DRO for Radial Arm Saw/Chop Saw

[Ted Reischl]

I already use a DRO that I installed on the table saw and really like it for a bunch of reasons.

Most of my crosscut work is done on a RAS. Yes, it does hold it's position. The issue is both accuracy and repeatibility. Right now I eyeball a scale on top of the fence. On a good day I can set it within about .010 of what I want, with a light shining on it. For the most part that is ok. The issue occurs when I need to come back much later (after the stop has been moved) and repeat a cut. Hit or miss at best. That is not the case on the TS with the DRO.

Ok, so now everyone knows WHY I want to mount one on the RAS.

Here is the one I ordered from Amazon:

https://www.amazon.com/dp/B01G4FQKNK/ref=twister_B01G9OF3XO?_encoding=UTF8&th=1

I have mounted similar ones on my mini mill so I understand about alignment, etc.

What I am looking for is any good ideas about mounting it on the RAS, what some of you folks may have done. I hate reinventing the wheel if I do not need to.

BTW, I do not do angle cuts on the RAS by swinging the overarm. It is always in the 90 degree position, so there is no worry about cutting the scale in half.

The RAS is permanently mounted in a bench so I do not use replaceable table boards and all that. The fence is permanently mounted.

If you have done this and have some pics, please share!

Thanks, Ted

[Art Mann]

https://www.amazon.com/dp/B01G4FQKNK/ref=twister_B01G9OF3XO?_encoding=UTF8&th=1

Thanks, Ted

The device you linked to has a maximum travel of 24 inches. That limits the length of material you are going to be able to measure pretty severely. For me, that would not be adequate.

[Brian Holcombe]

These guys sell a setup for this type of thing. http://www.jadawley.com/

[Ted Reischl]

The device you linked to has a maximum travel of 24 inches. That limits the length of material you are going to be able to measure pretty severely. For me, that would not be adequate.

The intended purpose for me is not for long pieces.

I can still use the secondary stop for longer work using the plastic tape measure in the t -track like I always have.

What I have found is smaller pieces usually means better accuracy required. I can still do repeatable cuts out to 8' with the secondary stop.

Currently the fence has T-track with two stops on it. It also has a slot that uses the incra measuring tapes. That is going to stay in place. What I am planning so far on doing is replace the inboard stop to suit the DRO. Right now I am thinking I will mill up a block of aluminum to run in the t track with the usual flip up stop. But it will extend past the back of the fence to carry the sensor for the DRO.

[Ted Reischl]

These guys sell a setup for this type of thing. http://www.jadawley.com/

I bet they would love to sell more of those at those prices!

Seriously, that sort of thing is for someone who does not want to spend the time making their own and money is not an issue.

Definitely a well made system, but it is not what I need.

What I am looking for is mounting methods for what I have purchased. Like I said, I can figure it out myself, but there are probably other folks who have done this before and I am curious to see some of their ideas.

At the simplest level it is pretty easy. Machine a block that runs in t track, make sure it sticks out the back far enough to carry the sensor. Drill a hole to allow locking to the t track. Mount the scale on some blocks behind the fence.

Not much to it, but some of the folks may have neat ways to handle dust, allow adjustment for the scale, etc.

[Roger Feeley]

The device you linked to has a maximum travel of 24 inches. That limits the length of material you are going to be able to measure pretty severely. For me, that would not be adequate.

A fairly simple solution is to mount the DRO so that it measures 4'-6' from the blade. Then keep 2' and a 4' spacers (or 2 two foot ones). It's what I do with a much simpler system.

I have a 36" section of all-thread that's 1/2-20. On that I mounted a shop made flip stop and a Morton Quill Stop. The MQS is normally used on milling machine quills. One rotation of the quill stop is .050" and the stop is graduated in thousandths although I don't use them. Much more useful is the button release built into the side of the quill stop that lets me move it around quickly.

But I digress. I have my flip stop mounted about 2' from the blade and then I have a 2' piece of plywood. I jazzed it up by mounting magnets in my flip stop and magnets in my spacer so they stay together. the magnets have the added virtue of sticking to the end of my tape measure.

[Ted Reischl]

A fairly simple solution is to mount the DRO so that it measures 4'-6' from the blade. Then keep 2' and a 4' spacers (or 2 two foot ones). It's what I do with a much simpler system.

I have a 36" section of all-thread that's 1/2-20. On that I mounted a shop made flip stop and a Morton Quill Stop. The MQS is normally used on milling machine quills. One rotation of the quill stop is .050" and the stop is graduated in thousandths although I don't use them. Much more useful is the button release built into the side of the quill stop that lets me move it around quickly.

But I digress. I have my flip stop mounted about 2' from the blade and then I have a 2' piece of plywood. I jazzed it up by mounting magnets in my flip stop and magnets in my spacer so they stay together. the magnets have the added virtue of sticking to the end of my tape measure.

Thanks Roger. But as I mentioned above I am not concerned with measurements out past about 24 inches. Those will be handled by the outboard stop that already exists. I do not want to be using spacers all the time so that every once in a great while I can use the DRO for longer pieces.

I think a lot of folks are missing what I am asking about. I am NOT trying to figure out how to use a 24 inch DRO to work with lumber longer than 24 inches. What I am asking for is ideas on mounting the hardware, dust prevention, etc.

[Brian Holcombe]

I bet they would love to sell more of those at those prices!

Seriously, that sort of thing is for someone who does not want to spend the time making their own and money is not an issue.

Definitely a well made system, but it is not what I need.

What I am looking for is mounting methods for what I have purchased. Like I said, I can figure it out myself, but there are probably other folks who have done this before and I am curious to see some of their ideas.

At the simplest level it is pretty easy. Machine a block that runs in t track, make sure it sticks out the back far enough to carry the sensor. Drill a hole to allow locking to the t track. Mount the scale on some blocks behind the fence.

Not much to it, but some of the folks may have neat ways to handle dust, allow adjustment for the scale, etc.

You've obviously never shopped for 8' long glass scales :D I saw this and immediately thought the prices weren't bad at all.

[Ted Reischl]

You've obviously never shopped for 8' long glass scales :D I saw this and immediately thought the prices weren't bad at all.

Nope Brian, I have shopped for glass scales. Way back when I designed 4X8 laser cutters for the steel rule die folks.

C'mon, gimme a break. A 4 foot long aluminum extrusion, another 5 inch long aluminum extrusion, a few knobs, screws, washers and they had to drill and tap a couple of holes all for what you think is a great deal at $377????

Have you shopped aluminum extrusions? 8 feet of 1.5X1.5 8020 extrusion for $40. They got maybe $35 in materials. So then have to chop it to length, drill and tap a few holes and that is worth $340??? Like I said, they would love to sell lots more of those systems. Don't get me wrong, I think they have a nice setup, just is not worth what they are asking. BTW, there is no glass scale in their GlideStop system. And the price I quoted above does not have a DRO, etc. Just a sticky backed measuring tape.

[Brian Holcombe]

Good luck with your project.

[Ted Reischl]

Then you know as well as I do how much a DRO with glass scales can cost when they get long. I thought this is pretty modest by comparison and it uses a magnetic tape, so going out beyond 8’ is possible.

Custom heavy extrusions are expensive, they don’t have the same economy of scale as 8020 does.

I keep getting the feeling we are talking about two different things? You keep writing about glass scales and magnetic tape. Their standard 4' glide stop fence does not use either of those, just a sticky backed tape and a magnified hairline. I could not even find a price for their "digital package". I am not going to search further for their "digital package" when their manual package prices start at $377.

But thanks for the information, at least I know I am not building something that I could have purchased for a few bucks more.

[Mike Delyster]

These guys sell a setup for this type of thing. http://www.jadawley.com/

Interesting fence.
Well it may not for everybody I could see in a production environment that it would be a time saver.
Thanks for the link.

[Roger Feeley]

I don't think there is any issue with dust in the DRO. I have a DRO mounted under my router table and it's worked fine for years.

FWIW, I use one spacer and it's no bother at all. My home brew flip stop is 3/4" plywood with two magnets. My 2' spacer is also 3/4" plywood with mating magnets in one end. Works like a champ. For anything longer than 4', I measure.

[Ted Reischl]

Interesting fence.
Well it may not for everybody I could see in a production environment that it would be a time saver.
Thanks for the link.

Absolutely Mike. I would never recommend that a production shop start building tooling it could just buy outright. It doesn't make sense. In a lot of shops if you tell a guy to build a piece of tooling it will wind up costing more than just buying one. Labor, fiddling around building something they are not familiar with, etc, etc.

[Rick Potter]

Ted,

When you get it done, I would appreciate your showing it. I am in the same situation, and could use some inspiration.

[andrew whicker]

I don't think those prices are that bad. Someone took the time to draw it, order it, create the LLC / etc, acquire all the parts, paint it, assemble it.

[Ted Reischl]

I don't think those prices are that bad. Someone took the time to draw it, order it, create the LLC / etc, acquire all the parts, paint it, assemble it.

I was looking for ideas on mounting a DRO to a radial arm saw, not a discussion of whether XYZ company charges too much for a product.

It was recommended as a solution to what I am doing when in fact I stated clearly I had already purchased the DRO I wanted to use and was interested in different ideas for mounting it. Evidently I did not make that clear enough.

I am quite capable of machining up anything I need, I have the tools, experience and time. So the decision was already made to use the DRO I referenced, all that remained was suggestions on how to mount it.

XYZ company can charge whatever they want, and I can think that it is too much to pay. Simple as that.

[Ted Reischl]

Ted,

When you get it done, I would appreciate your showing it. I am in the same situation, and could use some inspiration.

I certainly will Rick. It probably won't be long, I received the notice it shipped today. Also, I found a really old cast U aluminum piece I have had for (no kidding) 45 years. So I got the chunk I wanted cut out of it and squared up the surfaces on the mini mill. Tomorrow I am going to cut the slot to clear the clamping block. There is nothing magical about the stop itself, only a few hundred thousand have been built like it. Only this one is out of aluminum instead of wood. Then I will make the block that slides in the T Track and holds the bracket for the sensor. After that I have to do some measuring and thinking about how I want to maybe give it some protection. Right now a piece of angle aluminum I have in the shop seems to be calling my name.

BTW, I bought the mini mill a little over a year ago. It makes a great drill press but it really shines when it comes to stuff like this. My local scrap yard has a huge building where the public can walk in and buy scrap or new stock.

[Rick Potter]

Since you originally asked about ideas.....My RAS setup has a simple melamine fence going to the left about 4', with a tape on top of it. There is a t-slot milled in the fence face, rather than the top like most (no t-track). A simple 2" wide oak plate with an appropriate hole for a 5/16 T-bolt, and plastic wing nut is the stop.

There is a simple piece of 1/4" masonite tacked and glued to the top of the oak stop. The oak is trimmed to slightly less that the height of the fence, so that the masonite rides on the top where the tape measure is. This eliminates sawdust accumulation. The whole piece is trimmed square with the masonite slider piece so it is direct measure from the slider to the tape.

I also have a carefully trimmed 10" piece of scrap to use to space out for small pieces I do not want to try to hold. A dowel with a crutch tip is my holder.

I also covered the table which is two layers of MDF, with 1/4" waxed masonite with a replaceable masonite insert about 5" wide for a blade insert. It is screwed down out of the blade travel (never moves from 90 degrees), and painted red. This is to remind me where my fingers should never be.

The RAS itself rests on a benchtop With the table and fence about 5" above the bench.. which leaves room for offcuts etc. Since I only need three points for stability, the table of the extension fence is only about 6" deep.

Probably not much there to interest you, but I have not seen a setup like it.

[Mike Delyster]

The setup on my Uni-Point is pretty simple. Like Rick I would all so be interested in seeing what the OP ends up with. A DRO would be handy for repeatability.
411260

[Ted Reischl]

Thanks Rick, Mike.

Here is a shot of my current setup on the RAS:

411261

The DRO and scale for it need to go behind the fence. Right now I am making a new flip stop to run in the t track so that I can mount the reader to the back of the stop. The new one is being made out of aluminum and looks like:

411262

The bright green body is from a single piece of cast aluminum tooling that was U shaped. It is now in the L shape shown above. I am going to mill the opening for the blue in it this morning. Then I will carefully size the blue block to be a nice fit. On the back side of the blue block is where I will mount the bracket for the DRO reader head and then start figuring out how I want to mount the actual scale.

I use a tall fence on the RAS because I have some fixtures that I like to clamp to it.

The dust collection you see in the pic needs to be modified just a tad in the future. A bit lower, maybe an inch at most. I got the design for that DC from Frank Howarth, not sure where he got it from. It is the best thing since sliced bread. Very little dust escapes. Things like that are why I asked for some ideas on here, every now and then someone has come up with something really great.

[Ted Reischl]

Things are moving right along. I got the new flip stop block built (it needed a new one so I could attach the sensor from the DRO unit). Came out pretty decent if I do say so myself. Gotta love that mini mill with the DRO's!

Tomorrow I am going to mount it to the rear of the fence with some small blocks. Nothing fancy, just the bare minimum to make it functional.

Still hoping someone who has done this chimes in with a "If you do THIS it will be so much better" suggestion for the mounting. Other than that, I will take a look at it and start thinking about how I can make sure nothing winds up on top of that scale. Obviously whatever it is needs to be behind the scale so the sensor can move back and forth and the flip stop can flip.

[Rick Potter]

Sounds great.

As always you will get it working fine, but wish you had done a few things differently. Then you will be making the Mk II edition....bigger better and more refined.

That's when I will be ready to swoop down and relieve you of the burden of the original model :cool:.