RCBS Summit Press Flex (pictures)

[Project355]

I don't own a Summit, but I have been a machinist/mechanic all my life

There is a phenomenon "tolerance stacking"

I think a stand of sorts beside the press with a dial indicator attached accordingly could measure the difference between the slide movement of loaded (no case) vs. unloaded. Not impossible but a bunch of precision inspection tools would be needed...

My reference to the Interrapid (or is it just Inter-Rapid, who cares) may indicate my own experience around machines.

Any tolerance stacking should have been eliminated when I further lowered the die, thus requiring quite a bit of effort to "cam over" the mechanism. At that point, its pretty clear the press was under a decent amount of stress at full stroke. By adding more stress, with sizing, the parts no longer touched. The links sit on studs that have a fairly close fit. I'm not going to take out the small hole gauges and micrometer to see how much. Its a very close fit, and the amount of play to get say... the .060"ish gap shown is just not there. Total stacked tolerance, by my estimation is well under .005".

Measuring the slide movement compared with the bench, or the base, is sort of moot. We know the slide moves less when it has a load attached.

Submitted for your approval.... and I'm not 100 percent on this myself... but here goes. First attach the gauge's base to the base of the press. Bring the gauge up to the top of the column. Operate the column, as the die is already adjusted, and see how much back tilt there is at the top of the column. That one is straight forward. The next test is more tricky.... Attach the base of the gauge to the front of the die platform and with the platform say... an inch from full stroke, get adjust the gauge to touch the back of the column (where its accessible). See if the gauge movement, if any, is the same loaded and unloaded. That way, it can be determined if the platform is flexing against the column.

Personally I think its a bit of both. I think the bearing surface on the column, which essentially is a sleeve, has enough bias, or play, to become elongated under pressure. And I think the joint where the column fits the base has some give as well.

What say ye, MDI?

 

[Project355]

The picture you posted where bottom of die touching top of shell holder while not resizing brass is not factoring "slack" in the press/linkages.

I think you missed what was going on. Of the three images, in each of the last two examples, the top has no slack adjusted for, middle has the die under preload tension, as you can observe by the increased lever stroke. Bottom bottom shows same full stroke but with cartridge case in place.

 

[LiveLife]

Any tolerance stacking should have been eliminated when I further lowered the die ... By adding more stress, with sizing, the parts no longer touched.

... the top has no slack adjusted for, middle has the die under preload tension, as you can observe by the increased lever stroke. Bottom bottom shows same full stroke but with cartridge case in place.

So while resizing a case, you are not able to lower the die further so bottom of die drops to top of shell holder?

 

[jmorris]

It’s a bit easier on other types of presses. Just mount a 1/4” rod on one of the bolts at the base of the press, set the indicator on the top, where the die is and operate it.



You could use a feeler gauge between a bottomed die and shell holder and subsequently measure the gap between the two, again with feeler gauges but that would be the total compliance in all parts vs any specific component.

Most people that think something, doesn’t flex just lack the equipment to accurately test it. I used to test racecar chassis’s for torsional rigidity and would even have to account for fixture compliance is the measurements. The shop owner thought I was full of it when I told him I could flex the 1/2” thick sheet steel topped 4” box tube supported table across its length by .010” with one finger, until I showed him.

 

[Project355]

If you mean, can the die be lowered even further in the die platform, of course it can, but that was never part of why I started this thread.

If, on the other hand, you mean can the handle be lowered to further manipulate the die platform, then the answer is no, the platform is at full stroke.

The reason for this post is to illustrate what I believe is flex in the design, or implementation of the design. That flex makes the press unsuitable, in my estimation, for resizing large cartridge cases. Put another way, I've got the press more than locked up solid when the handle is fully down, and the die has been adjusted far beyond "just touching". Its down anywhere from 1 to 1-1/2 turns past "just touching" and yet, when additional stress is placed upon the press, it fails to touch. It "can" be compensated for, but at what cost? Turning the die down another turn and a half? Three turns total from "just touching? That would be about .214 inches. Brother, there ain't that much slop noplace in this linkage, stacked, or not stacked.

 

[Project355]

It’s a bit easier on other types of presses. Just mount a 1/4” rod on one of the bolts at the base of the press, set the indicator on the top, where the die is and operate it.

View attachment 936424

Yah sho'nuff easypeasy. I'm not one to really like dial indicators, but prefer test indicators, specifically the InterRapid. That was my go-to hole finder, edge finder, center finder, runout finder, you name it in the the shop. They just do such an amazing amount of duty, but your setup does what it needs to do, with no fuss at all.

 

[LiveLife]

The reason for this post is to illustrate what I believe is flex in the design, or implementation of the design. That flex makes the press unsuitable, in my estimation, for resizing large cartridge cases.

I understand what you are saying but one would think that designers/engineers checked and addressed the "press flex" during the testing phase before putting the press out to market.

I still think it's likely from "stacked tolerances" mdi posted but I am open to being proven wrong with data.

 

[Project355]

Well.... You think they were good to go at RCBS. But they have redesigned the press a bit, and I've seen a few reports about base cracking. And they've issued changes to the manual thad pryett much address the issue I am describing which, summed up, say "tighten the die some more". So, soon as a base arrives we'll see. Hell, I needed an excuse to get a cheap magnetic base!

 

[jmorris]

I understand what you are saying but one would think that designers/engineers checked and addressed the "press flex" during the testing phase before putting the press out to market.

If RCBS was diligent at testing vs selling a product they wouldn’t have had the broken primer problems that plagued the pro chuckers when they came out.

They are not alone though, plenty of companies rush products into production without running them through the wringer.

I'm not one to really like dial indicators, but prefer test indicators, specifically the InterRapid.

They work well with better resolution, just don’t have a lot of range, cost more and are more delicate. I keep cheap 1” indicators on the shelf and don’t sweat it and are accurate enough for most reloading tasks.

I might test a fixture with a standard and my .00002” resolution Mahr but beyond that it’s a senseless risk of a very expensive tool. There are some folks that say two thousandths isn’t a big deal, more that would say to tenths of a thousandth is no problem at at even with individual components much less stacked and pure silliness to even bother with a 20 millionths indicator.


The .0005” indicators are more than adequate.



And even the lowly 1” with its pitiful .001” graduations will show you all you need to know.

 

[Project355]

I just like the way tthr head swings and the arm pivots on the IR...

 

[GW Staar]

The "originals", the first released design, had three screws. If you look at the RCBS introductory video for the Summit press, when it was first released as a product, that press has three screws. As far as I can tell, not too long afterward they went to two screws.

I still have the receipt from Sportsman's Warehouse dated Jun 10, 2013. RCBS's video showing the 3 bolts on the base is the only one I can find......I think it was a pre-production press, in the March 25th pre-release video, and the same one was photographed for marketing picture-packs sent to all their resellers. I have never seen one out of RCBS's possession......has any of you? Anyone actually own one? Look at the link below: AccurateShooter.com's video and article done also in June a couple of weeks after I bought mine......the RCBS supplied marketing picture was 3 bolts. Their own machine they videoed, was 2 bolts. Somebody that counted, decided 3 bolts was overkill, obviously.

http://bulletin.accurateshooter.com...ess-works-great-in-the-shop-and-in-the-field/

One thing I just noticed in the video.....that gentleman machined a shell plate holder a little higher than the RCBS one. Why? Because I had to use machinist shims under dies in my R.C. to keep from having to readjust the rings for each press.....he was smarter (and had access to a machine shop.) Too bad RCBS didn't notice that.

If RCBS was diligent at testing vs selling a product they wouldn’t have had the broken primer problems that plagued the pro chuckers when they came out.

They are not alone though, plenty of companies rush products into production without running them through the wringer.

True, True. Doesn't help when the company has a marketing conglomerate master breathing down their necks putting on the pressure.

John Lee himself is the one breathing down necks at Lee, and he knows he can continue development using customer testing. He can get away with that at his bottom tier pricing. RCBS, not so much.

 

[mdi]

"What say ye, MDI?" I say I'm done. I've explained as much as I can about manufacturing tolerances, tolerance stacking and proper methods to measure movement/flex, from a lifelong machinist/mechanic's perspective. While not classified as a machine shop inspector, I have done quite a bit of quality control inspection on machine parts and manufactured assemblies. To properly measure the flex of a Summit I would like to have an inspection surface plate, a base/stand and a dial indicator to measure , but have long since given up precision inspection...

 

[Project355]

Well, this was telling.... I was in Harbor Freight today, not to buy this setup, but for a few air fittings, and thought... hey what the heck. Which is good, because I had a quick look thru boxes _I thought_ some of my old tools were in, and struck out. That's a weekend thing I suppose. Anyway, the setup with magnetic base, and the face of the indicator resting on the screw attaching the cap to the column (not on the crinkle paint).

Handle up:

I tried to adjust the reference on the scale without disturbing things too badly, and I'm not about to spend undue time on this illustration, so that what it looks like: Handle up. I could tap on the dial indicator base, or arm rather, and get the indicator to settle in the same spot every time, so I'm satisfied with this setup. And....

Handle down on a .45acp case



The "flex" is about .060", just short, maybe .057ish. Some were a little less, two were just over .060"

Where's that movement coming from? Dunno. Is there additional movement in the die stage? Dunno, the current setup, minus a segmented flex arm (which I don't own) won't do that setup any way that I can easily imagine. Maybe I'll play with it some more later.

When you pull the handle back up... it returns to within .004 of the same spot I marked on the dial, sometimes overshoots a bit, sometimes undershoots, but say a .004" window of repeatability. This isn't the cheap indicator, because I can simple push on the top of the column and get about the same "play". Tells me the point at which it settles has just a tad of wiggle too.

Without going into the trig, a close approximation would be the length of column from its base to measuring point, very close to 7.5", and from column to midpoint of the die which is 4.5". So using the .060" "wiggle" and applying the ratio, that's about (roughly) .036 "gap" at the shell holder accounted for, or about 1/32 of an inch, more or less.

Did not try the .223 yet. Maybe later on. If not.... this weekend I'm running shop air thru my garage, so I'll be mostly tied up and not at the bench.

 

[Project355]

Two vs three bolts... I see one "shot show" video that shows 3 bolts, and the RCBS introductory video shows three. The catalog shows three (even the one I just got), but like has been said... after that beginning time, looks like two bolts. I gotta see if I can dig up the post that had something about cracking in it.

 

[LiveLife]

Here one thread on the Summit press:

https://www.thehighroad.org/index.php?threads/giving-up-rcbs-summit-press.794721/


And found this post by fguffey - https://www.thehighroad.org/index.php?threads/giving-up-rcbs-summit-press.794721/#post-10124374

"Stubbicatt (OP), I do not use ‘tricks’, I use methods and techniques. If I adjust my die to full length size a case the die contacts the shell holder when the ram is raised. When the die contacts the shell holder there should not be a gap between the bottom of the die and top of the shell holder when sizing a case.

[If] there is a gap between the die and shell holder the case had more resistance to sizing than the press can overcome. In the perfect world we would be using new and or once fired brass when sizing. Problem; when a case is fired and sized over and over the case’s ability to resist sizing increases.

Methods and techniques: When a case has more resistance to sizing than my press can overcome I use a better lube. I use a no-name lube for ‘tuff to size cases. A lube can cut down on the cases ability to resist sizing.

When I want to know when my press fails to size a case I measure the gap between the top of the shell holder and bottom of the die with a feeler gage. I can make it more difficult by removing the die with the size case before lowering the ram. My shell holders have a deck height of .125”. After removing the die with the sized case I measure the protruding case head from the bottom of the die. The case head protrusion should be .125” if the case was returned to minimum length/full length sized.

I have helped reloaders with problems with presses that failed to size cases. One reloader had a gap of .017” between the shell holder and bottom of the die. He gave the die an additional one turn after contact while using an A2 RCBS press. That is something no one else understands. The A2 is a cam over press, meaning he went beyond one complete turn after contact."​

 

[Project355]

From the first post quoted:
"Setup of FL sizing dies is not the same as standard "O" presses. One screws the die in to touch the shell holder then another ¾ of a turn. Of course I didn't know this when I bought the press and struggled immensely to figure this out. Here in the last 2 months I called RCBS and they informed me of this "trick" to get it to set back shoulders on bottleneck cases. This additional depth of the die is to accommodate the slop and tolerances in the linkage. The amount of effort you have to put into the handle when FL sizing is much more than other presses."

I agree with almost all of that, which also correlates to the instruction manual "insert" dated 1/9/14, which supersedes the manual which is apparently from 2012, and has never been changed, showing "adjustment" on the platform with locking screws, and three screws on each side of the base.

The part I disagree with, is the part about "accommodate slip and tolerances in the linkage". There simply is not that much slop in the linkage. Maybe I'm using too fine a word filter, but when the press bends, that's not the linkage. The linkage itself is fairly slop and tolerance free actually.

I'll stand by my opinion that the press is sort flexy, and not suitable for any sort of sustained large case sizing. I don't think I'd try to load up 308's or 30-'06's on it. I think the .223 is pretty much maxing out the sustained capability of the press. All that "strain on the handle" is actually the strain on the press as its die platform, base and column deform under stress.

I still like the press for pistol loading - because its small and doesn't hang over the bench. Good for .223 too I guess. Jeeze I forgot to take pictures of .45acp being sized in the carbide sizer "with lubed cases". Guess what? Hardly and "flex", much smaller gap, much easier to press handle. Of course that was to be expected.

 

[tightgroup tiger]

Where you able to notice or measure the two black linkage arms flexing any under load?

 

[Project355]

Sir, that's a heck of a good question! I like the way you think. That should be a real easy measurement. I can check into that later on today. Thanks for something that my mind overlooked!

 

[jmorris]

Where's that movement coming from? Dunno.

Looks like you are mounted to wood and have the indicator base sitting next to it. If that is correct, I suspect a lot of it is in the wood. Take a square piece of metal (3x3 or what ever your indicator base will sit on) and drill a hole in one corner. Use it as a “washer” between the bolt and ear of the casting, now your indicator will be sitting “on” the base of the press vs beside it.

At this point it doesn’t matter how much the wood compresses or flexes as the indicator mount will move with the base of the press. Leaving any difference in measurement being between the base casting and point of contact of the indicator.

 

[higgite]

Where you able to notice or measure the two black linkage arms flexing any under load?

Sir, that's a heck of a good question! I like the way you think. That should be a real easy measurement. I can check into that later on today. Thanks for something that my mind overlooked!

That's not all you overlooked. Posted 4 days ago:

Just for grins, make a thin horizontal mark on each of the two linkage bolts and measure between them with the handle “cammed over” and the die just touching the shell holder. Then resize a case and make the same measurement. If the linkage arms are flexing enough to cause the gap shown in the pictures, you’ll be able to measure it with a ruler.

Tightgroup tiger, thanks for bringing it up again. I figured he had just blown it off.

 

[jmorris]

That's not all you overlooked. Posted 4 days ago:


Tightgroup tiger, thanks for bringing it up again. I figured he had just blown it off.

I imagine it’s also something folks that make or buy “C” linkages for the Co-ax have and will never think about or measure.

 

[tightgroup tiger]

I would check the two U-shaped arms, I'll bet they are giving because the gap between the shell holder and the base looks fairly consistent, front to back.
Put a block of wood under the top ram and bring it down on the wood and put pressure on it. You should be able to see something flex.
Watch the U-shaped arms to see if they are trying to straighten out.

Edit: not straighten out, kink in.

I brought it up back on post 21, but I must not have explained it very well.

I imagine it’s also something folks that make or buy “C” linkages for the Co-ax have and will never think about or measure.

Without a doubt. They purposely weaken the linkage to gain better access to the shell holder. That's the trade off I guess.

 

[Project355]

Looks like you are mounted to wood and have the indicator base sitting next to it. .

No, its got a gap under it.

What I thought would be easy peasy turns out is harder to access, cant get my caliper in there. Gonna look at it again tonite.

 

[GW Staar]

I think it's interesting that in Ultimatereloader.com 's single station press shootout, the lowly Summit was the press that put out ammo with the best concentricity of all of the reviewed presses, in spite of whatever you or I don't like. How scientific that testing was, I wouldn't know. On mine, I had to loosen the shell holders a bit to center and do well, but then that's true with any single station press....and was a "new feature" of MEC's new venture into metallic case reloading.

Link below, but advance to the part about the Summit is at 32:15 on the time line.

 

[Project355]

I could not hold the rule, the flashlight and take a picture at the same time. Sorry.

In both the relaxed state, and under full tension, the mounting positions of the linkage arms are 3.5" apart. In other words, the arms are not flexing.
The linkage stud OD is .373", while the ID of the linkage arm mounting (or pivot if you will) hole is .376". There are three points of pivot on each side, and the top handle mount has the same OD/ID as the linkage arm. That accounts for another .009" of "take-up". Couple that with the .036"ish calculated gap from the column moving (probably moving in the base) we're up to .045". I think the rest of the gap at the shell holder, while under tension, is due to the fit of the die platform to the column and due to the die platform flexing a bit.

I'm gonna still stick with my premise that the Summit is ok for pistol, small rifle cases only. Not that you can't put larger cases in there and size them, but... its not the best tool of choice for that, and probably more subject to wear (especially that fit of die platform to column). As a second press, set up for seating bullets in rifle cartridges, its probably would excel.