Cutting Thin Slots

Hi,

I'm really new to this type of thing, I don't even have any of the machines. I make furniture and want to make some of my own hardware. I also make hand saws.

I was wondering what the best machine and setup would be to cut a thin slot, .020", about 1/4" to 3/8" deep, into brass bar, maybe 10"-14" in length.

I was thinking a slot saw blade or a micro drill bit. Would a horizontal mill or vertical mill be better? From what I have gathered it seems like a vertical mill is more versatile. Can anyone recommend a good entry level machine?

Thanks for any advice.

dylan said:

Hi,

I'm really new to this type of thing, I don't even have any of the machines. I make furniture and want to make some of my own hardware. I also make hand saws.

I was wondering what the best machine and setup would be to cut a thin slot, .020", about 1/4" to 3/8" deep, into brass bar, maybe 10"-14" in length.

I was thinking a slot saw blade or a micro drill bit. Would a horizontal mill or vertical mill be better? From what I have gathered it seems like a vertical mill is more versatile. Can anyone recommend a good entry level machine?

Thanks for any advice.

Click to expand...

Cutting a .020" wide slot to the length and depth you want would be murder with an end mill. A slitting saw is what you need. Of coarse, a slitting saw will not give you a nice square end and that is what you need, you may have to finish with an end mill. I have worked in brass with carbide end mills of the size you mentioned and they work well as long as you remember their size. If you push them too hard, either with cutting speed or depth of cut, they will break.

As far as machines go, for a slitting saw a horizontal mill is ideal but you can use a vertical mill with a bit of ingenuity in fixturing. You would need a vertical mill to complete the cuts with an end mill. As far as recommendations for specific machines, there are others on this forum that are better able to advise you on that subject. A lot depends upon your budget. Generally, larger is better as it is more rigid due to its increased mass but people do some very nice work on hobby machines. You can get a better class of machine for the money if you buy used but for someone just getting into it, that may not be the best route as you may end up with inheriting someone else's problems. I have had some good experience with Grizzly machines and Precision Matthews seems to have a strong following on this site.

Good Luck and welcome to the forum!

Bob

I agree with Bob - a slitting saw is what you need. If you are going to bury a blade in that slot then the bottom doesn't have to be square I would think. If your brass stock is going to be round then the problem is going to be holding that long piece solidly while you cut a slot down the center. It can be done but the potential for movement is there. If I was to do this for production I would have a fixture to hold the work piece.

A vertical mill is going to be the most versatile machine for metal working in your shop and I would definitely go with one of these. I'm not even sure if you can buy a new horizontal mill anymore so a used one is probably going to be it, along with its wear and tear problems.

I've done a fair bit of slitting saw work now with my Clausing 8520, which is a hobby sized mill (6" x 24" table). Some of the parts that I have slotted have had fixtures that were more work than the finished part. So yes, slitting and slotting can be done on a vertical mill, but it can be a bit tricky, especially if the slot is cut at an angle or through the end of a round part.

I always thought it would be neat to have a shaper, but I have come to realize that a small horizontal mill will be my next major purchase as it would be a very useful addition to my shop.

As for new horizontal mills, it sticks in my mind that Grizzly offers a couple of combo mills that are both horizontal and vertical. One machine is full sized and the other is a small one.

Thanks for the replies and advice.

I think Mikey is right, and I can do without the end mill for now, because I don't think the condition of the bottom of the slot will matter all that much for what I am trying to accomplish.

I think I will look into a vertical mill and spend some time designing a mixture to hold the brass in place because keeping the slot as straight as possible is essential.

This may be a stupid question, but when a milling machine lists a bed size, is that entire size usable? If the table is 6" x 24" will the milling head be able to access every square inch?

Dylan

dylan said:

This may be a stupid question, but when a milling machine lists a bed size, is that entire size usable? If the table is 6" x 24" will the milling head be able to access every square inch?

Dylan

Click to expand...

No, the whole bed is not usable in that the spindle cannot access all of the bed. Look for a spec on x, y, and z travel to get your work space.

And not a stupid question.

Bob

Ah, Thanks Bob, I thought it would be similar to the bed size/between centers distinction.

And with that, everything just became a lot smaller and much more expensive.

dylan said:

And with that, everything just became a lot smaller and much more expensive.

Click to expand...

You can slide your fixture to enable you to slot a long workpiece as long as you have means to accurately locate the fixture in the X-axis. This isn't difficult as there are T-slots to fix locating blocks or whatever you plan to use. Then you can slide the fixture along and re-clamp it. Not a big deal.

It is wise to buy the biggest mill you can afford. Look around, ask here before you jump and you'll be fine.

dylan said:

Ah, Thanks Bob, I thought it would be similar to the bed size/between centers distinction.

And with that, everything just became a lot smaller and much more expensive.

Click to expand...

With milling machines I think you loose about 6" on each end. That includes room to access the Tee slots and the end caps/plates underneath that holds the lead screw.

If I had the chance and money I'd look into the combo type mill, there are several makers who do make them , some used on eBay too in the last week or two I saw a jet I think that was under $2,000 in the combo set up , but even some of the small horizontal mills will do the job you want and some of those are under $1,000 , in fact I saw anice one for $299. In Pennsylvania may have been on Craigslist tho. Wish I had good legs I'd have been buying that one , but when your stuck in a wheelchair it dont happen. All my so called friends over the years don't even stop or call. Keep looking youll find what you need don't just buy what others have lots of good mills out there.