Setting a 45 degree angle

[ARC-170]

I need a little advice on how to set up a 45 degree angle. I'm making a V-block and need to tip it 45 degrees to make the cut for the vee. I have a V-block, but it's too big for the vise on my mill. I would normally borrow a 45 degree v-block from work, but that's not possible due to the Plague. So, I'm wondering what other options I have.

OPTIONS:
1. I saw this: https://www.ebay.com/itm/Toolmaker-...484553?hash=item5227a5a1c9:g:Tm4AAOSwPW9dy6NJ and thought it might be a good tool to have. Thoughts?

2. I could use a protractor and and tilting vise and line up the mill cutter and the part so they are 45 degrees. Not sure how accurate I can be with this, though.

3. Use one of those digital angle finders used by woodworkers on table saws. Bot sure if these are accurate enough, though. They are +/- 0.1 degrees.

4. Use a sine plate. I've never used one, but this might be the time to learn.

Thanks!

 

[graham-xrf]

Something like one of these? --> LINK
That was from UK.

Similar looking thing here --> USA LINK
The price looks somewhat out of step!

You can get a single, very accurate 45° angle block reference to set up the tilt of a block in the vise under the milling cutter. search eBay for "angle block". You can get a set of two, as 30°-60°-90° and the other as 45°-45°-90°. They claim 20 arc-seconds accuracy i.e. 20/3600 = 0.0055°. This for about $30.
Ahh..Haa, this looks like it! --> Angle Block 2-Set (USA)

I have been considering one of those square digital level indicators that have accurate sides and stick on magnetically. If you have a tilt-able machine vise, and given there are two decimals on the angle, it may be accurate enough. I am still not sure of those if risking relatively low cost. I want something of decent quality, and I would rather save up for a good one. I know I saw one on YouTube that was featured 2 decimals accuracy, not one.

 

[Mitch Alsup]

I, myself, bought 45º and 30º angle sets. These are like parallels (1/8" wide) but are accurate 45º and 30º wedges. Mine are probably accurate to 0.001,5 for 4". This is better than the adjustable blocks can give.

 

[ErichKeane]

5" Sine bar. If you have gauge blocks, they are absurdly accurate. Otherwise, if you can accurately mill a block within a few thou, they are still super accurate.

ETA: with a 5" sine bar at 45 degrees, it is about 11 thou difference in blocks between 44 degrees 59' and 45( and about the same the other way).

So if you have the ability to mill something within +-10 thou, you can be accurate to the minute.

 

[MikeInOr]

When I made my V blocks I just used a V grove cutter in my mill. For my uses they are plenty accurate... if you need high accuracy this might not be for you.

Or you might consider clamping your V blocks flat and tilting your mill head to 45 to mill them.

 

[benmychree]

No body has asked the question as to how accurate this vee block needs to be, or what use it is to be put. That has a lot of bearing on what extraordinary measures need be taken. I am not very sure that the angles need to be accurate or even equal for most ordinary purposes. If accuracy is necessary, likely the product would need to be heat treated and ground. If I had no means of holding the part, such as an angle vise, I'd think of dropping a corner of the blank in the mill table's tee slot and at each side use two pieces of round bar with cross holes drilled in each end for ready rod to clamp them together alongside of the blank snugly and then securely clamp down on the top edge with strap clamps from one side and possibly provide some means of resisting endwise movement.

 

[graham-xrf]

5" Sine bar. If you have gauge blocks, they are absurdly accurate. Otherwise, if you can accurately mill a block within a few thou, they are still super accurate.

You are absolutely right.
You don't even need the gauge blocks. If you can knock up a block to a thousandth or two, maybe rub it down a bit for the last smidgen on abrasive paper, and use a micrometer. Maybe a caliper would be enough. Make a "use once" substitute for a gauge block.

 

[bill stupak]

Make a "use once" substitute for a gauge block

Or use an adjustable parallel

 

[Tozguy]

Do you have a combination square?, just remove the rule from the clamp and you have a 45 deg gauge.

 

[Winegrower]

The digital angle gauges (I bought one) are really kind of toys for metal working. It's OK for woodworking, and I use it to set table saw blade tilt, for example, but it would not be usable even for picture frame mitering, if you have any sense of perfection.

They are somewhat handy if the two surfaces you are referencing are not level to earth and/or in direct proximity, which happens for me once a year or so.