DRDT2 Dimpler - Page 3

John Courte · #21 07-07-2005, 01:53 PM

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

txaviator · #22 07-07-2005, 03:07 PM

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:

Highflight · #23 07-07-2005, 03:27 PM

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.

jferraro17 · #24 07-07-2005, 03:56 PM

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

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!

Highflight · #25 07-07-2005, 09:09 PM

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.

cobra · #26 07-07-2005, 10:23 PM

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?

rv7boy · #27 07-07-2005, 10:28 PM

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

szicree · #28 07-07-2005, 10:37 PM

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

RudiGreyling · #29 07-07-2005, 11:25 PM

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.

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!!!

PS: I have no affiliation to the DRDT2 guys, I am based in South Africa 1/2 way across the world

take that!

tsneidin · #30 07-08-2005, 07:13 AM

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.

Quote:

Originally Posted by John Courte

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