The Making of a Prototype

[sergizmo]

lots of pics!

Hi everyone,

I’m going to show you the steps it took to create my latest prototype, an aluminum MOI/mallet model with adjustable weighting. I haven’t decided on a name, so it’s SD-M for now (Serge Deschamps Mallet).

WARNING; THIS THREAD IS L-O-N-G

The first step is design. There are two main considerations; what is the putter supposed to accomplish and what is it supposed to look like. I had designed several blade models and wanted to do a mallet. I knew before starting that it was going to be made from aluminum due to low density and easy machining. This would allow me to spread the weight farther out than with a heavier material and would be easy on my smaller machines. The COG would be higher than is usual, typical of my designs. Loft would also be 0 as per my last model. And of course center shafted. I was looking for a fairly high MOI, but wasn’t going to create an ungainly and awkward putter (ex Doc 17) to chase the highest MOI possible. So it would be an MOI putter, but not a “super” MOI putter. It would have an adjustable weighting system, ranging in weight from 340-370 grams. For weights I wanted cylinders, they are simple to make, look clean, and don’t take up much space. Also a “staggered” weight setup could be achieved, helping to fight any cases of chronic pushes or pulls.

As for looks I wanted simplicity and easy alignment on top. It should flow, but not have any unnecessary features that would increase machine time and serve no real purpose. On the bottom it could be more complex, as the player would not see this at address.

With these ideas in consideration, I came up with a general idea in my head. Sometimes I draw a sketch (as with the last model), but in this case I went straight from mental picture to CAD. In CAD the weight is added/remove/redistributed to achieve the desired COG and weight. This is done through inputting the density of the material. The program then tells me weight, COG, and MOI values (among other things!). The look of the putter is further refined if need be. This is a solids CAD package (as opposed to wire-frame) with the ability to rotate the part in any manner of ways as well as change the color of it. So the image on the screen would be a very good representation of what the finished product would look like.

After all was said and done, I came up with what you see below:

[sergizmo]

The second step is determining the machining operations that need to be done and the order in which they will be done. This is referred to in the field of machining as job planning. This is done to ensure that the part can be properly clamped at every stage of the operation and that no clearance issues occur. It is a very, very important step. Stumbling into machining a complex part can cause big problems.

 

The steps in order are;

 

1) Making a blank. (manual)

 

2) Milling the top cavity. (CNC)

 

3) Milling the sight line. (manual operation, done on CNC)

 

4) Milling the weight pockets. (CNC)

 

5) Drilling the holes in the weight pockets for the screw holes. (manual operation, done on CNC)

 

6) Tapping the weight pockets. (Done by hand)

 

7) Milling the large corner radii. (CNC)

 

8) Milling the bottom cavity. (CNC)

 

9) Milling the side drafts on the sole. (manual)

 

10) Drilling the shaft hole. (manual)

 

11) Milling the rear draft on the sole. (manual)

 

12) Finishing, stamping, paint-fill.

 

13) Facing the end of the weight. (lathe)

 

14) Turning the weight to the right diameter. (lathe)

 

15) Drilling the through hole for the screw. (lathe)

 

16) Drilling the counter-bore for the screw. (lathe)

 

17) Turning the chamfer. (lathe)

 

18) Parting off the weight. (lathe)

 

19) Facing the parted side. (lathe)

 

20) Assembly.

[sergizmo]

The third step is making any fixtures that will be required. As my little vise only opens to 2”, and the putter is 3.5” front to back I had to make a specialized fixture for all the CNC operations. A fixture has two primary functions; locating the part and clamping the part. The fixture was made on the CNC, as this would allow me to locate positions and drill/mill very accurately with the control and readout.

 

I started with a 5” by 1” cross section of aluminum, about 6” long. This would give me the required space for the putter and any locating and clamping parts. The back, front and left side of the plate were milled with a carbide insert cutter. I took extra care to ensure the back and left side surfaces were perpendicular, as the top left corner would be my zero. Four countersunk holes for t-nuts were drilled next. Four flat head Robertson screws hold the plate to the table by way of the t-nuts. Then the fixture is aligned on the table precisely so that when the indicator is moved along the entire back surface the needle stays at zero. The plate is then tightened down and checked again with the indicator. Refer to the first pic below. Here I am indicating the fixture after it has been completed. Every time it is placed back on the machine it is re-indicated. Indicating the fixture ensures that the dowel-pin holes are in the right spot and that the putter is in the correct position (ie. square to the table) when it is run.

 

 

 

For locating purposes three .250” diameter ground dowel pins were used. To locate them I used an edge finder to find the top left corner of the plate. An edge finder’s tip is a .2” diameter (ie. .1” rad) ground cylinder that is attached to the main body of the edge finder with a spring. It is then spun at speed (about 1,500 rpm) and slowly brought into contact with the edge of the plate. When the tip wobbles off center, it is touching the edge. At this point you know that the spindle is exactly .1” from the edge of the part. The axis is then zeroed in the control, brought over .100” until the spindle is in line with the edge, and re-zeroed. This process is done in both the X (left - right) and Y (front-back) axis. When finished, the top left corner becomes the origin, or zero, of the part. The pic below is of the blank being edge found on the X axis, but the same principle applies. Using the readout on the control for X and Y positions, the holes are then drilled.

 

 

 

Next three holes are drilled and tapped for the little brass “feet” (acorn nuts) that the putter sits on. This is to raise the putter slightly as the large corner rads are milled all the way through. In one pic you see four, I changed this to three later, two on top and one on the bottom in the middle. This is to prevent rocking and ensure more even clamping force. After the holes are drilled and tapped the feet are milled slightly. This ensures that the top of the feet are parallel to the top of the table. There is a pic of this below.

 

 

 

Next up comes drilling and tapping holes for the screws and step block hold down that will clamp the putter into place. The screw size is ¼-20. Five screw holes for screws with washers were drilled and one for the step block hold down. I used a step block hold down on the left side because that is where the greatest force would be (from milling the large corner rads) and I could alter it’s position slightly to ensure even clamping.

 

 

 

With that the fixture is finished.

 

 

[sergizmo]

The fourth step is to do any CNC programming. There are two ways of doing this: 1) Importing a CAD drawing into CAM software such as Mastercam, setting parameters for the operation(s) to be done and then have it give you the code. 2) Manually programming the code. As I don’t have a CAM package and since the programs would be fairly simple (This isn’t mould making) I was going with #2.

 

The first thing I do when programming is sketching tool-paths. This is taking a sketch of the cavity/contour/feature to be milled and placing points in CAD. Points are when the cutter changes direction, this is where a new line of code is needed. Below is a pic of the top cavity cutout tool-path drawing. It is a simple 2-D sketch that allows me to plot and verify cutter points. With this sorted out, it is time to program.

 

My machine uses Linux CNC control that employs G and M code typical of Fanuc post, run off of a PC. This (Fanuc post) is by far the most prevalent coding system in CNC today. M codes deal with the spindle (on CW, on CCW, off) tool changes, coolant, optional stops and macros. As my machine doesn’t have a tool changer or coolant pump and the spindle is controlled by a speed control on the machine itself, not the program I don’t use any M codes (I don’t use macros or optional stops either). The G codes are movement codes and parameter codes. I use the following G parameter prep codes at the start of all my programs;

 

G17: X-Y plane.

 

G20: Inch data output

 

G40: Compensation cancel (safety)

 

G80: Canned cycle cancel (safety)

 

G90: Absolute co-ordinates (As opposed to incremental co-ordinates)

 

This initial set of commands ensures that the machine is looking at the information presented to it the same way I am.

 

Then movement commands are used. These are;

 

G00: Rapid traverse. (Used when not cutting, just rapidly moving locations)

 

G01: Linear interpolation. (Used when cutting)

 

G02: Circular interpolation clockwise. (Used for rads, circles)

 

G03: Circular interpolation counter clockwise. (Used for rad/circles)

 

Also used is the F command that specifies feed of the table in inches per minute. It is used after the G01, G02 and G03 commands. I tend to use 1-2 for plunging and 5-6 for linear and circular interpolation. The G00 feed-rate is 24.

 

[sergizmo]

The fifth step is milling a blank. A blank is the material machined to it’s outer dimensions; length, width, height. The blank for the putter is 3.98” by 3.5” by .9”.

 

I start with 4” by 1” 6061-T6 aluminum stock about 3.625” long. There is a pic of the raw stock below before cutting.

 

 

 

The 4” wide stock is first milled to a 3.98” dimension by “cleaning up” one side, flipping the part and milling to final dimension. Then this is turned to a 90* angle with a machinist square in the vise and the 3.625” is brought down to 3.5”, milling both sides. This is done with a single carbide insert fly cutter turning at 2,800 RPM. I take a .015” deep cut per pass. There is a pic of this step below. Now the length and width dimensions are finalized.

 

 

 

The height of the putter is now milled. This is done by attaching the blank to the bed of the mill directly with double-sided grip tape. This is the same tape you use to install your grips. Obviously no solvent is used. ; > ) It is strong enough to hold the blank down firmly while not being so strong that it can’t be removed later. Again the single insert fly cutter is used at 2,800 RPM, .015” deep per pass. The blank is “cleaned up” on one side and then brought to the final .9” dimension on the other. With that the blank is finished. There is a pic of this below, along with a pic of the finished blank.

 

 

 

 

 

This machining process is known as “facing”. Milling the entire face of the blank to a specified dimension

[sergizmo]

The sixth step in this operation is milling the top cavity. This is done on CNC.

 

After the blank has been clamped into the fixture, the top corner is found and zeroed on the X an Y axis. This process is the same as the one detailed in post 2. Pic is below.

 

 

 

Next a 3/8” diameter, two flute carbide end mill is installed. The top of the blank is then found by slowly lowering the cutter with the CNC control (in .001” increments when close) while slowly moving back and forth a leaf of “cigarette” rolling paper until it grabs. As the paper is so thin (.0015”) when it grabs and compresses the top of the part has been found. An old machinist trick. This is the Z zero. After it has been inputted, the head is raised. A pic of this is below.

 

 

 

As the part is loaded, cutter installed and origin found, the program is now brought up. This is done by switching the control from Manual to Automatic and selecting the appropriate code that was programmed earlier. The spindle is turned on to about 1,400 RPM and the program started. The program works by milling out the shape of the cavity at a certain depth, dropping .020” and milling it again. This process repeats until the cavity is finished. Below is an in process pic and a finished pic.

 

 

 

[sergizmo]

The seventh step is milling the sight line. This is done by using manual control in the CNC with the putter still clamped in and located from the previous OP (step 6).

 

The 3/8” tool holder is swapped out for a drill chuck and a 3/32” two flute carbide end mill is clamped in this. The X and Y zeros from the previous OP remain. So the cutter is brought over half the length of the part (X axis) which places it on the center of the putter. The Y zero is the back edge of the part and the length of the line is derived from this. The spindle is cranked up to 2,800 RPM (as fast as it goes) and the cutter is slowly lowered until it touches. This is the Z zero.

 

The line is then milled by using incremental jogging in manual control. Feed is set at 4 inches per minute. The line is milled .005” at a time to a depth of .025”. Below is a pic of in process and a pic of the completed line.

 

 

 

 

[sergizmo]

Step eight is milling out the weight pockets. These consist of two cylinders .64” in diameter and .55” deep. The head of the machine is raised. The part is flipped over so that the bottom of the putter is now facing upwards. The X and Y zero values remain the same and do not need to be edge found again. The ground dowel pins on the fixture ensure that the location remains the same. The chuck is replaced with a 3/8” tool holder and a 3/8” diameter two flute carbide end mill is installed. The height is found with paper as detailed earlier.

 

The correct program is brought up, the spindle set to 1,400 RPM and the program run. The cutter plunges at 1 inch a minute .020”, moves .1325” in the Y and does a full circle (both at 5 in/min). It then returns to center and repeats the process until the pocket is finished. Then it repeats this for the other pocket. Below is an in process pic and a completed pic.

 

 

 

[sergizmo]

The ninth step is drilling holes in the weight pockets that will later be tapped. These will receive screws that will hold in the weights. The screws are 8-32 sized. This is .164” major diameter and 32 threads per inch. The tap drill size for this thread is .136”, which is a #29 drill. The production models will be drilled and tapped larger to accept Heli Coils, which are hardened stainless inserts.

 

The part is left clamped in and the head of the machine is raised. The 3/8” tool holder is replaced with a chuck and the #29 drill is installed. The spindle is turned to about 1,800 RPM and brought to the center of the weight pockets via manual jogging on the CNC control. The holes are than drilled, plunging at 2 inches a minute feed-rate. There is a pic of this below.

 

 

[sergizmo]

The tenth step is tapping the weight pocket holes. This is done by hand. The putter is removed from the fixture and the drilled holes are blown out. The 8-32 tap is installed in a tap wrench and some aluminum cutting fluid is applied into the holes. This will improve the surface finish of the tapped holes and allow me to use less force than if tapping dry. Both holes are now tapped. There is a pic of this below.

 

 

After both holes are tapped they are blown out and an 8-32 screw is used to test the fit.

[sergizmo]

The eleventh step is to mill the two large radii on the back corners of the putter. The radius is 1.375” on both corners. This is done on the CNC in the custom fixture. The radii are done one at a time.

 

The putter is installed in the fixture and the top left corner is found with the edge finder as per previous posts. The 3/8” tool holder and 3/8” diameter two flute carbide end mill are installed. The top as the part is found with paper as was done before. The control is switched to Automatic mode and the program is brought up. The spindle is turned to 1,400 RPM and the program is run. It does repeated circular interpolations, doing a 1/4 circle, raising above the part, moving to the start of the radius, and plunging to the next depth. The program cuts .020” per pass and repeats the process until the corner is finished. The feed-rate is 5 inches per minute. Once one corner is milled, the head is raised, the part is flipped over and the program is run again. The part is not re-edge found as the ground pins ensure precise alignment. There is two pics of this below.

 

 

 

[sergizmo]

Step # 12 is milling out the large bottom cavity. This is the final CNC step. Once again the super-duper custom fixture is used. The putter could be left in after the second radii had been milled and just run from there. The origin would be the same. But I had removed the putter after the radii were milled to take some measurements and check things out. The bottom cavity was milled a day later. So it was re-installed, edge-found, and the top was found with the paper method.

 

This program starts the cutter roughly in the center of the cutout. It plunges. It then moves outward in straight lines. The amount it moves out each time is called step over, and I had written this to be about .150”. For the final “step” the outmost edge of the cutout is milled, including the radius (which is a ½ circle circular interpolation). It plunges .020” per pass, mills the cutout, returns to center, and just repeats the process until the final depth of .525” is achieved. The cutter feeds at 1 inch a minute when plunging and 5 inches a minute when feeding otherwise. There is a lot more force when plunging, so care has to be taken. Below are 3 pics, 2 in process and 1 finished. All CNC milling of the putter is done.

 

 

 

 

[sergizmo]

The 13th step is milling the side drafts on the sole. This is done on my manual mill. The putter is held on an adjustable angle plate with two step-block hold-downs and some two-sided tape. In the future I won’t bother with the step-block hold-downs, the tape is more than enough. The angle plate is squared to the table with a ground machinist square. The plate is then accurately set to the correct angle with angle blocks and then tightened down. This is shown in the pics below.

 

 

 

 

The depth to be milled is calculated with trig. A line is also scribed on the part to verify my math and allow me to go quickly at the start. The draft angle is then milled with the single-insert carbide fly cutter. The cutter RPM is 2,800 and I take .025” deep passes to start, and drop that down to .015” deep passes when the full width of the cutter is in use. When the first side is done I remove the part, replace the tape, and re-clamp the part. The process is then repeated. There are three pics below.

 

 

 

 

[sergizmo]

Step 14 is drilling the shaft hole. This is done on the adjustable angle plate. The plate is set to the correct angle with angle blocks and clamped down as before. The putter is then secured to the plate with two-sided tape, ensuring it is square. The drill chuck is installed and a T sized stub drill (.358”) is used. Pic is below.

 

 

[sergizmo]

Step #15 is to mill the back draft on the putter sole. This is the final milling step. The adjustable angle plate is again used. The angle is set as before and the part is again secured in place with two-sided tape. The process is the same as the side drafts. Below are two pics, one in process and one of the machined putter pre-finishing.

 

 

 

[sergizmo]

Step 16 is sanding, finishing, stamping and paint-fill. The two side edges on the face are rounded on the belt sander as in the pic below. Then the bottom edge of the face is rounded on the belt sander. These rads are then further refined by hand with a fine file and some 220 grit sandpaper.

 

 

All surfaces with the exception of the face and large bottom cavity are then sanded with 100 grit garnet sandpaper (aluminum oxide paper “sticks” to aluminum) followed by 220 grit. This is done on a surface plate to ensure the surfaces remain flat. Pic below.

 

 

At this point the S maple leaf D logo is stamped into the bottom cavity. Then all surfaces are Scotch Brited with fine (burgundy), followed by very fine (grey). The putter is then cleaned off and red paint-fill is applied to the sight line and stampings

[sergizmo]

Now it’s on to the lathe work. I will only be making two 15G weights for my prototype as I like my putters @ 370G. Production models will come with two 5G, two 10G and two 15G weights. The 10G and 15g weights will be brass and the 5G will be aluminum.

 

Step 17 is facing off the end of the brass rod. The tool-post is setup with a simple left-hand cutting tool. The height is set with a dead center in the lathe head (the tool-post is a rocking variety). Then the 3 jaw chuck is installed and some brass rod clamped in. The lathe is turned to about 1,500 RPM and two light passes are used to clean up the end. See pic below

 

[sergizmo]

Step 18 is turning the brass stock to the correct diameter. First the end of the stock needs to be supported. This is done by drilling it with a #2 center drill that is held by a chuck in the tail stock. Then the chuck is replaced by a dead center, the dead center is oiled to reduce friction and this is inserted into the tapered hole created by the center drill and the tail stock is locked down.

 

Now the material is turned down, by the same left handed cutter as was used before. I only had some larger brass stock (1” diameter) and it needed to be .62” in diameter but I didn’t want to wait. In the future I’ll use some 5/8” diameter stock and slightly re-design the weights to be .615” in diameter and a bit longer. This will save me a bunch of time. The speed is the same as facing, and the material is turned down to the correct diameter. I made sure I turned down enough material for two weights, taking into account the parting off etc… There is a pic below of this operation.

 

 

[sergizmo]

Step 19 is drilling a hole in the weights for the shaft of the screws to pass through. It is drilled the full length of both weights, as it is a clearance hole. The dead-center is replaced by a drill chuck. The screws are 8-32. The major diameter on the screws is .164”. I used an 11/64 (.172”) drill bit for this hole. The lathe was turned on to about 1,800 RPM and the hole drilled. There is a pic below.

 

 

[sergizmo]

Step 20 is drilling the counter-bore holes in the weights that will hold the screws at the right depth. The head diameter for 8-32 socket-head cap screws can vary from .262” to .270” (as per the Machinery’s Handbook). So I used a 9/32 drill bit ( .281”) to allow for a bit of clearance. The head height of the screws can vary from .159”-.164”. As I wanted the screws to sit under the top of the weight a bit, the holes would be drilled to about .175” depth on the outside diameter (I would start measuring .175” when the outside of the drill made contact).

 

I turned the RPM to about 1,200 and drilled the c-bore for the first weight. Pic is below

 

 

[sergizmo]

Step 21 is putting a small chamfer on the weight. The tool-post is set so the cutting edge of the tool is at a 45* angle to the weight. A Sharpie is used on the edge to verify when the tool is touching. The RPM is set to 800 and the tool is slowly brought toward the part until it skims the Sharpie mark. It is then fed .020” in to make the chamfer. Pic is below.

 

 

[sergizmo]

Step 22 is parting off the weight from the brass stock. I set up a parting tool parallel to the end of the part with the height at the center. I then brought over the tail-stock with the dead center inserted into the counter-bored hole and the tail-stock was locked down. When parting off it is imperative that; 1) A constant stream of coolant/lubricant is applied. 2) The tool is fed in at a steady rate, never pausing or stopping.

 

Initially I tried it under power (about 600 RPM), applying Safe Tap coolant with one hand and turning the hand wheel with the other. But I was having problems keeping a steady flow of coolant and I must have paused for a bit with the hand-wheel. The tool grabbed the part, ripped it out of the chuck and pushed the tail-stock back. The part bounced off the bench, went about 3 feet in the air and landed off the floor. The damage to the part was all on the left side of the cut, so the weight itself had remained undamaged. I just had to face some material off the stock before counter-boring and parting the second part.

 

After I had changed my boxers, I decided to part it off by hand. I turned the chuck by hand, applying coolant periodically and very slowly turning in the hand-wheel in. It took me about 9 minutes per weight to part off by hand, not too bad. Below is an in process pic near the start and the part coming off after it had been cut through.

 

 

 

 

After the first weight was parted off, I counter-bored, chamfered and parted off the second weight

[sergizmo]

The 23rd step was to lightly face the ends of the weights that had been parted off. I had left about .005” of extra material just for this purpose when parting off. I used the same process as in the initial cleaning up in step 17. Pic of the finished weights.

 

 

[sergizmo]

All that’s left now is assembly. A True Temper straight taper shaft is installed (.355” tip) with 24 hour shafting epoxy. It is cut for a finished length of 33.5”. After this has cured a Golf Pride Dual Durometer grip is installed.

 

And now, after all that hard work, we have a finished prototype. Below are some pics. If you have any questions or comments, feel free.

 

Serge

 

 

 

 

 

 

[sergizmo]

Okay, all done! Post away people (when you're done all that reading!). (cool)

 

Serge

[Riuzzi]

Fantastic thread Serge, thanks so much for sharing it with us! I really enjoyed reading about all of the different steps, and seeing the pics (cool)

 

The putter looks great, has a very nice and clean shape to it. Can't wait to hear how it performs on the short grass!

[jaw2000]

What a great job - thanks for sharing it.

[ebs1]

Thanks a lot serge.

There is much more to making a putter than most know.

 

Let us know when your website is up and running cause I'm looking to BUY!!

[coco]

For starters WOOOOOW! (cool)

Amazing work. Thanks for sharing your craft with us. When you get tired of it let me know.....

Awesome putter!

[ftjoy285]

Very cool thread.

 

 

Only problem is you made the putter backwards!