Leica DM

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apochronaut
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Leica DM

#1 Post by apochronaut » Wed Jul 01, 2020 7:49 pm

Anyone know the large diameter of the head dovetail on a Leica DM IL?

microb
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Re: Leica DM

#2 Post by microb » Wed Jul 01, 2020 8:31 pm

apochronaut wrote:
Wed Jul 01, 2020 7:49 pm
Anyone know the large diameter of the head dovetail on a Leica DM IL?
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apochronaut
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Re: Leica DM

#3 Post by apochronaut » Thu Jul 02, 2020 1:40 am

Thank you for measuring that.

I have a quite substantial 4 objective infinity corrected stand , one incarnation of which was as a Prior Pol microscope. The planachro D.I.N. optics are corrected to the same curves as the first generation AO infinity scopes. The optics are better than average for Chinese planachros . The scope was probably north of 1000.00 ten or fifteen years ago , when an average Chinese made microscope was about 250-300. It's current successor might be something along the lines of a Zeiss Primostar.

I want to put a DM trinocular on it. It has a 25mm telan lens in the head, with a 44mm dovetail but the general shape and dimensions of the original binocular are quite similar to the DM head. The difference is 1mm on each side. Does anybody have good ideas , how best to add the 2mm? My first thought is a band of shimstock around the dovetail, then silver soldered.

Maybe there is something better?

microb
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Re: Leica DM

#4 Post by microb » Thu Jul 02, 2020 2:45 am

apochronaut wrote:
Thu Jul 02, 2020 1:40 am
I want to put a DM trinocular on it. It has a 25mm telan lens in the head, with a 44mm dovetail but the general shape and dimensions of the original binocular are quite similar to the DM head. The difference is 1mm on each side. Does anybody have good ideas , how best to add the 2mm? My first thought is a band of shimstock around the dovetail, then silver soldered.
Is the female dovetail built as a cast like Olympus does? Or is it three set screws but two are cemented? Maybe if you show a picture.

Depth is probably not so much of an issue. But I assume the grub screw can be turned more and take a centering millimetre from that side. You then need a 19 to 20 gauge copper wire the you can make a semi circle with for the other two contact points. A two-third open loop can snap onto the male dovetail of the DMIL head. Maybe you need to stack a couple more smaller gauge 2/3 loops to keep the spacing wire down to push against the two contact point of the female dovetail.

Basically chop some Romex, bend it and center up that DMIL trinocular against the soft copper wire. It shouldn't hurt either dovetails.

PeteM
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Re: Leica DM

#5 Post by PeteM » Thu Jul 02, 2020 6:55 am

The wire suggestion should work - anything with the needed diameter to center. If I read this right, Phil, you need to enlarge the dovetail about 2mm all around? If so, could be 12 gauge wire would be about right? 20 amps building wire (Romex as suggested by microb) is typically 12 gauge. But note the caution below.

I've also used the round plastic handles from cleaning swabs - heating and bending them up to form a circle around the old dovetail.

Another approach - for scopes with two "pads" on the female dovetail part is to make small shims out of brass or aluminum and epoxy them in place. Stays put better and easier to loosen and rotate the head to the back for storage.

A third approach, requiring a lathe, is to make an entire dovetail section, split in half, to fit over the old. Then a bit of glue to keep it in place. This is the most secure of all.

The caution -- I don't know the max dovetail diameter on a DMIL, which may be well what was so kindly measured above. However, a Leica DMLS and DMLB are (I believe) in the 44.7mm range. I'd imagine a Leica DM IL might be the same 44.7mm or so? Just mentioning this, because the measured head says "Leitz" and some Leitz were 42mm (as measured), others 43mm and the Leica DMRB I own around 45.7mm. I also have a notation for some Leitz epi stuff at around 47.3mm.
Last edited by PeteM on Thu Jul 02, 2020 7:16 am, edited 1 time in total.

microb
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Re: Leica DM

#6 Post by microb » Thu Jul 02, 2020 7:15 am

PeteM wrote:
Thu Jul 02, 2020 6:55 am
The wire suggestion should work - anything with the needed diameter to center. If I read this right, Phil, you need to enlarge the dovetail about 2mm all around? If so, could be 12 gauge wire would be about right? 20 amps building wire (Romex as suggested by microb) is typically 12 gauge. But note the caution below.
Did I get the gauge number wrong. I can never remember those values. I should have check my wire strippers.

PeteM
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Re: Leica DM

#7 Post by PeteM » Thu Jul 02, 2020 7:17 am

No problem. Do have a question - though on the head. Are you sure it's a Leica DM IL with the calipers measuring it? See my note above - no idea what size a Leica DM IL is, but could be the one you measured is an older Leitz?

apochronaut
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Re: Leica DM

#8 Post by apochronaut » Thu Jul 02, 2020 12:43 pm

Thankyou for the suggestions. I probably don't want to alter the dovetail socket, since the existing head is good. One of the ideas for the male dovetail will work.
However, the picture of the head you measured microb, doesn't quite fit with what I am looking at. Different part # too.
If it does turn out to be 44.7mm, perhaps it will be a question of material removal. Irregardless, it is close enough that the conversion won't be painfull.

Hobbyst46
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Re: Leica DM

#9 Post by Hobbyst46 » Thu Jul 02, 2020 1:31 pm

As a temporary check, could put a tight-fitting o-ring on the male dovetail. They come in all string sizes. Some are made of strong polymers, though are less elastic than simple rubber so must be within a few millimeters of the final diameter.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

apochronaut
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Re: Leica DM

#10 Post by apochronaut » Thu Jul 02, 2020 1:57 pm

Thanks. I have used those in the past and have dozens of sizes, so a fallback solution. I was planning on using Reichert 24mm f.o.v. eyepieces , so depending on the size of the DM's optical tube, centering could be more or less of an issue. The DM is supposed to be a 20mm f.o.v., so based on that, despite having 30mm eyepieces, the usefull optical surfaces might be smaller than expected.

microb
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Re: Leica DM

#11 Post by microb » Thu Jul 02, 2020 8:33 pm

PeteM wrote:
Thu Jul 02, 2020 7:17 am
No problem. Do have a question - though on the head. Are you sure it's a Leica DM IL with the calipers measuring it? See my note above - no idea what size a Leica DM IL is, but could be the one you measured is an older Leitz?
So here are links to posts about the DM IL that I have. Before the LED model, they had Leitz heads on them. I guess that this was a model done during the company merger?

Here are my posts, and the head matches the ones on e-bay:
viewtopic.php?f=5&t=8297
viewtopic.php?f=14&t=9204
viewtopic.php?f=5&t=9280

Ebay lists randomly chosen as examples:
https://www.ebay.com/itm/Leica-Leitz-DM ... SwxDJcKK1J
https://www.ebay.com/itm/Leica-Leitz-Mi ... Sw44BYUbjG

I bought a trinocular head as well to replace the binocular mine came with. Both dovetails are the same size.

microb
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Re: Leica DM

#12 Post by microb » Thu Jul 02, 2020 8:34 pm

apochronaut wrote:
Thu Jul 02, 2020 12:43 pm
Thankyou for the suggestions. I probably don't want to alter the dovetail socket, since the existing head is good. One of the ideas for the male dovetail will work.
However, the picture of the head you measured microb, doesn't quite fit with what I am looking at. Different part # too.
If it does turn out to be 44.7mm, perhaps it will be a question of material removal. Irregardless, it is close enough that the conversion won't be painfull.
I guess you have one of the newer ones:
https://www.ebay.com/itm/Leica-DMIL-M-I ... 2630595787

Scarodactyl
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Re: Leica DM

#13 Post by Scarodactyl » Thu Jul 02, 2020 9:00 pm

I wonder if something like copper corner trim (like a really light copper angle iron) could be bent into shape to hug the dovetail. Seems like it might hold everything nicely if it worked, though that'd be a bit of a crapshoot.

apochronaut
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Re: Leica DM

#14 Post by apochronaut » Thu Jul 02, 2020 9:41 pm

microb wrote:
Thu Jul 02, 2020 8:34 pm
apochronaut wrote:
Thu Jul 02, 2020 12:43 pm
Thankyou for the suggestions. I probably don't want to alter the dovetail socket, since the existing head is good. One of the ideas for the male dovetail will work.
However, the picture of the head you measured microb, doesn't quite fit with what I am looking at. Different part # too.
If it does turn out to be 44.7mm, perhaps it will be a question of material removal. Irregardless, it is close enough that the conversion won't be painfull.
I guess you have one of the newer ones:
https://www.ebay.com/itm/Leica-DMIL-M-I ... 2630595787
Probably. It is white. Doesn't look like that one, though. It is a trinocular, so the deviating housing is bigger.

apochronaut
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Re: Leica DM

#15 Post by apochronaut » Thu Jul 02, 2020 9:44 pm

Scarodactyl wrote:
Thu Jul 02, 2020 9:00 pm
I wonder if something like copper corner trim (like a really light copper angle iron) could be bent into shape to hug the dovetail. Seems like it might hold everything nicely if it worked, though that'd be a bit of a crapshoot.
I do have some thin copper. That was my earlier idea. Thin copper shimstock or maybe thin aluminum.

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