The standards identify four initial rust grades based on visual evaluation as described below and shown in these examples: While different in some minor details, these standards are practically identical. The dominant standards for evaluating rust and mill scale are ISO 8501‐1:2007 (based on the Swedish standard SIS 05 59 00), SSPC Vis 1‐89, and NACE. Widely used standards were developed to visually assess the initial surface conditions and the quality of the required surface preparation relative to the initial steel surface conditions. This installment of our Structural Steel FAQ series will answer How are rust and mill scale evaluated pre ‐ and post ‐ blast? Properly evaluating the surface of structural steel surfaces for coating before and after shot blasting will help balance the cost of preparing, repairing, and monitoring structural steel throughout its impressive lifespan. On how thoroughly this surface has been prepared for painting. As Rosler Metal Finishing’s Structural Steel FAQ series has already established, the life of anti‐corrosion coatings on a steel surface depends to a large extent Application of anti-corrosion paint in a preservation line blasting system. I did think that a facemill (2 inch for example) running at a 1.8 inch stepover would leave a good finish and you would never even feel the tool marks particularly if I used some windex on some 2500 grit paper just to finish off.įlycutter is cheaper though, will try that first and give feedback on both.Surface preparation can account for up to 40 percent of structural steel painting and repainting jobs. (Which I did and it worked really well, but had to shim up all the cam-carriers and was a massive whore to do.) The reason for my skimming off the 0.5mm is that i get the compression ratio i'm chasing (i'm not just saying that will do) which is equivalent to me splitting the gaskets and removing 2 layers. I would happily try the face mill fidia guy, but I think for the cost I will try the fly cutter first, then face mill later. it's interesting to see the difference of opinion.įYI i don't own the BP (i think its a clone knee mill anyway) I have a friend with a big knee mill at a motorcycle shop up north I can go to. I hope to consolidate these posts into a final one when everyone has had their 2 bobs worth. 500" - 60.00" per min feed, weighs more than 10,500 lbs, chatter never a problem.Ī face mill 12" + diameter isn't cheap, but would allow faster machining times because of the multiple cutting faces. This mill has a wide speed/ feed range 18 - 1800 rpm and. Has no effect whatsoever on the rebolted components, much better convex than concave. If you think about this you will see that it will produce a very slight convex on the face of the head which The vertical head is always tilted into the direction of travel so that there is no cut on the other side.I do get some movement as the table travels from one extreme to the other but this is very little. Never a problem, could not see a demarcation line where the second cut started. I have machined some longer than table stroke iron cylinder heads and repositioned head by sliding along the table as the heads are always on parallels. They last a long time before resharpening. Tools need to be kept sharp for good finish, but HSS for aluminium heads and brazed carbide for cast iron. I use a Narex VHU56 boring head as a flycutter - makes it very easy to adjust radius of cut. ![]() I've used a Cincinnati 314 Universal mill for the last 29 years to machine cylinder heads of all types. They have ALL been over the size of the head.Įither way I"m spending money. I just don't see that anyone has done it with a face mill anywhere i have checked and checked. If not, i'll try a fly cutter but i bet it's going to chatter with that 1/2 inch shank. I understand you may see the crossover line on the face mill, but you shouldn't feel it, and the tolerance to it should be almost negligible right? Or I can do 3 or so passes with a good quality 2.5 or 3 inch face mill. (I can run my spindle OK at 1500 rpm which appears to be ok.) I can use a big 200mm home made fly cutter someone who is good at making them will make it for me should I ask. I have a way now to fit up to a 3 inch face mill on my my CNC and remove an insert or two if necissary. (Honest)ĪND I just found a product to suit my machine.įigured I'd ask the same question in a more reasonable way then i did last time. I did scour the forum for the last 2 hrs.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |