Protective brass caps for fasteners help manufacturers re-use components and make changes to machine tools.

Rapidcaps-fastener-capsTHE RAPid CAP STORY

In 2013, George and I were sitting in the long, grey conference room with our customer. He was complaining, “The problem is, when I want to make changes to the weld fixture, it’s a real pain because the fasteners are all full of weld spatter. We can’t get at the socket to remove the screw.”

This sounded a bit familiar. Sometimes it takes hearing a thing more than once for it to sink through our thick skulls. At that moment, we realized that this was an issue with most of our customers that did welding to produce their end product. George and I looked at each other. “What if we made something to protect the screws from splatter,” I asked. “Would that make it easier for you to use and re-use our RAPid Tooling Components?

Sure!” he said. “When I was done with a fixture I could re-use the components if I want to… or even to add an adjustment shim if we need to.

George is good at coming up with great designs. He and his team were behind the idea of RAPid Tooling Components back in 2000. So I let him stew on it. I told him that once he got a few made we needed to send them into the real world to be tested.

It didn’t take him long to come up with a design for RAPid Caps.

So we sent some out to our customers to try on their fixtures. The feedback was terrific and orders came in before we were set up to market them. RAPid Caps obviously fill a need in the welding and weld fixture world.

Susan Straley
Queen of Lean Machine Design
Rentapen Inc.


RAPid Caps are made of brass. A round stem presses into the socket of a socket head cap screw and covers the top of the screw leaving a slight gap between the head of the screw and the RAPid cap.

Pop-off-screw-capThe tip of a screw driver is wedged into the gap and pops the cap off.

Adjustments and changes can be made. And the cap can be pressed back into the socket to provide spatter protection again.
RAPid Caps come in inch and metric sizes. Check out Rentapen’s RAPid Caps web page for sizes and ordering instructions.

6 Benefits to using Sub Assemblies in Machine Design

Discover How Sub Assemblies Save a Ton of Time and Money in Machine Design.

Sub Assemblies in machine design are fun and easy and the really help save time and money in a lot of ways.  Once you learn how to use them efficiently you will see all kinds of places that they can be used.  Then, you can be the CAD wizard at your company!

A sub assembly is just a 3D CAD Assembly that is inserted into the Main 3D CAD Assembly in machine design.  If that sentence doesn’t make sense, keep reading and watch the video below to get a good idea of how Sub Assemblies are super tools for Machine Designers.

For example these Jergens Jig Feet along with RAPid Shims and manufactured risers are used several times in a fixture.  As sub-assemblies they save time, and unclutter the assembly drawing.





This configuration of RAPid Blocks and RAPid Shims is used in several places on a weld fixture.  Only the pin changes.




So this configuration, without the pin, is a good candidate for a sub assembly.
It will save engineering time to create it once in a Sub Assembly and then insert the Sub Assembly into the Main Assembly several times.


This goal post is part of a change over fixture.  A change over means that more than one product is welded within this fixture.  To “change over” the fixture to hold a different product, one sub assembly can be removed, and another sub assembly (or cover plate) can be put in its place.

In a fixture with lots of parts, it is easier for the machine assemblers to read the assembly drawing and assemble a machine when the drawing is less cluttered.


1)      The Machine Assemblers will love it!  The drawings are easier to read.  There are less Balloons on the Main Assembly Drawing.

2)      It is easier to job out parts of the fixture to be made by contractors or machine shops.

3)      If sub assemblies are contracted out to be made, more people can be working to create the machine at the same time, moving the machine into production faster.

4)      Faster CAD design because the same sub assembly can be inserted several times into the main assembly.

5)      Assembly model checking time is reduced because each sub assembly only has to be checked once.

6)      The MAIN BOM can contain all the parts for the whole machine, just like always.


It depends on your numbering system.  All parts in a sub assembly get normal part numbers.  Even the sub assembly gets a normal part number.  If a 3/8” jam nut is part 103, you can use part 103 inside a sub assembly and also elsewhere in the main assembly and it won’t be a problem.  The main Bill of Material will reflect the total quantity of parts both inside and outside the sub assembly.  And the Sub Assembly Bill of Material will contain only the quantity of part number 103 used in the Sub Assembly.

We find it helpful to use the words “sub assembly” in the name or description of the sub assemblies.  That way they are easy to identify in the BOMs.  Your company may use a special group of numbers for your sub assemblies.

Now discover how to get the Bill of Material (BOM) to show all the parts but balloon only the parts not in the sub assemblies!  Watch this short video.  (The demonstration is using Pro/E Wildfire 4.0. )

So the instructions for flattening  the Bill of Materials for the purpose of ballooning only those parts not included in the sub assembly is as follows.


  • Select Table from Top Menu
  • Select Repeat Region
  • Select Flat/Rec Item from the pop-up window
  • Select the Bill of Material (Table)
  • Select Default or Flat (to flatten the Bill of Material)
  • OR Select Recursive (to expand the BOM show the parts that are in the Sub Assemblies)
  • Select the sub assemblies in the BOM
  • Click OK or “Done”

Be sure to sign up to receive Education and Updates!  All people who sign up in April 2012 will receive RENTAPEN’s DOWEL HOLE GUIDE.

Give me a Recommendation on Linked in!

View Susan Straley's profile on LinkedIn

Leave a comment below… tell me, do you use sub assemblies?  Why or why not?

‘Til next time…

The Queen

Product Design vs Machine Tooling Design, What’s the Dif?

What are the two main differences between product design and machine tool design?

Right off the bat I think of two main differences between designing a product and designing machine tools.



Product Design Time

When designing a product there may be numerous design reviews, you may spend a whole year or longer between conception to tweaking the design, testing it for market appeal, functionality, safety, costs… the list can go on.  And many of these reviews don’t happen just once.

Then, when the product gets very close to completion, the manufacturing team starts planning for production.  What parts will be assembled at what stations.  And the Manufacturing Engineers and Managers start working on planning the design of the production machines.

Machine Tool Design Time


Once the product is getting close to release for production, there is a rush to get the machines, designed, built, and tested fast.  The time line for a Machine can be as little as 1 month.  Some of the more simple tools are created on the fly as the product moves into production and the need is discovered.


With Machine Tool Designs there may be only one or two design reviews.  There is no need to make it look nice for the consumer, though safety and functionality are part of the design and review process.  The whole machine design process doesn’t require as much time or as much… “going back to the drawing board”.  (For those of you who are too young to have ever seen a drawing board, what I mean is in my experience there isn’t as much re-design occuring in machine tool design as in product design.)


One thing I hear from those who move over to machine tool design from product design is that in machine design the available stock size matters.






With each new manufactured part you need to think about using nice numbers so that the part can be manufactured easily with the least number of surfaces having to be finished.

A machine tool designer is always looking up stock sizes.  And every time the designer has to change the size of a part they have to think about stock sizes and which surfaces will need to be finished.

When a machine designer can avoid finishing a surface, he/she saves build time and material, reducing the costs of the machine.  So we must always check our stock sizes, and try to make the mounting surfaces stock dimensions. This way we avoid having to machine a nice mounting surface if we don’t have to.

When a piece of metal is saw cut, the surface is very rough and may not be square to the other surfaces.  So mounting surfaces need to be stock or finished in most all applications.

Hot Rolled Steel is so rough even as stock, it needs to have all it’s mounting surfaces finished.  We use Hot Rolled Steel for weldments only, and cut a minimum of a 1/8 inch off the stock size to make a nice finished surface for mounting other parts onto.  We still make every effort to consider stock size when creating weld fixture parts.

Two companies that we refer to a lot to find out what stock sizes are available are Central Steel and McMaster Carr.

http://www.centralsteel.com  for cold and hot rolled steel and aluminum and sheet metal.  They have angles, tubes, rounds also.


http://www.mcmaster.com for harder steels or other metals not found in the Central Steel catalog such as A2  and 4140 PH (Pre-hardened).

So Product Design vs Machine Tool Design.  If you have experience in both, what differences have you noticed?

RECEIVE a FREE Quick-reference Tool on Dowel Holes.

Anyone who signs up for “Education and Updates” … in April 2012 ….by filling out the form on the right-hand side of the Rentapen web site will receive in their email Rentapen’s Quick Reference Guide to Tolerances for Dowel holes.  This is a handy item to keep on your desk top.  So sign up today for “Education and Updates”.   We email updates when we issue or new blog or press release (about twice a week).

What Where and How of Metal Shims

What, Where, and How of Shims and Shim Packs

I am excited about our new Free 3D CAD Models ordering service on Rentapen’s web site.  I know I promised to talk more about the simple weld fixture (weld jig), this week,  however I am delaying that because this is (I think) so COOL!!

Our line of tooling components are now even easier to use.   I invite you to play with this new 3d model downloading service.  These files are Free!  Since we are still discovering kinks, be sure to let us know if you find any problems.

The videos I have for you today are about how to use this service.  But there is so much more to learn. These videos aren’t polished, but you will get the idea.

First, I talk about shims and show how they are placed in a real fixture. You might want to turn the volume down a bit, I start in the shop…

I know I go on and on about shims at times. I am a big advocate for shimming in weld fixtures.

With so many variables involved in how much heat will be created during welding and therefore, how much distorting will occur on the product being welded, shims and shim packs are essential. They help the production group set up the fixture before full production begins. So that when the weld jig or fixture goes into full production it is putting out a product that works.

In this next video I  show you how to download a file for a RAPid Block(TM) and a RAPid Riser(TM).

And in THIS video, our team member, Kory, tells you how to get your Pro/E parameters into your STEP file.


I hope you have fun trying out the new 3d models and seeing how you can use them. I’d love to see what you come up with! Didn’t you like playing with legos??

Send images of your designs using RAPid Tooling Components to news@rentapen.com

The Queen of Lean Machine Design


How to Create a Better Weld Fixture, Save Time and Money, Without Leaving Your Chair

Rentapen Inc., located In Waukesha, WI has added a brand new free service to their website.

Rentapen is proudly introducing their 3D CAD Models. The 3D Models will be the new American standard for the Machine Designing Industry. Rentapen’s new 3D models will change how Machine Design Engineers and CAD Drafters design their weld fixtures for the better. The 3D Models will greatly reduce machine design time.

Machine Design Engineers and CAD Drafters from the U.S. will now be able to go on to Rentapen’s website and perform quick and easy steps to make a better weld fixture that will save them time and money without having to leave their chair.

The components are used in fixtures to help locate and hold the product that is being welded or assembled.

3D Models can be altered to meet your needs. For instance, RAPid Blocks™ can be ordered with only holes in one end. In the past, customers would buy the RAPid Block™ and then have to put it in their CNC or take it to another vendor to place a hole in it to hold a locating pin or a rest pad. Now Rentapen does it all. Saving costs, time, and hassles for manufacturers.

All of Rentapen’s RAPid Tooling Components™ are made in the U.S.A. This is in line with Rentapen’s vision as the U.S. Leader in machine design and tooling components.

“We have adopted the RAPid Tooling Components to design and build with because of the flexibility, durability and extreme repeatability that they allow us to have in the areas that require quick accurate dial-in,” said Don, tooling manager at one of Rentapen’s long term customers.

“Rentapen earns their customer’s enthusiasm because we enjoy the opportunity to provide efficiency by design, expertise, and very convenient service,” said Susan Straley, President of Rentapen Inc.

Rentapen is dedicated to reducing costs for manufacturers. And their new free 3D service will greatly help manufacturers continue on their lean journey.

“We are very proud to provide this time and cost reducing service. We invite machine designers to come play with it and let us know what you think!” said Straley.

How to Keep Your Business Alive, Without Spending a Dime

Rentapen Inc., A Weld Tooling Company, Continues To Grow Through Constant Learning

Businesses must enhance a culture of constant learning in order to survive and thrive. For example: Rentapen Inc., located in Waukesha, WI is a machine design company that has emphasized learning in their culture statement. Rentapen has thrived during these poor economic times by embracing their culture to learn more everyday.

According to the article entitled Four Ways to Keep Education Alive and Profitable, by Jay Forte, there are four ways that a business can keep education alive in the workforce that doesn’t cost a dime. (mindflash.com)

First, is mentoring and buddy-up. Rentapen’s employees all have a mentor to go to for inspiration, questions, second opinions, etc. For example, Rentapen’s design engineering team all work together in order to get their customer’s 3D designs done more efficiently. Senior Design Engineer, Chris Doll, is always there to answer any questions or concerns that any of the fellow CAD Drafters might have. Also, Blake Peterson, Design Engineering Manager is there to help manage the team, stay organized with all design work, and follows up with all new and existing customers.

Second, is apprentice or internship. Rentapen is involved with WCTC’s Internship Program, which is an opportunity for companies to hire students for a period of time in order for the students to gain more workforce experience. Last year Rentapen took on two interns. Peter Christiansen, who was Rentapen’s IT Programmer Intern, and Kory Maier, the CAD Drafter Intern.
Both interns were hired as full time employees by the end of 2011.

Third, is “Blogucation.” Rentapen’s President and Queen of Lean Machine, Susan Straley, has created a Blog informing the world on Weld Fixture Design. The Weld Fixture Blog teaches beginning machine designers and CAD drafters about weld fixture design. The Weld Fixture Design Blog also demonstrates how to use Rentapen’s standardized yet versatile RAPid Tooling Components™.

Finally, is a fast-track training program. Rentapen offers many resources for all the different departments in the company, in order for employees to gain more knowledge while they work. For instance: the internet, textbooks, and other team members are all accessible at Rentapen Inc. These resources help Rentapen’s employees learn faster and more efficiently.

Rentapen provides jobs, training, and opportunities for people who work together to help manufacturers reduce costs of tooling to make their products. “It is only with the dedication to efficiency, excellence, and customer service by every team member can we retain our customers and fulfill our mission,” said Straley.

6-Questions RE: Locating Pins in Weld Fixture Design


In weld fixture design we often use the holes in the product for locating the product part in the fixture.  What do you  think designers should ask when considering pinning a hole?

Welded Product Parts With Critical Dimensions Tween the Holes



The location of the hole in one product part can be precisely located in relation to the other product parts it is being welded to.  This is done by using the right design methods.



Major design difficulties can occur if some questions are not addressed before starting the 3D modeling process.

What do you  think designers should ask when considering pinning a hole?

What comes to mind for me is:

1) Is the hole location critical to the other parts it is welded to?  If it isn’t it doesn’t mean I WON’T pin the hole, just that maybe I can use a looser tolerance between the pin and the hole diameters, and I won’t need to use an adjustment shim pack to fine tune the locations of the pin.

2) Will you be able to get the product out of the fixture if you pin the hole?   Or, do you have to remove the pin before you are able to remove the product from the fixture?  We will be going over how to use a straight action clamp in weld fixture design for removing a pin in future blogs.

3) Are there other holes in that same product part that are pinned?  You need to take care here because you need to understand that there will be tolerance issues between the holes.  Yet , two holes makes it easy to locate the part at just the right angle.

4) Will you need to rough locate the part before it is pinned so that it is easier and faster for the pin to find the hole, or the hole to find the pin?

Rough Locator

Pink Rough Locator helps position the Product Part


For example, The product parts are dark gray.  In this picture, the pink round part is a rough locator, along with other locators it gets the product part in close proximity to perfect.  Then the removable purple pin with the help of a straight action clamp moves into place to hold the part in the perfect place while it is being welded.

5) Will you use a shoulder pin that can also act like a rest pad?

Shoulder Pins Can Be used as Rest Pads.


In this picture the left pin is a shoulder pin.  The product plate (in dark gray) rests on the shoulder.  The yellow part underneath it is a metal precision shim pack.



6) How will you prevent weld splatter from making the pin get stuck or welded into the hole?

As you see in the picture, the pins have chamfers on the ends where they protrude through the product plate.  The pins should be harder than the material you are welding.  That makes them last longer in the fixture and reduces the likelihood that the weld splatter will stick to them.  The material of the pin depends on the material you are welding.   In some instances you will need to add guards or shields to protect the pin from the weld splatter.  There is also a protective coating that can be added to protect the pin from the weld splatter sticking to it.

Did I miss some questions?  What else would you consider?

Please share this with a manufacturing engineer or machine builder that you know. We always can learn from the welders, assemblers, machinists and managers who work with our designs every day.

Susan Straley, Queen of Lean Machine Design at Rentapen

Susan Straley
Queen of Lean Machine Design


Do you know someone with some singing or rapping talent? Video tape them singing our Shim King song and we will post it on our shim page and tweet it!