55 Degree dovetail cutter, Where from?

Good find Michael. This pic makes it nice and clear.

Edited By Vic on 23/09/2014 09:09:44

The range of (all types of) cutters from Harvey Tool is brilliant, but look justifiably expensive. I don't know of a UK supplier that offers a similar range.

Their site does give a good plain English explanation of cutter angles and how they are specified, the image Vic posted clearly shows the dovetails as included angles, but that is a less common way of expressing dovetails as seen and used by the ME fraternity. As it happens they don't show one for the 55 degrees I need!

Ian P

It's an interesting subject for a photographer so I did a quick google. Seems there's no standard for photographic dovetail mounts. Arca Swiss use 45°, Bogen and Manfrotto use 60°. These are included angles as per the Harvey picture.

Edit: No, I'm not sure they are included angles! How frustrating someone didn't come up with a standard for expressing dovetail angles!

Edited By Vic on 23/09/2014 09:41:57

Vic

My definition of 'photographic equipment' was a bit vague. The actual thing I am interfacing to, is a DJI 'Ronin' stabilised camera mount. It is a beautifully made bit of kit and I think incredibly cheap after having seen and examined one.

I milled a series of little test gauges at different angles in order to check what dovetail angle they used as my original very careful measurements seemed to show different angles for the male and female part (but they proved to be the same)

Ian P

What about cutting the dovetail to the full width required with a 45° cutter then angling the cutter at 10° and taking a cut on both sides to make it 55°?

Apart from the fact that its an extra operation that I would need to do twice on each part, the main reason is that I do not want to ever disturb the swivelling head on my mill. I have it absolutely square in both planes by means of trial and error shimming in places not meant to have shims.

Ian P

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Looks very interesting, Ian.

MichaelG.

Edited By Michael Gilligan on 23/09/2014 11:07:06

You could get a standard 60 degree cutter reground. Should not cost too much or you could regrind it yourself in the lathe.

Not that difficult.

Yes agreed, it is extra work. What mill do you have out of interest?

Well I'm not keen on grinding in the lathe and it would be unlikely I could grip the cutter shank accurately without having a collet of the correct size.

I wonder whether it would be better to start with a 45 rather than a 60 degree cutter as the change in angle is less?

Ian P

Could you set it up and cut the angle in the slot with a slitting saw?

Ian S C

An interesting concept, but how would one machine the bottom of the dovetail so that is flat and continuous into the corners? (in other words after the slitting saw had done its job there would be triangle of metal to remove)

I want to avoid tilting the mill head

Vic, its an Emco Mentor (4 speed head)

Ian P

Use a cutter with a shallower  angle than the dovetail side and you should be able to take out the bottom right into the corner

Edited By Keith Long on 23/09/2014 15:09:42

Can't you just set the work at an angle in the vice, one of the little digital angle boxes will set it to 0.1 degree.

If you use a saw for the sides then small flycutter like I showed above will flatten teh bottom & get into the corners.

Does it even have to be cut from one piece, you could fix two strips with a 55deg angled edge to main part, thats how I did this one

J

Edited By JasonB on 23/09/2014 15:14:03

Well that is basically what I am trying to do! With a cutter of the correct angle its just one operation

Ian P

Ian - I quite agree - but you don't seem to be able to get a cutter with the correct angle so you're looking for a way round. Now you CAN get a cutter with an angle that will get into the corner IF you cut the sides with a slitting saw. Otherwise it might be time to bite the bullet and order the cutter from the USA if it will do the job, or get a standard cutter modified. For one or two off, the fiddly approach might be acceptable. If you're comtemplating a "production run" then the custom cutter wins hands down in time saving alone.

Keith

As you say its a trade off between getting a cutter made or getting the same result with a series of machining operations. In this case I am looking to make six or ten identical parts so the correct cutter is appealing.

Ian P

I'd probably bite the bullet and buy a 55° cutter. Only place I've found is this one, £44 for a one inch:

http://www.mr-tools.co.uk/catalogue/42.php

Sussextools.co.uk sell 55 degree cutters, I have bought from them. Not a problem.

Edited By KWIL on 23/09/2014 17:04:09

I did not find that one when I started looking. I would probably not started this thread if I had!

I presume the price shown on their website does not include VAT but I could not find their T&Cs anywhere.

Actually the Sussex tools that Kwil mention have one that is quite a bit cheaper so tomorrow I will contact both potential suppliers and place an order.

Thanks to all for all the suggestions.

Ian P