Sunday, March 17, 2019
The following information was gathered during the construction of the Gold King 5-Stamp Mill stamp guides.
I have already completed an article #42 on “Types of Stamp Mill Guides” used on the stamp mill. There are two styles, a wood style and steel with variations of each guide.
GOLD KING VISITS
The picture below shows the Gold King 5-Stamp Mill in Jerome, AZ that is being restored. We had to use all new timbers including guides.
Determining Guide Spacing The original guides could not be saved and we only had parts of the guides left. This meant that we had to start from scratch to build the guides. The first thing we did was to take measurements of the spacing on the cams. We found that the spacing was not the same for all of the cams so we had to custom fabricate the guides.
Guide Templates The next thing we did was to make a template of the guide hole spacings from the above measurements. I used (2) 2” X4” X 53” with a piece of molding strip to make it the same thickness as the 3X12’s. I cut two sizes, 2 7/8” guide holes and 3” for the test stamp. The picture below shows the pieces that will be separated and the “test guide fit.”
Verifying Templates We went to Gold King and installed the “test” guides and the “test” stamp to ensure that we have the proper spacing for the stamps. The pictures below show the fit-up of the test stamp to the test guides. The results were satisfactory!
The critical measurements above is the spacing between the test stamp and the cam lobe. We are looking for about ¼” to 3/8”
PHOENIX WORK ACTIVITIES
Purchased Guide Lumber We brought the “test” guides back to Phoenix to fabricate the guides from the information at the Gold King site. I ordered (2) 3” X 12” X 10’ Douglas Fir timbers that came to $71.00 X 2 = $142 plus tax.
NOTE: From here on in we need to double check all of the measurements associated with the guide timbers. If a slight mistake is made it will make the guides unusable and will have to spend another $142 plus tax to fix the mistake
Transcribe Dimensions We transcribed the measurements from the test guide to the guide timbers below.
Marking the Guide Botling We placed the malleable washer “stars” on the guides and marked their locaitons above. Care must be taken to make sure we do not drill where the stamps will pass through the guides.
Drilling Guide Bolting The holes were drilled that will hold the guides together and anchor them to the cross-members. The all thread was cut small to “temporarily fasten together while drilling the anchor holes and the stamp stems. The final all thread will be about 20” long to allow bolting through the 6” guides and the 12” cross members.
Drilling Stamp Stem Holes with 6” bit This is a critical activity. The 2 7/8” stamp stem holes MUST be drilled perfrecly straight and perpendicular to the guide. If they are off slightly the stamps will not pass through the 12” guides. The holes will be drilled in stages. The first stage we will use the 2 7/8” X 6” forcner bit. We will be able to make (3) passes with this bit. This will take us about 2/3 of the way through the 12” timber, about 8”. That is as far as you can use this bit arrangement.
Special Tools The picture below shows the special tools needed to ensure that we have straight stamp stem holes. The long needle nose pliers is probably the most used item in the tool box. There is very little room between the drill bit and the drill shank when you get towards the end of the drill travel. My last project I did not have this item and it made the job long and painful.
Drilling Stamp Stem Holes with 12” bit Extension This drilling activity is even more critical. The 18” extension makes the drilling activity more sensitive to misalignment. For this activity we will need to check the drill truness more frequently. We not only need to check the guide level, but also the drill bit orientation. The further along we go with the drilling the more sensitive the drill and the guide are affected by misalignment. The two pictures below shows the use of the levels in the process. I was albe to drill the last 4” of guide with one pass of the drill extension.
Job Complete The job took 36-man hours for constructing guides for a 5-stamper. This does not include the manhours for determining the guide configuration of about 20 Mhrs. This is the fourth set of wood guides that I have completed. This includes help from Rick Herrem. The single thing that helps is having a template for the guides. You add much more time, as in the case with the Gold King guides, to do the job if you have to start from scratch. The picture below shows the sawdust that I generated drilling the (10) holes into the two guides. The 30-gallon trash can is about ¾ full of sawdust
Finished Product The picture below shows the finished guides with their markings.
Installation All we have to do now is to install the guides on the Gold King 5-Stamp Mill. I hope they fit!