Help! cutting dovetail for slide racker - 360 X 60 or what?! -

[BeerBaron]

Hi Guys,

Need some help. Want to cut my old SV for a racker. It's already enough of a challenge as the rear is flat topped and there is not much meat between the breach face and where the flat topping starts.

Ordinarily that would still be fine but this is an IBF slide so part of that meat in there is the IBF and IBF screw... d'oh...

On the plus side is the flat top is not as deep as some and I may in fact still have enough meat to cut the dovetail in the flat top.

Anyway I digress.

The real issue is this:

I purchased a brazos zigracker to use for this gun. this one: http://www.1911store.com/slide-racker-bcg-zigracker-1.aspx

Now as best I knew it uses a 'normal' GI/bomar type dovetail (360 X 60) but stop short of cutting right through the slide.

So I ordered up my expensive cutter from brownells and it's on the way. So last night I thought I'll pull out ye olde instructions and have a gander...

well strike me lucky. the instructions call for a 375 X 60 (aka 3/8 X 60) dovetail cutter.!?! WTH?

I was a bit surprised so I pulled out the racker itself. At it's widest point it measures about .355... ok. For comparison I whipped out another racker I have lying around (shooters connection/EGW sidewinder XL which I KNOW is for a 360X60 dovetail) and it measures the same (it has been slightly filed to fit a tight dovetail on a tanfoglio).

So the questions are these:

Has anyone here fitted a brazos zigracker and can share their experience? What cutter did you use etc?

If I do need to cut a 375 X 60 dovetail my feeling is I could do one pass with the 360, then move 0.015 over and do another pass thus giving me my 0.375 cut. Is that idea sound?

Given the brazos seems to be the same size as my sidewinder does it seem more likely that it needs the GI/bomar 360X60 dovetail and that the instructions are wrong (perhaps out of date?).

Any other tips on dealing with a slide that only has small real estate behind the breach would be great.

Finally, I obviously don't want to cut anywhere near the IBF screw, but what about if part of the dovetail is in the back of the IBF itself? I can't see that being a problem?

Thanks guys. This one has got me knackered!

for reference this is what the IBF looks like: you can see it goes a little way into the slide.

Edited May 20, 2016 by BeerBaron

[MrPostman]

I did this one 2 weeks ago and I had to buy the .375 x 60 dovetail cutter. I have a .359 x 60 but i was afraid that the rounded portion at the end of the racker wouldn't look clean if I used the .359 and moved it over .015. The instructions tell you what and where to do the cuts with a shelf cut on the rear, like on a STI Grandmaster of Steel master but you may have a problem with the IBF.

Sent from my SAMSUNG-SM-G935A using Tapatalk

Edited May 21, 2016 by MrPostman

[BrianATL]

It will work fine the way you are describing you can just mover over and nibble away til you get a snug fit.

[BeerBaron]

Thanks for the tips guys. Awesome pic mr postman. That's about the same amount of space I have to work with. Really helpful.

I didn't buy the exact part number 375x60 cutter they reccomend in the instructions (it was $145 at msc) but I did buy a cheap 375x60 off ebay ($20). I hope it works I only need to cut one dovetail!

I still can't understand how a dovetail made with the 375 cutter will fit my racker that measures about 352 across the base.

Can you do me a favour and measure the base width on your racker mr postman? It would help me rest easy if I know yours is around 350 or so and that the 375 cutter was correct.

I'm worried they have the wider 375 type rackers and others to fit a gi/bomar dovetail and I got the wrong instructions.

[BeerBaron]

What's got me confused is I have an EGW racker here which I know is to fit a 360x60 dovetail (which you cut with the 359x60 cutter). It measures the same width as my brazos zig racker (in fact the egw is a tiny bit wider which makes sense as it's the gunsmith fit version which comes slightly oversize).

I just can't see how 2 rackers the same size coupd fit different dovetails!

[MrPostman]

This is actually one I did for a customer and if I remember correctly it was .353" wide at the base. The cutter I bought was a HSS one from Pacific tool and gauge and it was $23 plus shipping. Generally I prefer to use carbide but this one cut the slide no problem.

In my experience when cutting slides for rackers that the stated measurement is .360x60 I usually have to make a few more passes to get the racker to fit (like another .006 to .015) when using my .359x60 cutter. The reason for this is that the bottom of the racker is beveled slightly at the bottom instead of edged, so the measurement you are getting from the bottom is really the width of the racker .010"- .020" above the bottom.

So that is the reason they suggest the .375x60, so you only have to make one pass to make it fit and therefore a cleaner looking installation, especially at the end where it is rounded.

FYI it fit perfectly using the .375 and the 1/8 rounded endmill for the detents so the balls have a place to lock into. The instructions do suggest a .003" cut on either side of the dovetail cut with a 3/16 end mill so it fits correctly at the top of the racker.

So to sum up the .375x60 is the correct cutter

[BeerBaron]

Thanks mr postman.

That makes sense. It puts my mind at ease. It had me scratching my noodle a bit!

Nice job on the install. I'm sure it was a happy customer.

[MrPostman]

You're welcome! Thanks! Yep he was thrilled lol.

Edited May 21, 2016 by MrPostman

[Brazos Custom]

You will need the 0.375 x 60 degree cutter to do it right. Smaller dovetails often don't cut the entire 0.187 depth needed and if you use a smaller dovetail you will end up with a flat across the cut instead of a radius. Dovetails are properly measured theoretical point to theoretical point. You have to use a set of pins and calculate the measurement to do it properly. Once you chamfer the edges and don't have a point and the measurement will be smaller.The edges are rounded to help with fitting and to knock any burrs off. The instructions are current, very detailed, and if followed to the letter will result in a very nice, clean installation. Carbide cutters are expensive but do a much better job.

[MrPostman]

You will need the 0.375 x 60 degree cutter to do it right. Smaller dovetails often don't cut the entire 0.187 depth needed and if you use a smaller dovetail you will end up with a flat across the cut instead of a radius. Dovetails are properly measured theoretical point to theoretical point. You have to use a set of pins and calculate the measurement to do it properly. Once you chamfer the edges and don't have a point and the measurement will be smaller.The edges are rounded to help with fitting and to knock any burrs off. The instructions are current, very detailed, and if followed to the letter will result in a very nice, clean installation. Carbide cutters are expensive but do a much better job.

Great too see the man himself posting on this. I completely agree about the carbide preference, I have just had good results with Pacific Tool and Carbide HSS tools so I figured it would do a good cut and it did

FYI the instructions are excellent!

Edited May 22, 2016 by MrPostman

[BeerBaron]

You will need the 0.375 x 60 degree cutter to do it right. Smaller dovetails often don't cut the entire 0.187 depth needed and if you use a smaller dovetail you will end up with a flat across the cut instead of a radius. Dovetails are properly measured theoretical point to theoretical point. You have to use a set of pins and calculate the measurement to do it properly. Once you chamfer the edges and don't have a point and the measurement will be smaller.The edges are rounded to help with fitting and to knock any burrs off. The instructions are current, very detailed, and if followed to the letter will result in a very nice, clean installation. Carbide cutters are expensive but do a much better job.

Thanks for posting.

Firstly I'd like to say the racker is a lovely piece of work and worth every bit of the $75 (for the x long one).

I did cheap out on the 375 cutter as I'd already blown $65 on the Brownells 359 cutter! D'oh!

I do agree the instructions are very easy to follow, very precise and simple enough that even a moron like me can follow them!

I hope I caused no offense. I respect the work you do at brazos highly and I'll say in the often secretive world of gunsmiths you are very free with sharing knowledge on topics like mag tuning, extractor tuning etc which I greatly appreciate.

Now I just wait for my el-cheapo cutter to arrive and I can fit this thing.

Thanks for taking the time to enlighten my ignorance. It's much appreciated.

[BeerBaron]

For anyone still interested my order from Brownells arrived including my (now somewhat useless) 359x60 cutter. I'm just now waiting on the 375 ebay one and I'll give this a go.

The Brownells cutter just has 4 flutes/cutters on it. I'm not sure why but being such a small thing I kind of expected 5 or 6.

I just put a new uncut 17lb hammer spring in my sv (it seemed to have a 17 or maybe 15 that had quite a few coils cut). With the new hammer spring it's much harder to rack from an empty chamber start so now I'm really keen to get a racker on it!

[BeerBaron]

I thought I'd update since I got such great help. I did cheap out and use the 360 brownells cutter. it did work just fine, but as Bob advised we did have to widen the slot a little. The smith that helped me with this did a great job. between the two of us we nutted out a way to fit it that is still pretty neat.

we didn't have enough room behind the interchangeable breach face to cut the dovetail without also cutting into the breach. I was ok with that but he talked me out of it. We also didn't have enough room on the flat top to cut a full depth dovetail for this racker (it's on the taller end of the scale racker wise).

In the end we compromised and cut right at where the rear swoop cut is. so the front of the racker is below that surface while the rear protrudes just a tiny bit above. We then cut of the corner at 45 and it looks pretty neat.

I'll put up a few pics if anyone's interested. The racker is certainly a quality piece. Can't wait for a table start now!!!

[MrPostman]

That's great! Glad you got it installed, I personally would like to see some pics

[Dr Mitch]

Pics!!!

[BeerBaron]

no worries. pics it is.

The gun is still a bit of a project. the refresh plans are:

new cheely setback 90 mount with cmore slide ride (have the mount with custom hole pattern - thanks to Matt Cheely).

the new super large racker (now done, and with thanks to Brazos for the great product and instructions)

need to replace some small bits (grip screws are nicely seized up and the heads a bit hammered for starters, some scope mount screws were knackered too)

Took apart the barrel and comp which is an interesting sleeved barrel (sleeve is full length to just before the forward most locking lug and basically no taper so slide is clearanced inside, I should weigh the slide, I'd guess it's light)

new magwell (dawson ICE in red - just waiting for them to come back into stock at SSI)

swapping in a red enos bottom curve trigger insert (got that)

Phoenix Trinity shielded ambis

I will also consider cutting back the dust cover if I don't like the balance. interestingly without a scope the balance point on my finger is behind the trigger guard. actually it balances on my finger nicely just in front of the trigger shoe which is slightly to the rear of the mid point so if anything it's still rear heavy even without a mag in it (heavy magwell helps no doubt).

The new scope setup is well set back so balance shouldn't change too much. Light slide and titanium comp help I'm sure.

Anyway some pics of she is now half way to being re-furbed. sans scope for now, but with racker.

The cut:

Thanks again for the help and advice. As I said I did end up using the 360 cutter I had and we did have to make a few extra passes on each side to widen the dovetail but any non radiused part at the end of the cut is not noticeable thankfully. Certainly the 375 cutter is the correct size to use! The fit is very tight but still easy to get in and out by hand no problem.

[BoyGlock]

Can it be positioned a bit to the rear so it clears the slanting surface? I have similar scallop in my slide and planning to copy yours if you dont mind

[BeerBaron]

the problem with going any further rear is not enough meat before you hit firing pin tunnel. as it is I left only about 0.8mm of thickness above the firing pin channel.

now personally I was brave enough to cut into it but the last thing you want is to create unreliability but getting the spring to catch on the hole etc.

Normally you'd put it completely into the uncut part behind the breach but my problem was it's an SVI so it has a removeable breach face which goes back a ways from the actual breach face. in a non SVI slide it's not an issue.

what I did was compromise. We had a spare SVI breach face on the bench and measured it up to determine how far back we needed to go to clear it. then we measured to figure how deep we could go on the flat topped part. So at the rear I have just under 1mm of the racker above the flat top of the slide. at the front of the racker it's about 2mm below the surface of the bit behind the breach. to make that work we had to make a small pass straight across to create some clearance for the shank of the dovetail cutter. that is why there's a 45 degree cut to neaten that part up.

In the end it looks pretty neat and I'm super happy with the position. with a normal scope mount it fits no problem and even with a heavily setback mount like a cheely setback 90 mount it still clears the cmore and mount just fine.

If you have an issue like I did with no enough room behind the breach and not enough meat in the rear flat top this compromise works really well.

The other option is use a racker that is not as 'tall' in the dovetail. the brazos is quite tall as it contains the springs and balls. something like a cheely racker has a dovetail about half as tall so you could probably cut that into the flat topped section no problem. from memory the brazos was 4.8mm high and the cheely about 3mm. then you either have to fit a set screw or put a ball and spring in the slide. that should be fine you just put it on the left side so it's not going into the extractor tunnel or firing pin tunnel. you could probably just use a single ball (which should hold fine).

This one uses two balls and has them in the racker which in some ways simplifies things.

usually this is straight forward. it's just guns like mine that had the slide cut without consideration of a racker...

[BoyGlock]

Thank you. Thats very helpful of you. Checked my slide and it seems it doesnt have much thickness to accomodate the brazos. The slide cut is a bit deeper than yours. My goal was to make this gun's racker consistent with my other guns so I dont consider other options except the brazos.

[jmorris]

I have not needed to cut dovetails for sights much and every time I do, I don't feel like waiting a week.

So I have a few triangle files that I have ground "the bottom" smooth and to the proper angle for the sight I was fitting. Mill the slot then the "safe" side is the bottom and won't cut any deeper as you create the dovetail on either side.

Your done with the project before you could have looked up and ordered the dovetail cutter but of course that is for a dovetail that passes completely through.

Edited August 5, 2016 by jmorris

[MrPostman]

Looks good BeerBaron!

[Paul-the new guy]

I have what I assume is the correct cutter, The gunsmith that installed mine made me buy it... If anyone needs it I will let it go cheap.

Edited August 5, 2016 by Paul-the new guy

[MrPostman]

I have what I assume is the correct cutter, The gunsmith that installed mine made me buy it... If anyone needs it I will let it go cheap.

Made you buy it? I bought one to do the one I did for a friend but I sure as hell didn't charge him for a tool I most likely will use again.

[BeerBaron]

Thank you. Thats very helpful of you. Checked my slide and it seems it doesnt have much thickness to accomodate the brazos. The slide cut is a bit deeper than yours. My goal was to make this gun's racker consistent with my other guns so I dont consider other options except the brazos.

Yeah I should have mentioned the rear swoop/flat top area on mine is fairly conservative. It's not as low as most are cut these days. But I did have nothing to work with behind the breach. In the end I'm happy with the compromise we made. It's not as pretty as it being 100% flush but it's functional and still looks neat enough.

[BeerBaron]

Thank you. Thats very helpful of you. Checked my slide and it seems it doesnt have much thickness to accomodate the brazos. The slide cut is a bit deeper than yours. My goal was to make this gun's racker consistent with my other guns so I dont consider other options except the brazos.

You do have the option to not cut to full depth. I'd suggest measure the depth from the flat area to top of firing pin tunnel. From memory the brazos racker wants the dovetail cut 0.188 deep (4.8mm). You could shorten that depth down to 0.150 (3.8mm) without any issue except cosmetics. And it won't look horrible.

Even 0.140 would likely be totally fine (3.5mm).

My pure guess is that you want at least 0.118 (3mm) depth in the dovetail cut for this racker to ensure nothing nasty happens.

Much smaller than that is starting to press your luck. Again these are purely my guesses. I have a racker in my tanfoglio gold team and off the top of my head that cut (also .360 x 60) is only 0.118 deep. It holds fine and that racker is alluminium not steel like the brazos.

I agree it's worth keeping your guns setup the same.