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DRDT2 Dimpler

mlw450802

Well Known Member
While I have heard nothing but raves about this dimpler, I have a question about the "crispness" of the dimples produced by it. I often see comments along the lines of: "a squeezer doesn't make as sharp a dimple as the one from a C-Frame".
It seems to me the DRDT2 is simply a squeezer with a deep throat for reaching the holes in wing skins etc.

Does it in fact make better dimples that the C-frame types or are the benefits of quietness and ease of use the primary drivers here?

Would All (any of) you DRDT2 drivers out there please chime in on dimple quality?

Please compare it (in your experience) with a dimple from a pneumatic squeezer and a dimple from a C-frame.

Thinking of going that way but wondering if it's worth the money since I already have the other dimpling mechanisms. :confused:

-Thanks,
Mike
 
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I think it makes just as good or better dimplers as the "pound away" method. Every dimle is exactly like the one before--it is extremely consistent. It is my favorite tool by far (though I don't have a pnuematic squeezer) . It makes dimplying a two-handed affair--I don't have to drop and pick up the mallet every time I adjust the skin and it is silent, a factor which cannot be discounted when much of the rest of the process is so noisy!

That said, it is a luxury. I'm glad I spent the money, but with the rising prices of steel (and hence the DRDT2's price), your mileage may vary. I'm sure there are others who say the traditional way of making dimples is more than sufficient. I can't argue with that, I just know that I LOVE it.

good luck.
 
I love mine

I am simply an emp. guy so far, but I'm glad I have this tool vs. the C-frame setup. I dimpled a bit over the weekend at 6:30 AM...wouldn't have felt comfortable making the racket with ta C-frame and hammer.

My caveat: I bought the front end kit and a friend and I fabricated the body. the price of the front end, 20 bucks in raw steel 4-5 hours of a Saturday ( and a 12 pack bribe), and it was a done deal...for nearly the same cost as the C-frame at Avery's

The dimples look good to me--again, as a newbie--they seem to be more a function of the dies versus the tool. My HS has gone together pretty well.

I highly reccomend "the Beast"--as I like to call it--as a DIY project. Mine looks pretty close to the production model, painted vs. powder coat. I can send some pics if you'd like (as long as you promise not to laugh at my welds!)

Joe
-8/8A emp.
 
I've been using the DRDT-2 dimpler on my empennage with good results, IMHO. I back-riveted the rudder stiffeners last weekend. The rivets are so smooth it's difficult to feel them with my fingers. The other rivets are generally nice too. They're not as consistent as back-rivetting, but that's more about my rivetting skill than the dimples. That plus the convenience makes me glad I got the DRDT-2. I can dimple even large skins single-handed. If I had a hammer-style c-frame, I'm sure I would have needed help.

Kev
 
Other Possibility

A little off topic but still relevant I think. If not, let me know and I will delete.

I have looked at the DRDT 2 and IMO it has got to be more consistent than the slamming the rod with the hammer routine. But it is pricey.

Has anyone considered taking a standard C-Frame and attaching a piston (air or hydraulic) to the rod. Attach a foot-pedal to contol it and you have a handsfree, quiet, dimple squeezer.

Maybe it isn't practical but I think it would be a neat option. With the skills on this board I am confident it can be done for a reasonable cost.
 
recommended

I'll chime in:

I did my empennage with a C-frame, then got the DRDT2 and have completed my wings with it. The dimples are fine and so is my arm from not having to swing the deadblow hammer. I would highly recommend it.
 
I know folks have attached air cylinders to their C-frame tools to get a "no hands" dimpler. To me, this is not really needed. I prefer to spend my time actually building the airplane instead of building elaborate tools, but that's just me.

I've not used the other dimpler, but the dimple produced is more a factor of the dimple dies used. I suspect that the DRDT2 will give you a more consistent dimple, as others have suggested, but that's not to say you can't get the same with the C-frame.
 
I currently use the C-frame dimpler with my rivet gun as the hammer force. I put the air pressure down to ~ 15 psi and give a very short brrrp and get very consistent dimples without having to wield a dead blow hammer a zillion times.

It works pretty well but is really unforgiving if you've run out of hands and mis-register a hole. It's quite happy to create one for you. It just sort of happens when speeding along and concentration wanes...

The DRDT2 looked to be a little easier to handle.
As always, looking for easier/better approaches while tempering same with available budget.


-Mike
 
I've got the DRDT-2 and it is great... Built my whole empennage with it and I'm actually looking forward to dimpling my wing skins. One thing I've heard other builders complain about is that sometimes with a C-frame and hammer you can "punch an extra hole" with it if you are not careful. This is pretty much impossible to do with the DRDT. It is by far the easiest way to dimple things (I, too, don't have a pneumatic squeezer). There are many places where I could use the hand squeezer, but the DRDT makes better dimples and is MUCH easier to use and less prone to causing carpal tunnel!
 
DRDT-2 Dimpler

I used a DRDT-2 Dimpler on my RV-10 Emp/Tailcone and bottom wing skins on the QB wings, and loved it. I am working on the QB fuselage and the DRDT-2 is 300 miles away and I really wish I had it here. You can create a new hole even with the DRDT-2 when you get to really moving along. It cut the dimpling time by at lease 50% over using the dead blow hammer, which I know am forced to use.

Russ Daves
RV-10 QB Fuselage
 
The DRDT-2 is great

I got the plans for the frame from Paul Merems at http://www.experimentalaero.com/DRDT-2.htm

I built the frame and then purchased the "front end".
It was a lot of work, but I'm glad I did it.
drdt29tj.jpg
 
I work for Alexander Technical Center at Griffin GA on there tail kit program.
I brought a DRDT1 and started using it there Jan of 2004. We have built over 70 tail kits with it. It has made a big improvement in the quality of the dimples. It takes a noisy two man operation down to a quiet one man operation. The dimples are consistent and less chance of adding extra holes. I am building a RV8A myself. I try to dimple everything I can with it. I and another instructor each just brought a DRDT2 to use away from the center. Get one you will not regret it.

Mike Crowe
 
I am on the old C-frame model and was wondering....aren't there some areas which make it a little tough to pull the handle down on the DRDT2? For instance, when I was dimpling the most forward holes on my elevators, it got kind of tight even with the C-frame. I was wondering how the handle on the other unit kept from being in the way? I suppose just some creative movement of the skin itself, on an as-needed basis?
 
txaviator: Go look at their web page, you could invert the skin and then the handle is free to be pulled down:
http://www.experimentalaero.com/DRDT-2.htm

I also only bought the front end head, while I was in the USA on business trip and brought it back in my luggage. No way I was going to pay for international shipping of the heavy C frame :D

One tip though, make sure you use the same gauge/thickness steel or thicker as per their plans if you want to construct the frame. If you do not the C frame beding moment will not be strong enough and not dimple good. Ask me I know :eek: We tried to cut a corner and used thinner steel which we had in the shop on our first frame. The initial dimples was not good until we redone the frame following plans suggested thickness.;)

I will not trade mine, and everyone that uses mine says they want one as well.

My recommendation...Buy the head, manufacture the frame, you'll have a tool almost the same price as a traditional C-Frame that is much more advanced and easier to work with.

Kind Regards
Rudi
 
Love it!

I love my DRDT-2, and Paul M. (of Experimental Aero) is a class act! I can dimple any time of the day without the racket of the hammer thing. It also makes dimpling a one man operation... one to hold the skin, the other to move the lever.

Close up pictures of a few dimples can be seen here...
http://www.rv7factory.com/log/050701.html

EDIT: I re-read the original post, and in regards to the "crispness" of the dimples... I previously heard a comment from someone who said the crispness of the dimples created by the DRDT-2 is less than those made from the typical c-frame. Looking at some of my work done with a c-frame, I *might* be persuaded to say that yes they are *slightly* less crisp, but only to the degree that can be noticed if you are performing a specific comparison. From 1-2 foot away, I can't tell at all, and I would imagine that any differences in crispness would be well covered with primer/paint. I will gladly trade a tiny bit of crispness for consistency and ease-of-use any day.
 
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Tell me if you think this is nuts or if it's been covered before, but what's to stop me from modding the DRDT-2 (or just fabbing a similar box frame) to have an attach point above the piston in the size and shape of a 2-hole CP-214 type yoke, then use the pneumatic squeezer to drive the dimpler piston? I already have the pneumatic squeezer, and I'm just wondering if there's a way to broaden its usefulness, since it was such an expensive tool.

I'm not a machinist or a welder, or know much about metallurgy, but I'm guessing that strength and rigidity is pretty important here, since it's the frame that's soaking up the load instead of just the piston being impacted.

thanks,
-John
 
John Courte said:
I'm not a machinist or a welder, or know much about metallurgy, but I'm guessing that strength and rigidity is pretty important here, since it's the frame that's soaking up the load instead of just the piston being impacted.
Kinda like this...
US114TCC-98H.jpg


IMHO, you would probobly spend a lot of time and money perfecting the design... much more so than the $325 and month it takes to get a DRDT-2.

PS - The device above is ONLY $1905 from US Tool.

Regards,
 
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[/QUOTE]IMHO, you would probobly spend a lot of time and money perfecting the design... much more so than the $325 and month it takes to get a DRDT-2.

PS - The device above is ONLY $1905 from US Tool.

Regards,[/QUOTE]

Well, that explains that..

So now the trick is to find that big C-yoke for sale on ebay.

I still think I could do it cheaper than 2 grand, but probably more than $325.
But like somebody else mentioned, I'd rather spend the time building the airplane than building new tools...
 
improved dimpler.

Hi,

First time poster - long time listener. I just started an rv-9a. I am a computer professional and as a result suffer from carpal tunnel syndrome. I ordered a set of tools (mostly from yardstore.com) and was playing with the dimpler on some scrap and felt that their had to be a better way - a way that would be easier on my wrists. I had a spare air cylinder and foot pedal so I thought I'd try to improve the dimpler. The pictures below show my first and only try. Works like a charm - so well that I didn't use a single hammer blow on my entire empennage. You can see in the second picture that the unit is lose on the overarm, so that I could move it out of the way if I needed to use a hammer. The pedal obviously would be positioned on the floor during use. I position the skin with both hands and once positioned I press the foot pedal two times. Goes very fast and not a single opps. I can't tell a difference between the ones I did with the hammer and the ones I did with the air cyclinder.

P7060001.jpg

P7060002.jpg


Todd Neidinger
 
Todd,
I really like this idea. What is the bore, stroke & push pressure of your cylinder? Is that just a hefty wood block you have it mounted to? What's a good source for buying the cylinder and pedal?

Thanks,
Scott
 
Yes, inquiring minds want to know..

I thought of something like this at first, but then figured that using the Avery C-frame dimpler as the yoke for a squeezer might put too much stress on the welds, which is why i started thinking about the box-frame DRDT-2.

Does your air cylinder move quickly, like a solenoid, or is it a gradual push? Looks to me like an awesome substitute for hammering.. Gives you an extra hand to maneuver the work. And the pedal is a way cool idea.

-John
 
Avery Tools....

For those of you who have been mentioning using your existing pneumatic squeezer for building a dimpler, check Avery Tools for some ideas???? They have a model that integrates with your existing squeezer. Granted, the depth of the yoke is shallow, but you may get some ideas. It looks like this:

76946fa.jpg
 
There is a fundamental difference between the DRT2 and a typical "hammer" dimpler, and that is that the frame on a hammer dimpler absorbs no stress. All it does is to keep the dies aligned.

On the DRT2, the frame itself takes FULL stress and must be strong enough to keep from spreading apart vertically when the handle is yanked.

I can't tell (for sure) from the photo of the modified hammer dimpler, but if the pneumatic squeezer just "squeezes" down on the dimples, then the frame and/or the squeezer bracket would spread considering how fragile they seem.

Just something to think about.
 
Yanked!?

With the DRDT2 there is no "yanking" involved...

I'm able to get nice dimples with little more effort than a juicer or the pull of a beer tap :D

The legs and welds need to be strong, but IMO, it's due to the weight of the c-frame more than the lever action of the front end.

I guess I'll see in about 10,000 rivets!
 
Pardon my not so clever colloquial choice of the word "yanking".

My simple point is that when you push the lever down on the DRT2, there is a force applied that tries to spread the upper and lower part of the C frame from each other.

With the hammer dimpler, the force is applied directly from the strike of the hammer and the frame itself isn't involved in the operation other than to keep the dimples aligned.

If you were to mount the DRT2 front end on a standard (hammer) dimpler frame, you would see how easy it is for the frame to spread apart as you put some force on the dies.

Picture the operation of each type of dimplers in your head, and the fundamental difference between the two will appear more obvious to you.
That's why simply mounting a pheumatic "pusher" on a standard hammer dimpler might not work as anticipated. Now, mounting a pneumatic device on the DRT2 would be a step in the right direction.
 
A quick observation- the DRDT2 mechanism looks much like a reloading press (used to reload firearm cartridges). I wonder if it is possible to convert one?
 
Pneumatic Dimpler

Vern,
I don't mean to rain on your parade, but I am presently the fifth user of an Avery C-frame which has been modified with the addition of two small air cylinders which replace the hammer.
The air cylinders operate in parallel and are controlled by a puff of air to a small piece of tubing held in the mouth. The tubing is attached to a shuttle valve which is connected to regulated shop air.
It works very well, and so far we see no fatigue cracking of the welds or steel.
I do agree with you that the stresses on the DRDT-2 dimpler frame are different than those imposed on the Avery (or similar) C-frame utilizing a hammer. Our C-frame as modified does impose a spreading load as you describe to the C-frame. So far...so good.
Care must be taken to keep the fingers clear of the dimple dies when the dimpler is in operation. So far we've had no injuries in nearly 10 years of operation. Of course the dimple dies have been changed with each new user.
Don Hull
 
To anybody new to RV building: Save your money and just use the c-frame hammer dimpler. I've built my entire slow build with one and it has always worked just fine. It's probably slower than the lever type, but how much time do we really spend dimpling? Use the money you save to buy the tools that really help.

Steve Zicree
 
Hi Guys,

The forces in the DRDT2 is completely different that a normal C frame. There is also no 'yanking' involved, the lever has a huge leverage effect so it is like pouring beer. Look closely at the lever top, in the picture below that I linked from their web page, you'll see the mechanical advantage and leverage.
DRDT-2-with-text-a.gif


DRDT-2-with-Tank-Skin.jpg



The first frame I build (see my previus post higher up) was not strong enough it bend away without exherting enough force on the dimple.

Below is a picture i 'borrowed' from the DRDT2 Page that shows the stress analyses:

I repeat, buy the head, manufucture the frame yourself, use the correct steel. The Frame is easy to make and they even give you the plans for it. You do not have to buy fancy expensive pnumatic devices or try out experimental setups as described above. It is Simple very effective and will be one of your best tool buys. If you conserned about your investment you will definetly be able to sell it afterwards!!!

miter_mod_vert.gif


PS: I have no affiliation to the DRDT2 guys, I am based in South Africa 1/2 way across the world :D take that!
 
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re: air cyclinder dimpler

The air cyclinder dimpler performs just like a hammer and not like a squeezer. It strikes extremely fast when the pedal is pressed. The c-frame dimpler from yardstore is pretty heavy duty being made out of 1" boiler plate. There is some flex at the end of the stroke when it strikes but nothing that affects the dimples. The cyclinder I have is a 1" stroke attached to a very solid wood block. I would guess it is a one inch bore, but there is nothing to identify this on the cyclinder. I have use max air pressure - around 125 psi.

John Courte said:
Yes, inquiring minds want to know..

I thought of something like this at first, but then figured that using the Avery C-frame dimpler as the yoke for a squeezer might put too much stress on the welds, which is why i started thinking about the box-frame DRDT-2.

Does your air cylinder move quickly, like a solenoid, or is it a gradual push? Looks to me like an awesome substitute for hammering.. Gives you an extra hand to maneuver the work. And the pedal is a way cool idea.

-John
 
I do a lot of dimpling. I work at Alexander Technical center in Griffin GA. on their RV Tail Kit program. http://www.buildtofly.com/ I have used the Avery and Cleaveland C-frame dimplers and the DRDT1 and DRDT2. All those dimplers are available to me. I will only use the DRDTs from http://www.experimentalaero.com/ I believe they do a much better job, especially for the new builder. I would suggest that you might try one out. Paul Merems will be at Oshkosh this year with one. He will be working at the sheet metal workshop. If you are near Griffin or Jackson GA contact me and I will be glad to let you try mine out. Right now the DRDT2 sells for $325 the Avery and Cleaveland sell for $165. I believe for $160 more it will be well worth it. If you are good at welding the front end kit is $137.

I am not connected with Experimental Aero in anyway. I am just a very happy user.

Mike Crowe
 
Love my Dimples

Well, I'm not building an RV, but a 3/4 P-51 from Titan. I have the R2D2 dimpler, and here is my .02.

If I was told that I would have to pay someone competent to help me dimple my whole plane, and I could cut the time down almost in half, and it would only cost me $325, and the work would be consistant each time, I would say, "Let's go!" But for that same $325, I have the R2D2 dimpler, which I can use for the next plane I build. For that price, it is really the best investment in tools I have.
 
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PR

PR-

Hows the T-51 coming. That was the plane that I was going to build but changed my mind.
Where are you at. I know the 2 guys at Altus OK that are building 2 of them.
One is about 1 year from flying and the other 3 or more.

Thanks,
 
It is coming along nicely. Wings all but buttoned up, Finishing up the skins on the forward fuselage, cockpit panel is cut, starting on the aft fuselage, planning to hang the engine this winter! I flipped a coin between an RV 8 and this, but as much as I liked Vans, I wanted to be one of the few Mustangs on the ramp!
 
I am using the DRDT-2. Never used a C-Frame so I can't compare, but I do know that my wife loves to dimple with the -2. If she sees me using it, she will literally kick me off of it so I "can do something else". If I was having to wack those dimples on a C-Frame with a hammer, I am sure she would not be making an offer to help. That alone more than makes up for the higher cost. Besides, the resale value of the dimplers is very good, which lowers the total cost to very little.
 
A little off topic but still relevant I think. If not, let me know and I will delete.

I have looked at the DRDT 2 and IMO it has got to be more consistent than the slamming the rod with the hammer routine. But it is pricey.

Has anyone considered taking a standard C-Frame and attaching a piston (air or hydraulic) to the rod. Attach a foot-pedal to contol it and you have a handsfree, quiet, dimple squeezer.

Maybe it isn't practical but I think it would be a neat option. With the skills on this board I am confident it can be done for a reasonable cost.

Hi,

First time poster - long time listener. I just started an rv-9a. I am a computer professional and as a result suffer from carpal tunnel syndrome. I ordered a set of tools (mostly from yardstore.com) and was playing with the dimpler on some scrap and felt that their had to be a better way - a way that would be easier on my wrists. I had a spare air cylinder and foot pedal so I thought I'd try to improve the dimpler. The pictures below show my first and only try. Works like a charm - so well that I didn't use a single hammer blow on my entire empennage. You can see in the second picture that the unit is lose on the overarm, so that I could move it out of the way if I needed to use a hammer. The pedal obviously would be positioned on the floor during use. I position the skin with both hands and once positioned I press the foot pedal two times. Goes very fast and not a single opps. I can't tell a difference between the ones I did with the hammer and the ones I did with the air cyclinder.

P7060001.jpg

P7060002.jpg


Todd Neidinger

Todd,
Do you still have the photos you mention I've been thinking of the same idea.
Thanks
Rodney
 
I have the DRDT2 and really like it. The one mod that I am going to do make the hand lever articulating, so that it can be adjusted up at times for better clearance of some pieces. I am going to try using an aluminum elbow joint on an old paint roller handle.
 
DRDT-2

Hi All,

Have one of the beasties for sale, a bit heavier than the standard. I was only able to get 1/4" tube so that is what my welder used. A bit heavy but works great. PM me for more info and price.

John H.
 
DRDT-2 VS C-Frame

Can a DRDT-2 make quality dimples like the C-Frame.

Yes if you adjust more preload then you think you may need. The manual for the DRDT-2 says preload is important and to adjust it to give quality dimples. It say's "Typically preload is approximately an additional 1/4 turn beyond step 5". Well, I'm new at this so I adjusted it the 1/4 turn more then step 5 from the instructions. The dimples were concave (under dimpled) outside the actual dimple but being new at this I thought my dimples were as good as they get. Well, not so. To get a quality dimple that looks as good as the c-frame I had to go 3/4 turn past step 5 of the manual. After doing so I can not tell the difference between dimples made from either tool. Now, with different thickness material it may need to be re adjusted. I don't know yet. That's fine, it's easy to adjust and I now know how to recognize a quality dimple.
My tool of choice will be the DRDT-2.

See my log entry at -
http://www.mykitlog.com/users/display_log.php?user=thelynns&project=408&category=0&log=52524&row=6
 
Love the DRDT-2 - but yes you're correct about the 3/4 turn (or at least my experience agrees with yours). The whole point of the 1/2 vs 3/4 turn is to make sure that at the bottom of the stroke, there is enough pressure on the dimple dies to force the steel frame of the DRDT-2 to stretch slightly when taking up the last bit of stroke on the handle. This ensures maximum pressure on the dies, and also guarantees that you can't EXCEED a certain maximum pressure and start "squeezing" the metal to the point of plastic creep. The steel frame itself will spring before the work begins to creep.
 
Ditto

Ditto the importance of the proper preload. If not properly set an under-dimple results with a concave ?valley? surrounding the flush head rather than a crisp transition from flat skin to dimple with a resulting smooth surface. To see the difference try both setups on scrap material then rivet each and compare. Be sure you know the difference before proceeding or you will be disappointed with your initial results. Properly set, however, the tool rocks and allows fast, quiet, consistent results.
 
Got mine last week, works beautifully. Expensive, yes. But it's built like a battleship. It'll outlast me for sure.
 
DRDT-2 RIVET DIMPLER

Anyone know where i might be able to pick up a used DRDT-2?
No one at my airport is selling theirs, even after they have completed their airplanes (I guess its a testament to how much they love this tool!)
 
Thanks a lot Joe! I wasn't even aware there was a classified section on this site. That is great news, will post an ad :)
 
DRDT-2 Purchases..

..can be made directly from the source (Experimental Aero). They are an advertiser on this site and, yes, the DRDT-2 is the bee's knees IMO..
 
DRDT-2 News

Effective 2/1/20

All new DRDT-2?s will be lighter weight and less expensive to ship. This is good news to new customers.

As of January 1, 2020 Both FedEx and UPS lowered their heavy package threshold from 70 lbs down to 50 lbs. Any package over 50 lbs gets a $24 additional fee attached to the regular shipping costs. The shipping weight of the DRDT-2 is approximately 60 lbs. Since shipping costs were now increasing substantially, I began reviewing the 15 year old DRDT-2 design, requirements and analysis. After careful review and building and testing a lighter weight prototype, I am pleased to announce success. This lighter weight design works as well as the heavy weight when dimpling all RV sheet thicknesses from 0.016-0.040". This lighter weight unit looks the same as the heavy weight DRDT-2 except for the reduced thickness of the structural steel frame.

There are several advantages to this lighter weight design.

1. Less expensive to ship than the heavy weight DRDT-2, even without the $24 heavy weight penalty fee.

2. Slightly less expensive frame material which means the DRDT-2 price doesn't have to increase for a few years as other components increase in price.

3. Lighter weight is easier to handle by the customer.

4. FedEx/UPS do not have to take special precautions while handling the lighter unit.

5. After 15 years and over 2,500 units built, my back is feeling the effects of lifting 60 lbs over and over again during the DRDT-2 fabrication.

So if you had the opportunity to use a DRDT-2 in the past (other builders, training centers, USAF, National Guard, Airlines) the one you will receive will be built of a thinner and lighter frame.
 
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