Pat Marlins Rock Dock "Hack"

I have been a fan of Pat Marlins' products for a long time. A decade ago I went in on his Rock Dock system and it has served me well. The mounting system is flawless, convenient, and well made. I got bases for all my tools. Recently, I added a few tools and needed more bases. I was disappointed to learn that Pat has had to discontinue the Rock Dock - it's not clear to me if that's temporary or permanent.

I have never worked with metal, but did acquire a drill press in the last year. I decided to try to make the bases myself. I learned a lot through this project. Much below will be painfully obvious to the machinists and experienced folks of this good forum. But for those like me, here it is.

First I needed to source a 1/4" thick aluminum square base. McMaster-Carr did not disappoint. Their product number 9246k11 at https://www.mcmaster.com/catalog/127/3978 is an 8"x8" multipurpose 6061 aluminum 1/4" inch thick sheet. It looks like this (sans my markups):

Attachment 288168

The plate is too large, and my first order of business was to learn how to cut aluminum with a bench top table saw. There are blades for "non-ferrous" materials, and the recommended blade for this purpose is an 80 tooth (80T) non-ferrous blade (my saw is 10") and I went with this one from Amazon:

Attachment 288169

The blade cut like a hot knife through butter. That wasn't too hard. Once cut, I noticed the edge was much sharper than the stock, rounded edges. A file took it down until it was fine to touch.


The next issue was marking the plate for the holes of the new tool. There is a type of punch for this purpose called a "transfer punch". You select the size that fits the holes you are trying to mark, insert it in the positioned piece, hit it with a mallet, and the transfer punch transfers a little mark in the center of the hole via the nubbins at the top of the punches. This prevents having to measure or make a template. Very handy, and much easier to get an exact lineup for the holes. This is a set from LittleMachineShop.com, next to my tool centered and positioned on the cut aluminum base:

Attachment 288170

Once marked, I needed to dill the holes. An issue with longer drill bits is that they can wander off the mark when you start. There's a type of punch that can help with this, but I don't have it. Another solution is a drill bit called a "center drill". It's used on lathes, but it's really handy in a press as it is short, stout, and will not wander. I got a set from LittleMachineShop.com, and here it is in my drill press:

Attachment 288171

The starter holes were very nice, and exactly where I wanted them, so I put a drill bit the desired size into the press and went to town:

Attachment 288172

The bit did not wander, and the newly drilled holes were exactly where I needed them. The next issue was how to get a flat-head bolt "inset" into the base, so that the base sat flat in the mount (rather than like a table on four legs). To do this one needs something called either a counterbore, or a countersink. I went with a counter sink because that's what the original Rock Dock bases have. LittleMachineShop was out of stock, so I got a set on Amazon. The bits are triangular:

Attachment 288173

It is in this part of the project where I took a misstep. I eyeballed the bit I needed based on the hole in one of my other bases. I suspect there is a relationship between the holes and the screw head size. I'll have to figure that out before my next base. The other thing that went wrong was I couldn't get a nice, smooth finish on my countersinks. I even used the cutting fluid shown in the picture. And, I eyeballed how deep to go. Rookie move. I should have countersank a hole until it fit my particular bolt exactly the way I wanted, set the depth on the drill press, and drilled 3 other identical holes. I will do that for my next base.

Attachment 288174

If any machinists can tell me how to get a smoother cut, I'd appreciate it. I was over 2500 rpm with the cutting oil. Maybe I was too heavy on the handle? Maybe the aluminum is too hard for the bits? I simply don't know.

Anyway, the finished product was quite to my liking. After installing bolts, it sits flush in my inset mount. I expected I'd need a riser, so the bolts are long. I'll swap those out later.

Attachment 288175

Never let an opportunity to purchase quality tools slip by. Good job on the countersunk holes. If those are getting the job done, NO ONE is going to fault you for trying. We cannot see the result beneath the installed bolt heads anyway. IDK how to do that smoothly either...so am sitting here waiting for the machinists to chime in.

Very nice. I also thought the same thing about the tools and will be eyeing some of them myself. Thanks.

Only thing I would have done differently is to use WD40 as the lube. Your project turned out very well, job well done.

Quote:

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Originally Posted by Rfeustel

I have been a fan of Pat Marlins' products for a long time. A decade ago I went in on his Rock Dock system and it has served me well. The mounting system is flawless, convenient, and well made. I got bases for all my tools. Recently, I added a few tools and needed more bases. I was disappointed to learn that Pat has had to discontinue the Rock Dock - it's not clear to me if that's temporary or permanent.

I have never worked with metal, but did acquire a drill press in the last year. I decided to try to make the bases myself. I learned a lot through this project. Much below will be painfully obvious to the machinists and experienced folks of this good forum. But for those like me, here it is.

First I needed to source a 1/4" thick aluminum square base. McMaster-Carr did not disappoint. Their product number 9246k11 at https://www.mcmaster.com/catalog/127/3978 is an 8"x8" multipurpose 6061 aluminum 1/4" inch thick sheet. It looks like this (sans my markups):

Attachment 288168

The plate is too large, and my first order of business was to learn how to cut aluminum with a bench top table saw. There are blades for "non-ferrous" materials, and the recommended blade for this purpose is an 80 tooth (80T) non-ferrous blade (my saw is 10") and I went with this one from Amazon:

Attachment 288169

The blade cut like a hot knife through butter. That wasn't too hard. Once cut, I noticed the edge was much sharper than the stock, rounded edges. A file took it down until it was fine to touch.


The next issue was marking the plate for the holes of the new tool. There is a type of punch for this purpose called a "transfer punch". You select the size that fits the holes you are trying to mark, insert it in the positioned piece, hit it with a mallet, and the transfer punch transfers a little mark in the center of the hole via the nubbins at the top of the punches. This prevents having to measure or make a template. Very handy, and much easier to get an exact lineup for the holes. This is a set from LittleMachineShop.com, next to my tool centered and positioned on the cut aluminum base:

Attachment 288170

Once marked, I needed to dill the holes. An issue with longer drill bits is that they can wander off the mark when you start. There's a type of punch that can help with this, but I don't have it. Another solution is a drill bit called a "center drill". It's used on lathes, but it's really handy in a press as it is short, stout, and will not wander. I got a set from LittleMachineShop.com, and here it is in my drill press:

Attachment 288171

The starter holes were very nice, and exactly where I wanted them, so I put a drill bit the desired size into the press and went to town:

Attachment 288172

The bit did not wander, and the newly drilled holes were exactly where I needed them. The next issue was how to get a flat-head bolt "inset" into the base, so that the base sat flat in the mount (rather than like a table on four legs). To do this one needs something called either a counterbore, or a countersink. I went with a counter sink because that's what the original Rock Dock bases have. LittleMachineShop was out of stock, so I got a set on Amazon. The bits are triangular:

Attachment 288173

It is in this part of the project where I took a misstep. I eyeballed the bit I needed based on the hole in one of my other bases. I suspect there is a relationship between the holes and the screw head size. I'll have to figure that out before my next base. The other thing that went wrong was I couldn't get a nice, smooth finish on my countersinks. I even used the cutting fluid shown in the picture. And, I eyeballed how deep to go. Rookie move. I should have countersank a hole until it fit my particular bolt exactly the way I wanted, set the depth on the drill press, and drilled 3 other identical holes. I will do that for my next base.

Attachment 288174

If any machinists can tell me how to get a smoother cut, I'd appreciate it. I was over 2500 rpm with the cutting oil. Maybe I was too heavy on the handle? Maybe the aluminum is too hard for the bits? I simply don't know.

Anyway, the finished product was quite to my liking. After installing bolts, it sits flush in my inset mount. I expected I'd need a riser, so the bolts are long. I'll swap those out later.

Attachment 288175

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One thing you need to do to reduce chatter (which is what they call the problem that causes the rough surface) is get your feeds and speeds right. Or at least close. ;) Another is to have the part you're cutting firmly held down. If the part can move even a bit, it will give a rougher surface. You can get clamps that fit in the slots on your drill press table. HF has them. https://www.harborfreight.com/9-inch...ll+press+clamp Or you can make your own in a number of ways. Depending on the countersinks you have, you need to figure the cutting speeds. LMS has a interactive chart for determining your cutting speeds. https://littlemachineshop.com/refere...s.php#Drilling 6061 has a cutting speed of 350-400 surface feet per minute. Plug that into the chart, add the diameter of the cutter, and it tells you the RPM you need. I WAG'ed a 1/2" cutter, got 3056rpm for the cutting speed. I used the Drilling & Reaming chart. You'll get different numbers if you use the Milling chart or Turning chart. You're using a drill press, not a lathe or milling machine, so your feed is however fast & however much pressure you apply to the downfeed on the drill press. Heavy pressure will help, light pressure may let you refine the surface finish a bit.

Chatter, btw, is the cutter flexing while it cuts, or the part flexing or otherwise moving, or both. Sharp tools won't chatter as much, stiff tools won't chatter as much. Before I cut the section of my part that will get threaded tonight, I took a diamond hone to my cutting tool to touch up the edges. That surface looks like a mirror. Slower feeds, shallower depth of cut, and as little stick-out as I could kept the tool from flexing. Using a center drill to start your holes was good practice. Machinists often use something called a spotting drill for the sort of work you were doing. It's shorter, with a very short fluted section, so it's very stiff for it's diameter. Same advantages the center drill has, except it doesn't have the much smaller point of a center drill. Either will work great for that sort of work, but spotting drills are available in all the common drill sizes, so you can spot and drill at the same time. Saves time in a production shop, which is all about through-put. Get metal in, and finished parts out as quickly as possible. You don't have to do that, though if you can it saves time for other fun stuff. Like reloading, shooting... ;)

OTH, if it works and you're happy with it, it's good enough. The aluminum shouldn't be too hard for the bits. You can cut aluminum with mild steel cutters, if you're only going to do it a few times. A good sharp edge helps. High Speed Steel (HSS) tooling works better. It will cut even when the edge is red hot.

I am not a machinist. I'm a student in a machining class. Last night in class I was remaking the plug for a plumb bob that is one of our class projects. I had to figure feeds and speeds for the mild steel I'm using. If I do a good job of it, they'll let me make one in brass, which will require different feeds and speeds, and tooling with different angles would be good, too. Mild steel uses 60-90 SFPM for it's cutting speed for the stuff they buy for us. Tonight, I'll be cutting a thread relief groove in it, and threading. Made one last week, and it worked, but the threads were rough, and the knurl was kinda ugly. This is lathe work, but it could be made on a drill press. Metalworking is fun! It can be useful, too, as you've proven. Add to your shop as you need things to do what you want to do. Just be careful. It can be addictive. I have 4 lathes, 3 milling machines, 3 drill presses, 3 bandsaws... I've spent much of the past several months juggling stuff so I can get all the tools set up and usable. in the mean time, I'm using the machines at school. The lathe I'm using there is a Clausing Colchester 13" lathe. 2700lbs of "small" lathe. The largest lathe I own is a bit over 1000lbs. The smallest is only about 100lbs.

For the countersinks use the slowest speed of your drill press and a heavy feed. Definitely set the depth stop to get consistent size of the countersinks.

As stated above, run your rpm as slow as drill will go. Also, single flute counter sinks give a better finish over a multiple flute CS and can be run at a higher rpm and get desirable results. Single fluters cut more aggressively so watch your down pressure.

Thanks for all the suggestions everyone. I learned a lot through this. Definitely needed new clamps, and now know don’t confuse FPM with RPM. Ugg. So the woodworkers table for drill speeds comports with slower speeds for the countersink in aluminum. The LittleMachineShop calendar results in speeds that the drill I bought from them cannot even come close to except on the largest bits. So on the next base I try slow and heavy.

Quote:

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Originally Posted by Scrounge

One thing you need to do to reduce chatter (which is what they call the problem that causes the rough surface) is get your feeds and speeds right. Or at least close. ;) Another is to have the part you're cutting firmly held down. If the part can move even a bit, it will give a rougher surface. You can get clamps that fit in the slots on your drill press table. HF has them. https://www.harborfreight.com/9-inch...ll+press+clamp Or you can make your own in a number of ways. Depending on the countersinks you have, you need to figure the cutting speeds. LMS has a interactive chart for determining your cutting speeds. https://littlemachineshop.com/refere...s.php#Drilling 6061 has a cutting speed of 350-400 surface feet per minute. Plug that into the chart, add the diameter of the cutter, and it tells you the RPM you need. I WAG'ed a 1/2" cutter, got 3056rpm for the cutting speed. I used the Drilling & Reaming chart. You'll get different numbers if you use the Milling chart or Turning chart. You're using a drill press, not a lathe or milling machine, so your feed is however fast & however much pressure you apply to the downfeed on the drill press. Heavy pressure will help, light pressure may let you refine the surface finish a bit.

Chatter, btw, is the cutter flexing while it cuts, or the part flexing or otherwise moving, or both. Sharp tools won't chatter as much, stiff tools won't chatter as much. Before I cut the section of my part that will get threaded tonight, I took a diamond hone to my cutting tool to touch up the edges. That surface looks like a mirror. Slower feeds, shallower depth of cut, and as little stick-out as I could kept the tool from flexing. Using a center drill to start your holes was good practice. Machinists often use something called a spotting drill for the sort of work you were doing. It's shorter, with a very short fluted section, so it's very stiff for it's diameter. Same advantages the center drill has, except it doesn't have the much smaller point of a center drill. Either will work great for that sort of work, but spotting drills are available in all the common drill sizes, so you can spot and drill at the same time. Saves time in a production shop, which is all about through-put. Get metal in, and finished parts out as quickly as possible. You don't have to do that, though if you can it saves time for other fun stuff. Like reloading, shooting... ;)

OTH, if it works and you're happy with it, it's good enough. The aluminum shouldn't be too hard for the bits. You can cut aluminum with mild steel cutters, if you're only going to do it a few times. A good sharp edge helps. High Speed Steel (HSS) tooling works better. It will cut even when the edge is red hot.

I am not a machinist. I'm a student in a machining class. Last night in class I was remaking the plug for a plumb bob that is one of our class projects. I had to figure feeds and speeds for the mild steel I'm using. If I do a good job of it, they'll let me make one in brass, which will require different feeds and speeds, and tooling with different angles would be good, too. Mild steel uses 60-90 SFPM for it's cutting speed for the stuff they buy for us. Tonight, I'll be cutting a thread relief groove in it, and threading. Made one last week, and it worked, but the threads were rough, and the knurl was kinda ugly. This is lathe work, but it could be made on a drill press. Metalworking is fun! It can be useful, too, as you've proven. Add to your shop as you need things to do what you want to do. Just be careful. It can be addictive. I have 4 lathes, 3 milling machines, 3 drill presses, 3 bandsaws... I've spent much of the past several months juggling stuff so I can get all the tools set up and usable. in the mean time, I'm using the machines at school. The lathe I'm using there is a Clausing Colchester 13" lathe. 2700lbs of "small" lathe. The largest lathe I own is a bit over 1000lbs. The smallest is only about 100lbs.

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Thanks, Scrounge. These are really helpful. Also you are right about the addiction. It’s everything I can do NOT to buy a small lathe right now.

Cool project and I hope you get the brass!

Quote:

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Originally Posted by Rfeustel

Thanks, Scrounge. These are really helpful. Also you are right about the addiction. It’s everything I can do NOT to buy a small lathe right now.

Cool project and I hope you get the brass!

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Go ahead and do it. You know you want to! :) I started with the Harbor Freight 93212 mini-lathe, as that was all I could afford AND lay hands on at the time. Figured I learn how to use it, and then get a bigger one. Didn't have a lot of spare time, and learning how wasn't working so well on my own, but eventually found out that it wasn't the mini-lathe at fault. It was me. Just one of the things you need to be able to do with a lathe requires you to be able to measure your parts. Accurately! You have to develop the touch necessary to get that done, and I didn't know it, and couldn't figure it out on my own. Griped about it to my wife one night, and she said: Bill, you ought to take another class. So I did. Been taking it very part-time, for over 6 years now. They did teach me how to measure accurately. Over the course of a few days, I used my caliper and micrometer and their set of gauge blocks to practice measuring. Gauge blocks (also called Johannsen Blocks or Jo Blocks) are ground and polished to ridiculously fine tolerances. The Grade A set they have are good to .000001" They wring together, i.e., you can put two or more of them together, and they stick to one another, so you can build precision stacks. They're used for setting precision angles, as well. Great for practice measuring until you develop the touch necessary to make accurate measurements. I bought a set of round gauge blocks, 36 pieces instead of the 81piece set they had, so I'd have stuff to practice on at home if I needed it. Once I get the shop set up properly, I'll be buying a full set of Grade B Jo Blocks, too. I'm probably not building rocket parts, so I won't need the Grade A set right off. ;) Though I want one, they're significantly more expensive. If you were to go ahead and buy an inexpensive lathe, I'd get at least a 7x16, or if you can find one of the older American lathes in good condition, that might be the way to go. I found an Atlas TH42, vintage about 1946, and still in good shape on Craigslist for $850 a few years ago. And I found a South Bend Heavy 10L in desperate need of restoration for $950 a couple of years ago. I've been a mechanic of one sort and another for most of the past 50 years, and I'm (VERY) slowly working on restoring it. It's vintage 1941, and was originally shipped to the Ruritan Arsenal in New Jersey that year as a toolroom lathe.

I did finish that plumb bob, and one of my classmates who's learning CNC MasterCam, but otherwise an accomplished machinist, played with it a bit, and commented on how smooth the threads were, and how tightly it fit together. That is only the 3rd set of threads I've cut on the lathe. Instructor said it was nice, too. Though she told me it shouldn't have such a sharp point, as that makes it impossible to measure the length of the part. So I'll be stoning off the point a bit. I plan on engine turning the flats to make it sparkely. Girls love sparkelies! Then I'll give it to my wife, once it is pretty. ;)

Bill

BTW, the modern equivalent of my Heavy 10L is sold by Grizzly.com, who now owns the South Bend Lathe trademark. List price on them is $10K, though they've been for sale recently for as little as $6.5K. They are now made in Taiwan. The MicroMark 7x16 recently came on sale for around $1100, but isn't nearly as capable as the old or new 10L's. Not nearly as expensive, either. I got my 7x10 for $369 in 2008. https://www.grizzly.com/products/sou...d-lathe/sb1007 Back up to $10K plus shipping.

As much as I like In-Line Fabrication system.. I would love to apply Pat Marlins style system to a project that I plan on.. like you stated it is up to a user to make their own as he no longer supplies the basic parts.

The In-Line system is nice. I just didn’t want to swap out all my bases, etc.

https://www.mcmaster.com/zero-flute-countersinks/

I went down your road making up ten 3/8" aluminum plates for use on an in-line fab riser and/or bench mount and had the same hit or miss chatter problem with countersinks. These piloted countersinks cut smooth every time, but you better use your press's depth stop or you will go too deep fast. As you can see mine are a wee bit too deep.

For these 1/4 inch bolts I used the 5/16" countersink.

Quote:

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Originally Posted by oley55

https://www.mcmaster.com/zero-flute-countersinks/

I went down your road making up ten 3/8" aluminum plates for use on an in-line fab riser and/or bench mount and had the same hit or miss chatter problem with countersinks. These piloted countersinks cut smooth every time, but you better use your press's depth stop or you will go too deep fast. As you can see mine are a wee bit too deep.

For these 1/4 inch bolts I used the 5/16" countersink.

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Thank you so much, Oley. Will do!

Quote:

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Originally Posted by kitanis

As much as I like In-Line Fabrication system.. I would love to apply Pat Marlins style system to a project that I plan on.. like you stated it is up to a user to make their own as he no longer supplies the basic parts.

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Not intending to derail this thread, I was of the same opinion (neither quite worked for me). My reloading bench is my work bench and wanted to be able to have a full length clean/flat work area. The option of having routered in cutouts or raised hardware wasn't ideal. So I went the route of modifying the in-line riser to accept ANY flat 3/8" thick material. I drilled new bottom mounting holes so that they are evenly located front to back. Then I drilled all of my 3/8" plates to the same exact pattern. I mounted blind nuts/bolts the length of my work bench that will accept the plates or in-line riser anywhere I need. All holes were counter sunk to allow the bolts to plug the holes and always be where I need them. I have reloading press', trimers, powder dispensers and vises all mounted to the plates. My Wilton Bullet vise is on 3/8" steel plate but still drilled to same pattern.

Fer sure nothing is perfect, but this is working pretty good for me. Perhaps my method will trigger some more better creative juices.

edit added: I bought my 6061 (10) 3/8" aluminum plates cut to size (9"X10.5") from Midwest Steel & Aluminum in Rogers, MN., for $12.90ea. Total cost delivered was $156 (May 2020). Cheaper than I could find locally and I didn't have to cut or end up with a bunch of waste material. https://www.midweststeelsupply.com/s...roductlist.php

Well... I'm a machinist and you have more aptitude than 99.9% of our job applicants.