Renz??? scraper, how to adjust stroke?

I inherited this power scraper which I believe to be a Renz, along with a bunch of other scraping stuff from a friend who passed away a couple of years ago. I didn't know he had it, I wish I had known and asked him to show me how to use it.
I've never done much with a power scraper, some roughing a few times but that's it. I had a really nice Biax at the time I got this one but I almost never used it and have since sold it because I don't need two of them. I kept this one for sentimental reasons, although it's not in great shape, I think it will fit my needs.
Recently I took it out and decided to give it a try. It is variable speed so after some roughing, which went really quickly, I slowed it down for finishing. I have been practicing on a small surface plate, and got it down to just under 20ppi with about 30% contact. I think to get it any better I'll need to shorten the stroke a bit which is about 5/16" right now.
There is a square head rod inside a hole on the front of the scraper. It says + on one side and - on the other but turning this rod only turns the motor and makes the tool reciprocate, it does not change the stroke.
What am I missing here. I know these are pretty rare but I hope someone out there is familiar with this model. Rich, I know you've said you've used Renz scrapers in the past and are not crazy about them, but it's what I got. Any other input is appreciated as well. Thanks.

That hole in front is where a socket wrench slides in and you turn that to adjust stroke. I think Renz was closed but someone took them over. Stefan G has one, but used the Biax in the class we helped me with in Germany a couple of years ago. his PM member name is StefanG

It's an OK machine...a whole lot better then hand scraping or some homemade saber saw contraption...lol

PM me and I can give you his email address.

Rich

Here's the current website.Start | Renz Schabtechnik The whole site's in German. I doubt they have any connections here in the states.

This is just internet regurgitation, but I remember reading that you couldn't adjust the stroke on these. maybe that was just on older or simpler models though.

Really cool that you've got a working one!

On Edit (after letting google translate do it's thing): The base model A10 is a fixed stroke 6mm, the better model A20 adjusts from 0-20mm.

On Google that link translates to English.
Here is what it says.

RENZ electronic scraper A 20 with adjustable stroke
Due to its low weight, the RENZ electronic scraper A20 enables low-fatigue work and can be used everywhere where hand scrapers have been used so far.

The slim design and the work-free view of the scraper blade, enables accurate scraping of dovetails, prisms and vertical surfaces.

The variable stroke length offers optimum settings for pre-scoring, point or finishing shears.

The RENZ electronic scraper A20 is radio-interference-suppressed, insulated and has the CE mark.

Technical specifications

stroke 0-20 mm
Stroke rate adjustable up to max. 1600 strokes / min
overall length 420 mm
diameter Max. 90 mm
mass 3.8 kg
elec. Connection 230 or 110 volts

Call us or send us an E-Mail!

RENZ Schabtechnik
Owner: Andreas Weber
Karl-Göbelstraße 12
76684 Östringen
Phone: +49 (0) 7253-935-36-46
E-Mail: [email protected]

Thanks for the feedback guys, I really appreciate it.
Rich, I've tried turning that pin in the hole as I said but I'll give it another try later tonight. Is there maybe a way to keep the motor from turning when you make the adjustment????
I'll pm you later to get Stefan's email, I'd love to talk to him. I've watched a lot of his youtube videos, he's great. I'm really tied up today, I'll add more later.
Thanks again.

I also think Phil or Machtool in Australia has some. Also his rebuilder friend who teaching scraping down there is the a rep for Renz. That screw turns pretty easy I think....

Hi Derek.

I can confirm what you have is a Renz A 20. With the Fein Motor. I'd assume you are adjusting it in the right spot. And have that female square to hex adaptor?

I've never had that issue of back driving the motor, whilst adjusting the stroke. It normally just takes finger pressure. Given your at about 5/16" - 8mm. That's about where I'd lock them. Its kind of the best average of roughing to finish. Provided your not splitting the atom.

Its possible, its never been adjusted, in which case its gummed up. They aren't that complicated to pull apart. You could try some thing more violent, than the normal adjuster. I meant to measure some of mine today. I think its 17mm A.F. Not a rattle gun, but a judicial tap with a dead blow hammer.

Your semi mid stroke now, so it doesn't matter which way you go.

Regards Phil.

Derek.

Did you notice it also has a ball oiler on the case. If you turn it upside down, on the underside there's a nipple. Wouldn't hurt to give it a shot of lube. You need a Pom- Pom gun.

I also externally lube the shaft where it slides in and out of the bush at the front. Thinking about your problem, if it was me, I'd stand him vertical and run some oil down that adjuster shaft in the head of the gearbox.

Regards Phil.

(Adding on Edit). All I've ever used is Vactra 2 - 68 VG

(2nd Edit.) You can see that oil nipple in your first picture. (DSCN2852) Its about an inch to the right of where the leather strap goes on the round journal at the front.

I messed with the Renz a bit more this evening and got the stroke adjustment working. I think is was just a bit gummed up from sitting for so long. After breaking free initially, it was still a bit stiff, wanting to turn the motor more than anything, but after working it back and forth a few times it loosened right up and works great now.

Thanks very much to all who have responded, I so appreciate the help. I really did not want to foolishly damage this thing by blindly forcing things.

Geir Simonsen, thanks for that link. I had watched that video in the past and actually just rewatched parts of it recently. I guess I had just forgot about Stefan adjusting the stroke, but it showed it perfectly!

Phil, If you have anything else to add, especially as to care and maintenance I'd love to hear from you. I don't have any literature for this, obviously, so stuff like oiling points and correct oil would be great to know more about.

Richard, I've been going through lots of old threads to get some help with power scraping, Thanks so much for all you've contributed. I've also been watching some of Stefan's videos, I think I'm gonna send him an email just to thank him as well.

On edit: I was typing while you added your last post Phil, you read my mind about the oiling thing. Thanks very much!

Derek Smalls said:

Phil, If you have anything else to add, especially as to care and maintenance I'd love to hear from you. I don't have any literature for this, obviously, so stuff like oiling points and correct oil would be great to know more about.

Click to expand...

I'll have a dig around in my old filling cabinets. I recall there's a sales brochure, don't recall any detailed maintenance manual. If I find something, I'll scan it and let you know. Could be mid week before I get a chance, I'm slammed with work.

I'd note: Your machine has been dropped. It has the cracked housing. You see them quite often. In my world thats a $4k power tool. Drop a $39 Aldi / Costco drill, they never break. Drop a Biax / Renz and it will crack some thing. I've been a hard arse on the scraping classes we do down here. "If its not in your hands, it lives on the floor". It takes nothing to trip over a cord, and send a machine flying off a bench. I'm drilled to lay them on the floor, they can't fall any further. (Marko's Law).

Regards Phil.

G'day Derek.

I found the documentation I have. Including a parts drawing and a replacement parts list.

I've scanned them all as PDF's. Tried to attach the relevant maintenance page here, but the file is too large at 694k.

There's about 12 pages in all, how ever many of them are just brochure pages.

I should have read the manual, 30 years ago, when I got my first one. I've been doing it wrong all these years. That's a grease nipple. It just calls for 5cc of bearing grease every 4 - 6 weeks. I've just been oiling mine, but daily. Hasn't seemed to have hurt it.

I'll just type out Verbatim what it mentions as Maintenance.

Lubrication of the tools is effected automatically during running. The tools have large lubricant containers so that in case of continuous operation, only all 4 - 6 weeks approx.
5ccm of ball bearing grease has to be refilled at the grease nipples marked by read by means of a grease gun.

Click to expand...

No specification as to the type of grease other than "ball bearing grease".

I'll private message you my email address, so I can get the scans to you.

Regards Phil.

That's awesome Phil, thanks very much!