Small hold down clamps for my HV-6 rotary table

[IamNotImportant]

Ah, light goes on. Appreciate the picture.

Unfortunately, I think the teeth don't have the correct shape. The included angle is 60 degrees, but the sides of the triangle are unequal length for a step block. The cutter shown has equal length sides, and no offset. This is not to say that such an insert doesn't exist, but the cutter shown doesn't seem like it would cut the step tooth profile.

i see.. well only two ways to approach it.. try it or not and find another way.. i know that aperture adjustable front sights use these too too, they use a 16tpi cutter which comes out to about 3 moa of sight adjustment on a 30 inch palma barrel.. not sure that you'll understand that.. but that is the best way i can relate it

 

[RJSakowski]

Looking at my two set of blocks and clamps, it appears that the included angle of the the steps is closer to 75º rather than 60º. I wasn't able to find a 75º dovetail cutter but carbide dovetail router bits come in several different angles, among them 76º.

1/2" 14 Dovetail Bit, 1/2" Shank - Grizzly Industrial

Grizzly® cutters feature top-quality carbide - the best available for wood cutting applications. Shaped and sharpened with diamond wheels as fine as 600 grit, these outstanding router bits are constructed with a high-tensile, silver-based brazing material, which offers the utmost in strength and...

www.grizzly.com

I haven't tried carbide router bits for cutting steel but I believe that @JimDawson has done so successfully.

 

[RJSakowski]

 

[WobblyHand]

Looking at my two set of blocks and clamps, it appears that the included angle of the the steps is closer to 75º rather than 60º. I wasn't able to find a 75º dovetail cutter but carbide dovetail router bits come in several different angles, among them 76º.

1/2" 14 Dovetail Bit, 1/2" Shank - Grizzly Industrial

Grizzly® cutters feature top-quality carbide - the best available for wood cutting applications. Shaped and sharpened with diamond wheels as fine as 600 grit, these outstanding router bits are constructed with a high-tensile, silver-based brazing material, which offers the utmost in strength and...

www.grizzly.com

I haven't tried carbide router bits for cutting steel but I believe that @JimDawson has done so successfully.

I can look at mine again. Could have sworn they were 60 degrees. I was going to machine stuff this afternoon, but it seems like I am having a migraine like headache. Why I have this headache, don't know. Hope it goes away by tomorrow.

I will take the dovetail cutter and line it up with the teeth and check for daylight. A 15 degree error should be obvious to pick up that way.

If the angle is closer to 75, I'll investigate those cutters. And, if the angle is 76, well, drat, I will need to redraw the model. The teeth I have are sloped downward more than 7 degrees, closer to 14. But I will remeasure them as well.

 

[RJSakowski]

I can look at mine again. Could have sworn they were 60 degrees. I was going to machine stuff this afternoon, but it seems like I am having a migraine like headache. Why I have this headache, don't know. Hope it goes away by tomorrow.

I will take the dovetail cutter and line it up with the teeth and check for daylight. A 15 degree error should be obvious to pick up that way.

If the angle is closer to 75, I'll investigate those cutters. And, if the angle is 76, well, drat, I will need to redraw the model. The teeth I have are sloped downward more than 7 degrees, closer to 14. But I will remeasure them as well.

I just checked my blocks using a threading insert and the angle does look closer to 60º.

 

[WobblyHand]

I really need to add a camera to my stereo microscope. It has a camera port. Might try adapting an arducam to it. AmScope tries to make fitting your own camera to this microscope as obscure as possible. They are glad to sell you a relatively inferior camera for a lot of cash. I'm not sure if I need a 10x lens like the eyepieces or not. Optics is not my forte. Having a camera attachment of some sort would be handy, even if nothing else, to post here.

But, that aside, I looked at the step block at 20x and I used a fishtail scale. It's not a perfect fit, but it is pretty darned close. I'll attempt to cut out some paper at a 75 degree angle to see if it is a better fit, but I don't really think so. Nope. Not 75, or 76. Very near 60 degrees, which is very convenient for me, since I don't need to buy anything.

Sorry about the optical quality. First photo with a 60 degree fishtail next to the step. Second with a 75 degree angle I printed from CAD.

 

[WobblyHand]

@RJSakowski you gave me a scare there. While it isn't a perfect 60, I think 60 will be close enough.

 

[RJSakowski]

Actually, as long as it angle back, the angle will not be critical. When the step clamp is adjusted, it is placed so the clamp is flat on the clamped surface and then lifted to the next step up to ensure that the clamp isn't just engaging with the edge of the part.

 

[RJSakowski]

I just rechecked the blocks. The new set is indeed 60º. The old set, some 45 years old is greater than 60º, probably closer to 70º. The two sets work interchangeably though.

 

[Alcap]

Here’s how I’m attempting to make the large dove tail for my steady rest . I might try the same with the clamps . Had to make two tools , the one i did for the angle worked ok but kept burning going across the flat though maybe the SFM got too great because I had to extend it , it was hitting the top edge . I slowed it down and rounded the bit I used for the flat seems to be working better but had to quit to help the wife