PDA

View Full Version : Step clamp design - Hold down thin or irregular shaped objects while milling!



Lee Roberts
14-04-2012, 07:06 PM
Just been reading a thread about clamping and a design someone is working on, in view of that thread i thought i would post this for other people who may like to "have ago" at making their own.

This design is Project 2 from Roy over at www.diycnc.co.uk (http://www.diycnc.co.uk)

5781


It is not always convenient to uses a vice to hold an object or piece of material when milling. It is often better to use clamps and spacers to hold down the item. These small step clamps give you 2 mm steps from 4 to 24 mm and can be used with a separate bar or on their own via the bolt slot. I have used 25mm square aluminium bar which is a common stock size. The cutter used is a 5 mm slot drill as it entails a lot of pocketing operations.

Note: The Code has only been tested on my own converted milling machine using Mach 3 software. You may need to edit the code to suit the feed speeds and parameters of your own machine. The start reference point is the top left hand corner and a tool clearance of 2.5 mm. The G-Code consists of plunge rough routing and horizontal finishing routines.

Below are the files to go with this project.

Web Goblin
14-04-2012, 10:00 PM
Lee,
I have been looking at this type of clamp as well. We have a set at work for our Bridgeport. The only problem I have seen is that the steps on our set are slightly angled in towards the body of the part. I presume this is to stop it from sliding apart when used with a bar. I was thinking about having a go at milling one with a section of bar clamped to the table at a slight angle.

Ian

Jonathan
14-04-2012, 11:23 PM
Is it really worth it? A set of clamps intended for the milling machine isn't too expensive and gives you all sorts of options, although sod's law does still apply.

With the clamp pictured I'd be worried that the distance between the end nearest the work and the higher surfaces will be too great and could get in the way?

Lee Roberts
15-04-2012, 02:13 AM
Is it really worth it? A set of clamps intended for the milling machine isn't too expensive and gives you all sorts of options, although sod's law does still apply.

With the clamp pictured I'd be worried that the distance between the end nearest the work and the higher surfaces will be too great and could get in the way?

Well i guess they could be a good buy i've just been looking at a kit for 38.95 on ebay (http://www.ebay.co.uk/itm/52-pc-CLAMPING-KIT-MILLING-MACHINE-METRIC-M12-STUD-/330666875329?pt=UK_BOI_Metalworking_Milling_Weldin g_Metalworking_Supplies_ET&hash=item4cfd4819c1#ht_2258wt_829&clk_rvr_id=332457138086&afsrc=1) that seems reasonable and would cover allot of jobs/use's.

I think* Roy's intention:


You may need to edit the code to suit the feed speeds and parameters of your own machine.

Was to just give you a project you could have ago at with your own machine and then would expect you to find your own feet. A kit like that is also heat treated steel so should last better in the work shop vs soft ali, so that is also something to consider.

What clamps do you make use of the most Jonathan ?

.Me

Jonathan
15-04-2012, 12:50 PM
What clamps do you make use of the most Jonathan ?

On the milling machine I use the ones you linked to. On the router I'm still using an MDF bed so I just use wood screws for everything directly into the bed. Got some large M6 washers (about 25mm external diameter) I sometimes use with blocks to support the other 'side'xof the washer. I keep all the little offcuts of aluminium to use as spacers for supporting screws when clamping.

Web Goblin
15-04-2012, 01:36 PM
Yes I can buy then but wanted to have a go at making some. There is also this set http://www.arceurotrade.co.uk/Catalogue/Workholding/Clamping-Sets available. Might be better for the smaller milling machines using 6mm bolts.

Ian