - in my local True Value it is Spring #9 ($0.59), and then cut to the proper size. Or in simpler terms, spring with ID 0.1875" and smallest wire diameter you can find.

I proposed this tread as a means of exchanging experience and ideas regarding this new press. I understand that there might be other forums, that are more specific to Dillon's equipment. I simply don't have time to follow up all of them. Feel free to propagate information.

AP

Thank you Steve!  Yes, I saw that.  It deals with shell plate over shooting or under shooting alignment, which also cause primer being seated sideways.  If we are to use a clock as a reference, that would be primer's edge being caught at 3 or 9 o'clock.  My issue is that primer get's caught at 6 o'clock because I'm trying to go fast.  Primer bar didn't finish alignment, and I already forcing primer up.  However you just gave me idea, that I'm going to check on tomorrow.  It is not adjustment of indexing, but rather adjustment to primer bar timing.

AP

jglenn21 wrote:Update on the brass tip for the 750 primer tube:

AP was kind enough to get me some to test on my 750 which is setup for 45.

Installation was a breeze.. I knocked the plastic end off my LP tube and fit the brass end on easily. On my tube the brass end was press fit. I simply heated it a bit and pressed it right on. Installed the tube and began to run Winchester LP primers thru the loader.  I ran a test of 20 using the primer rod with a 45 case on the end. All primers ran perfectly.. then I ran the same 20 back thru the primer feed without the rod. Again it ran perfectly including the last primer.

My impression is this is a perfect long term solution for the plastic tips Dillon uses.. while my 750 has been very good with the plastic tip installed at the factory. I have enough 550 experience(30 years or so) to know the plastic will wear/warp  and induce issues..replaced a few over the years on my 550s..

Very well done solution
I'll update this with real volume results after I load quantity of ammo

Off topic a bit, I understand the 650 tube has a brass tip and it will fit in the 1050. I haven't tried it yet but if anyone knows for sure if it will work I'd love to know. I haven't wrecked many of the plastic tips and have a few spares but if the brass tip would be a permanent fix it would be good to know. Seems like I read somewhere folks have done it and others said not to do it, just wondered if anyone has done it and how it worked out.
Thx in advance

blindshooter wrote:
Thx in advance

Brass ends on primer magazine tubes from 650 aren't compatible with 750.  This is the first thing I tried, and subsequently had to machine my own.

Well, I think I finally found the cause of flipped and sideways primers.  After forcing myself and slowing down I finished loading few thousand of various 9mm loads, and decided to switch and load some 10mm.  Problem with sideways priming got so bad that I finally gave up, tore press apart from the shell plate down.  And I mean apart, to the last screw and spring.  Here is what I found hiding in the frame of the press.




AP

That’s unsat.  Structural defect?

Wobbley wrote:That’s unsat.  Structural defect?

I don't think it is structural defect, Ashley.  Although area of the break is one of two load points, and force applied in the area in question might cause break.  However it is a secondary load point.  If you look at this quasi drawing - https://dilloncdn.com/manuals/dillon-xl750-manual-english.pdf main load point is in the area held by two #15 screw.  Break point is in the second attachment point held in the press' frame by screw #13.  Force is being applied vertically from top to down direction in parts #7 & #8.  All force needed is sufficient one to compensate Spring #9 in order to seat primer.  This is also the problem area I mentioned in previous post - slightest misalignment between above parts and hole in the platform causing primer flipping or sideways seating.  I see the design flaw here, but it is rather in platform of the press.  And corresponding part is piece of carbide ring pressed into platform.  Otherwise broken part is not simple to manufacture, and I understand the reason for cast.  However it might be not right choice for the material.  Truth be told this is probably one of the top three most expensive parts to manufacture in this press model.  Without a question it would be the most expensive one if it is machined.

Without digging deep into material resistance and calculations, I'd says that most probable cause is defect of molding / cast of this particular "specimen".  That will be answered after I get replacement part and run press through another 5-6 thousand rounds.  If there is a structural defect, it must happen again.  As I'm reviewing my notes and this post, I wasn't happy with press from the day one.  It just didn't feel right.  I can run both of my 650s and 1050 with two fingers at full speed.  750 was a replacement of going to gym (not bad thing these days, because gym is closed).  

All of the above is IMHO.  

AP

IMO, as a design, manufacturing Engineer and an amateur machinist... the design is asking for trouble.  You’re attaching at two independent surfaces.  Unless both parts are machined to tight control on the geometric relationship, there is no way to install these and not create a stress point.  When you get your replacement part, check to see it there is any gap between the other mating surfaces when each surface is installed and torqued.  Since these are castings you can only “pull up” .001 gap otherwise you need a shim.

Yep, that's correct.  I already cut few brass cases to make my "gap gages".  And these can serve as shims too.  That is what I use to shim tool heads on presses as well.
AP

Wobby you explain it in more technical terms than i could but looking at the failure it appears more side pressure than downward may have caused it. I'm going to take a look at mine tomorrow and see how close the fit actually is. Looks pretty easy to introduce stress when mounting the plate..

I'd "liquid shim" it.

I thought about this too, and I have good substance for that made by Locktite.  No go.  It must be disassembleable. For that matter I just answered Jimmy's PM.  In order to replace primer slide return spring half of the press have to be taken apart so primes system mount can be vised and roll pin driven out.  Give or take an hour job.  And very pleasant thing when it happens in the middle of the reloading.  Makes me wonder if designer does any reloading on his/hers own.

AP

They make Teflon release agent for that.

Give the frame and the screw a shot and it will come right back apart.

Let the "shim" bond to the die cast part.

I have to look into that.  I've never used it.  Thank you, Glenn!
AP

You could glass bed it just like bedding a rifle action..release agent on one side would work. Providing there is excessive clearance..we'll see

Miller-Stephenson makes the release agent I use.

https://miller-stephenson.com/chemicals/mold-release-agents/ptfe-release-agents/ptfe-aerosol-spray/


I'll bet if you are nice to them they might send you a sample.

Paste floor wax is my favorite release agent. I still have the same can I bought over 40 years ago.

This is a very interesting thread, I had been considering buying a 750. I think I'll wait a bit more.

Used a bunch of Johnson paste wax over the years but these days i use Brownells spray release. Easy to use and works extremely well..

I wouldn't be afraid of the 750.. mine has been very good so far, but I've not loaded a ton on it due to no matches.

took mine apart this morning to take a close look at the primer slide and area.. 1st here are some general photos of the unit

my thoughts... 1st not really happy with the hollow are under the single bolt support. assume it is from the mold process and simply may be needed.. you can see the push pin area used to push it out from the mold. Would prefer to have this a solid piece..  I first checked for overall fit and frankly was impressed.. Zero clearance on either bolt area when the part was bolted up with any of the single bolts. very solid fit 

then the real issue.. the last photo is of the area that broke on APs powder bar support.. No that is not a crack but a casting edge..  the exact angle his broke..... there is also one on the opposite side but it does not have the same angle.. the second issue is the very sharp edge formed at the start of the angle, not good for a stress area. For you S&W 41 users think of your slide  and the angle around the breach face.. common to round the sharp angles off to keep the slide from cracking there.

I'll be smoothing out the casting lines and rounding the sharp edge on mine.. AP maybe you can discuss this with Dillon...

fun stuff

I have my "shopping list" and my "bitch list" prepared for tomorrow's call with Dillon.  I'm not very knowledgeable in casting, but it is obvious that horizontal wall in the attachment point, where break occurred, should have match in thickness of vertical one.  So I agree with Jimmy, that hollow space below should not be there.  On top of that there is an imprint of push pin, which potentially adds to the stress on the part at the removal from the mold.  Break line on my part goes through the imprint.  As I said, I'm not a casting guy.

I'll post update tomorrow.
AP

As an engineer who’s designed stuff like this.  Dillon made some mistakes.  These two surfaces should never be used to clamp a part on to the machine.  If the rear attach point was on the outside face of the inner flange of the press frame then this stress point wouldn’t exist.  The forward two attach point holes would need to be clearance holes but they probably are anyway.  BTW, drilling a hole That big in a web is a big no-no.  As for the flash line in the casting...well, that’s a manufacturing issue.  I also really think that a much better part could be made with a CNC wizard.  With a design suite like Solidworks and it’s CNC programming add-in, this could be CNC machined for not a lot more than what it costs now.  

I made a bet onetime with a design lead that I could have 100 ship sets of a part Made by CNC on the dock for less cost than the tooling to cast the part.  I won the bet.

I'd be tempted to rough up the inside of the void and fill it with JB weld or something similar plus "bed" it in place.

blindshooter wrote:I'd be tempted to rough up the inside of the void and fill it with JB weld or something similar plus "bed" it in place.

I don't think that you will gain much unless the resin is reinforced with something like fiber glass.
The bedding compound is great in compression but may fracture in torsion without the fibers to tie it together.

Just sayin

Talked to Dillon's techy this morning.  He's working from home, connection was terrible, and I had a lot of trouble understanding what he was saying / asking, and so is he.  One thing struck me was his question, after he finally understood what is broken, want caliber I was loading, and if I used aftermarket swagger.  That tells me that issue with this part is known.  

Anyhow, I have replacement parts on the way.  I hope to be able to report back results this coming weekend.

AP

Using an aftermarket swager voids the warranty, as it is claimed that it can break parts.

I Googled around quite a bit last night and could not turn up any other cases of that part being broken. It seems it would have surfaced on the internet by now if it was happening to others as well. Especially on Brian Enos forum.

Hard to say.