Rupes Backing Plates ARE NOT compatible

**ShawnF350** · 05-25-2016, 08:39 PM

Just to share for those that aren`t aware, the mk1 backing plates DO NOT fit on a MK2.
They are not interchangeable.

I know those that do a washer mod may have seen the arbor turn 90 degrees in the plate. Due to the washer putting the arbor out of the reinforced metal inside the backing plate.
That`s why i was against the mod.
Anyone ever take it back apart and look to see your plate damaged? It tears the plastic recessed key up a bit.
Looks impossible now with the longer keyed arbor

Ray, when will the new mk2 plates be available.

**The Driver** · 05-25-2016, 09:06 PM

Will the Katana plates fit the mkII? If not I guess I`m sticking with my MKI and G21.

**The Guz** · 05-25-2016, 09:06 PM

See Todd`s response here.

Mark II 15

**Todd@RUPES** · 05-26-2016, 12:04 AM

The early run of ES tools had a smaller slot in the backing plate. The later run has the larger slot....

So the ES Backing Plates WILL FIT the MK II, but only the later versions with the larger slot.

**ShawnF350** · 05-26-2016, 07:32 AM

Originally Posted by Todd@RUPES

The early run of ES tools had a smaller slot in the backing plate. The later run has the larger slot....

So the ES Backing Plates WILL FIT the MK II, but only the later versions with the larger slot.

Todd, I bought both the 15 &21 mk1 last year. Both had the small slot.
I purchased a 5" bp too off Autopia in late summer of 15. No big slot on that either.
So how do i go about getting a 5" bp that i know Will fit my mk2 21.

**Todd@RUPES** · 05-26-2016, 08:37 AM

Originally Posted by ShawnF350

Todd, I bought both the 15 &21 mk1 last year. Both had the small slot.
I purchased a 5" bp too off Autopia in late summer of 15. No big slot on that either.
So how do i go about getting a 5" bp that i know Will fit my mk2 21.

Your Mark IIs had the small slot? Did you mean your ES tools?

What color is the trigger on the tools?

As far as getting a newer ES backing plate that has the larger slots, I believe the switch was made in or around July of 2014. If the ES tools or backing plates you purchased were made before July of 2014 than they will small slot. If our distributors have old stock of backing plates, then unfortunately, you will receive the small key. I would give Ray from Autopia a call and have him check out what they have in stock.

**ShawnF350** · 05-26-2016, 08:49 AM

Originally Posted by Todd@RUPES

Your Mark IIs had the small slot? Did you mean your ES tools?

What color is the trigger on the tools?

As far as getting a newer ES backing plate that has the larger slots, I believe the switch was made in or around July of 2014. If the ES tools or backing plates you purchased were made before July of 2014 than they will small slot. If our distributors have old stock of backing plates, then unfortunately, you will receive the small key. I would give Ray from Autopia a call and have him check out what they have in stock.

Sorry for the confusion. I now own mk2s 15&21.

I`ll give Ray a call. But hope there`s a better way to order a proper plate for the newer machines.

**Lonnie** · 05-26-2016, 11:31 AM

ShawnF350:
You are experiencing one of the most infuriating aspects of engineering: designed obsolescence.
Having worked in engineering, I know firsthand how this works and why it`s done. Design "improvements" (AKA changes) to parts happen all the time. Unfortunately, engineers and their counterparts, CAD technicians, will "update" a part for a variety of reasons. Here`s some examples why changes are made:
1) Old Part did not fit new model of existing or old machine, so it was revised.
2) Machine or Assembly Shop made change to part (IE, engineering on the fly) to make it easier to machine or assemble (BUT NEVER consulted engineering to authorize that department to do so, but does tell the CAD technician to make the change for future part production Or it never gets changed (like GM ignition switches))
3) Increase durability or reduce failure from R&D test run or computer simulation (Finite Element Analysis or Motion Kinematics) (this is why high production parts will fail in x-amount of time, usually the time of the machine warranty, to within a month or cycle of constant use. It is no longer guess work; it`s designed to last JUST that long. Which is why the International Harvester refrigerator from 1960 inherited from grandpa out in your garage is still running, and why your new refrigerator in your kitchen from Sears will die in 3-5 years).
4) Materials are no longer available (like a cast iron part or pattern that was thrown out because it was not used or sold in the last three years and hence, not profitable to inventory or stock.)

We (CAD technicians) were always told to research the part change (engineering change) and determine if it was backwards compatible on old machines/equipment. Guess how often that happened when deadlines and department efficiency ratings came into play?? Most times a new part number was taken out to avoid doing this "research". Now you know why you may have an old machine and the owner`s manual has a list of replacement parts that when you call customer service with that old part number, it has been replaced by a new part number. So the old part was a machined cast iron part; new part is a machined weldment (or cast modern plastic) part that looks completely "different" than the part you are replacing. We even had to write on hand drawings (or type on CAD drawings ) in big BOLD RED lettering:
OBSOLETE PART
IFU PART No. XXXXXX-XXX
Date: 25 MAY 16 By: Your Initials

The IFU stood for "In Future Use". We used to joke that it really meant that the engineer or designer admits "I F***ed Up". We laugh about it to this day.

OK, so this engineering experience is really "more than you wanted to know", but it does give insight what happens to parts, why parts change, and why you may have a different part number for an old part.